title:
Search for Higgs Bosons and New Particles Decaying into Two Photons at
  sqrt(s) = 183 GeV

abstract:
  A search for the resonant production of high mass photon pairs associated
with a leptonic or hadronic system has been performed using a data sample of
57.7 pb-1 collected at an average center-of-mass energy of 182.6 GeV with the
OPAL detector at LEP. No evidence for contributions from non-Standard Model
physics processes was observed. The observed candidates are used to place
limits on BR (H to gamma gamma) assuming a Standard Model production rate for
Higgs boson masses up to 92 GeV, and on the production cross section for a
scalar resonance decaying into di-photons up to a mass of 170 GeV. Upper limits
on the product of cross section and branching ratios, sigma(e+e- to XY) * BR(X
to gamma gamma) * BR(Y to f fbar) as low as 70fb are obtained over the M(X)
range 10 - 170 GeV for the case where 10 < M(Y) < 160 GeV and M(X)+M(Y) > 90
GeV, independent of the nature of Y provided it decays to a fermion pair and
has negligible width. Higgs scalars which couple only to gauge bosons at
Standard Model strength are ruled out up to a mass of 90.0 GeV at the 95%
confidence level. Limits are also placed on non-minimal Higgs sectors having
triplet representations.


title: A measurement of $alpha_s(Q^2)$ from the Gross-Llewellyn Smith Sum Rule

abstract:
  We extract a set of values for the Gross-Llewellyn Smith sum rule at
different values of 4-momentum transfer squared ($Q^{2}$), by combining revised
CCFR neutrino data with data from other neutrino deep-inelastic scattering
experiments for $1 < Q^2 < 15 GeV^2/c^2$. A comparison with the order
$\alpha^{3}_{s}$ theoretical predictions yields a determination of $\alpha_{s}$
at the scale of the Z-boson mass of $0.114 \pm^{.009}_{.012}$. This measurement
provides a new and useful test of perturbative QCD at low $Q^2$, because of the
low uncertainties in the higher order calculations.


title: Measurement of the Michel Parameters in Leptonic Tau Decays

abstract:
  The Michel parameters of the leptonic tau decays are measured using the OPAL
detector at LEP. The Michel parameters are extracted from the energy spectra of
the charged decay leptons and from their energy-energy correlations. A new
method involving a global likelihood fit of Monte Carlo generated events with
complete detector simulation and background treatment has been applied to the
data recorded at center-of-mass energies close to sqrt(s) = M(Z) corresponding
to an integrated luminosity of 155 pb-1 during the years 1990 to 1995. If e-mu
universality is assumed and inferring the tau polarization from neutral current
data, the measured Michel parameters are extracted. Limits on non-standard
coupling constants and on the masses of new gauge bosons are obtained. The
results are in agreement with the V-A prediction of the Standard Model.


title:
Heavy quark mass effects and improved tests of the flavour independence
  of strong interactions

abstract:
  A review is given of latest results on tests of the flavour independence of
strong interactions. Heavy quark mass effects are evident in the data and are
now taken into account at next-to-leading order in QCD perturbation theory. The
strong-coupling ratios alpha_s^b/alpha_s^uds and alpha_s^c/alpha_s^uds are
found to be consistent with unity. Determinations of the b-quark mass m_b(M_Z)
are discussed.


title:
Light-Front Analysis of pi^{-} Mesons Produced in Mg - Mg Collisions at
  4.3 a Gev/c

abstract:
  Light-front analysis of pi^{-} mesons in Mg-Mg collisions is carried out. The
phase space of secondary pions is naturally divided into two parts in one of
which the thermal equilibration assumption seems to be in a good agreement with
data. Corresponding temperatures are extracted and compared to the results of
other experiments. The experimental results have been compared with the
predictions of the Quark Gluon String Model (QGSM) and satisfactory agreement
between the experimental data and the model has been found.


title:
Measurement of the Strong Coupling Constant and the Vector and
  Axial-Vector Spectral Functions in Hadronic Tau Decays

abstract:
  The spectral functions of the vector current and the axial-vector current
have been measured in hadronic tau decays using the OPAL detector at LEP.
Within the framework of the Operator Product Expansion a simultaneous
determination of the strong coupling constant alpha_s, the non-perturbative
operators of dimension 6 and 8 and of the gluon condensate has been performed.
Different perturbative descriptions have been compared to the data. The Contour
Improved Fixed Order Perturbation Theory gives alpha_s(mtau**2) = 0.348 +-
0.009 +- 0.019 at the tau-mass scale and alpha_s(mz**2) = 0.1219 +- 0.0010 +-
0.0017 at the Z-mass scale. The values obtained for alpha_s(mz**2) using Fixed
Order Perturbation Theory or Renormalon Chain Resummation are 2.3% and 4.1%
smaller, respectively. The running of the strong coupling between s_0 ~1.3
GeV**2 and s_0 = mtau**2 has been tested from direct fits to the integrated
differential hadronic decay rate R_tau. A test of the saturation of QCD sum
rules at the tau-mass scale has been performed.


title: Exclusive Electroproduction of $\rho^0$ and $J/\psi$ Mesons at HERA

abstract:
  Exclusive production of $\rho^0$ and $J/\psi$ mesons in e^+ p collisions has
been studied with the ZEUS detector in the kinematic range $0.25 < Q^2 < 50
GeV^2, 20 < W < 167 GeV$ for the $\rho^0$ data and $2 < Q^2 < 40 GeV^2, 50 < W
< 150 GeV$ for the $J/\psi$ data. Cross sections for exclusive $\rho^0$ and
$J/\psi$ production have been measured as a function of $Q^2, W$ and $t$. The
spin-density matrix elements $r^{04}_{00}, r^1_{1-1}$ and $Re r^{5}_{10}$ have
been determined for exclusive $\rho^0$ production as well as $r^{04}_{00}$ and
$r^{04}_{1-1}$ for exclusive $J/\psi$ production.
  The results are discussed in the context of theoretical models invoking soft
and hard phenomena.


title: W Boson Physics at the Fermilab Tevatron Collider

abstract:
  This talk at the XVIII International Conference on Physics in Collision,
Frascati, Italy, June 17-19, 1998, presents CDF and D0 results on W and Z Boson
Production Cross Sections, the W Boson Width, Rare W Boson Decays, Trilinear
Gauge Boson Couplings, and the W Boson Mass.


title: Highlights and Open Questions from ZEUS

abstract:
  The latest results from the ZEUS experiment, as presented at the DIS98
workshop, are reviewed. A brief introduction to the status of the experiment is
given. The review focuses on three areas: multi-scale problems in QCD including
results on jets, charm, the dynamics of $F_2$ at low $Q^2$, forward jets and
fragmentation functions; diffractive structure including results on $\Upsilon$
production, inclusive diffraction in DIS, event shapes and leading baryon
production; and, the measurement and interpretation of the high-$Q^2$ neutral
and charged current cross-sections.


title:
Tests of the Standard Model and Constraints on New Physics from
  Measurements of Fermion-pair Production at 183 GeV at LEP

abstract:
  Cross-sections for hadronic, b-bbar and lepton pair final states in e+e-
collisions at sqrt(s) = 183 GeV, measured with the OPAL detector at LEP, are
presented and compared with the predictions of the Standard Model.
Forward-backward asymmetries for the leptonic final states have also been
measured. Cross-sections and asymmetries are also presented for data recorded
in 1997 at sqrt(s) = 130 and 136 GeV. The results are used to measure the
energy dependence of the electromagnetic coupling constant alpha_em, and to
place limits on new physics as described by four-fermion contact interactions
or by the exchange of a new heavy particle such as a leptoquark, or of a squark
or sneutrino in supersymmetric theories with R-parity violation.


title: Electroproduction of the Delta Resonance at High Momentum Transfer

abstract:
  We studied the electroproduction of the Delta(1232) resonance via the
reaction p(e,e'p)\pi0 at four-momentum transfers Qsq = 2.8 and 4.0 GeV^2. This
is the highest Qsq for which exclusive resonance electroproduction has ever
been observed. Decay angular distributions for Delta to p-pi0$ were measured
over a wide range of barycentric energies covering the resonance. The
$N-\Delta$ transition form factor G*_M and ratios of resonant multipoles
E{1+}/M{1+} and S{1+}/M{1+} were extracted from the decay angular
distributions. These ratios remain small, indicating that perturbative QCD is
not applicable for this reaction at these momentum transfers.


title: Production of Chi_c2 Mesons in Photon-Photon Collisions at LEP

abstract:
  We present an observation at LEP of the production of chi_c2 mesons in the
collisions of two quasi-real photons using the OPAL detector. The chi_c2 mesons
are reconstructed in the decay channel Chi_c2 to J/psi gamma to l+l- gamma
(with l= e,mu) using all data taken at e+e- centre-of-mass energies of 91 and
183 GeV, corresponding to integrated luminosities of 167 and 55 pb-1
respectively. The two-photon width of the Chi_2 is determined to be 1.76 +-
0.47 +- 0.37 +- 0.15 keV where the first error is statistical, the second is
systematic and the third comes from branching ratio uncertainties.


title:
Search for Scalar Top and Scalar Bottom Quarks at sqrt(s) = 183 GeV at
  LEP

abstract:
  Searches for a scalar top quark and a scalar bottom quark have been performed
using a total data sample of 56.8 pb-1 at a centre-of-mass energy of 183 GeV
collected with the OPAL detector at LEP. No candidate events were observed.
Combining this result with those obtained at lower centre-of-mass energies, the
95% C.L. lower limit on the scalar top quark mass is 85.0 GeV if the mixing
angle between the supersymmetric partners of the left- and right-handed states
of the top quark is zero. The lower limit is 81.3 GeV, even if the scalar top
quark decouples from the Z boson. These limits were obtained assuming that the
scalar top quark decays into a charm quark and the lightest neutralino, and
that the mass difference between the scalar top quark and the lightest
neutralino is larger than 10 GeV. Assuming a relatively light scalar neutrino,
The complementary decay mode of the scalar top quark in which it decays into a
bottom quark, a charged lepton and a scalar neutrino was also studied. From a
similar analysis, a mass limit on the light scalar bottom quark was set at 82.7
GeV for a mass difference between the scalar bottom quark and the lightest
neutralino larger than 7 GeV, and at 84.0 GeV for the mass difference larger 10
GeV and the lightest neutralino heavier than 30 GeV. These limits were obtained
assuming that the scalar bottom quark decays into a bottom quark and the
lightest neutralino, and that a mixing angle between the supersymmetric
partners of the left- and right-handed states of the bottom quark is zero.


title:
Di-Jet Production in Photon-Photon Collisions at e+e- center-of-mass
  energies = 161 and 172 GeV

abstract:
  Di-jet production is studied in collisions of quasi-real photons radiated by
the LEP beams at e+e- centre-of-mass energies 161 and 172 GeV. The jets are
reconstructed using a cone jet finding algorithm. The angular distributions of
direct and double-resolved processes are measured and compared to the
predictions of leading order and next-to-leading order perturbative QCD. The
jet energy profiles are also studied. The inclusive two-jet cross-section is
measured as a function of transverse energy and rapidity and compared to
next-to-leading order perturbative QCD calculations. The inclusive two-jet
cross-section as a function of rapidity is compared to the prediction of the
leading order Monte Carlo generators PYTHIA and PHOJET. The Monte Carlo
predictions are calculated with different parametrisations of the parton
distributions of the photon. The influence of the `underlying event' has been
studied to reduce the model dependence of the predicted jet cross-sections from
the Monte Carlo generators.


title: Measurements of R=sigma_L/sigma_T for 0.03<x<0.1 and Fit to World Data

abstract:
  Measurements were made at SLAC of the cross section for scattering 29 GeV
electrons from carbon at a laboratory angle of 4.5 degrees, corresponding to
0.03<x<0.1 and 1.3<Q^2<2.7 GeV^2. Values of R=sigma_L/sigma_T were extracted in
this kinematic range by comparing these data to cross sections measured at a
higher beam energy by the NMC collaboration. The results are in reasonable
agreement with pQCD calculations and with extrapolations of the R1990
parameterization of previous data. A new fit is made including these data and
other recent results.


title: Measurement of the Top Quark Mass in the Dilepton Channel

abstract:
  We report a measurement of the top quark mass using six candidate events for
the process pbarp->ttbar->l^+ nu l^- nubar b bbar + X, observed in the D0
experiment at the Fermilab ppbar collider. Using maximum likelihood fits to the
dynamics of the decays, we measure a mass for the top quark of m(top) = 168.4
+- 12.3 (stat) +- 3.6 (syst) GeV/c^2. We combine this result with our previous
measurement in the ttbar->l+jets channel to obtain m(top) = 172.1 +- 7.1
GeV/c^2 as the best value of the mass of the top quark measured by D0.


title:
First Measurement of Z/gamma* Production in Compton Scattering of
  Quasi-real Photons

abstract:
  We report the first observation of Z/gamma* production in Compton scattering
of quasi-real photons. This is a subprocess of the reaction e+e- to
e+e-Z/gamma*, where one of the final state electrons is undetected.
Approximately 55 pb-1 of data collected in the year 1997 at an e+e-
centre-of-mass energy of 183 GeV with the OPAL detector at LEP have been
analysed. The Z/gamma* from Compton scattering has been detected in the
hadronic decay channel. Within well defined kinematic bounds, we measure the
product of cross-section and Z/gamma* branching ratio to hadrons to be
(0.9+-0.3+-0.1) pb for events with a hadronic mass larger than 60 GeV,
dominated by (e)eZ production. In the hadronic mass region between 5 GeV and 60
GeV, dominated by (e)egamma* production, this product is found to be
(4.1+-1.6+-0.6) pb. Our results agree with the predictions of two Monte Carlo
event generators, grc4f and PYTHIA.


title:
A Study of Parton Fragmentation in Hadronic Z0 Decays Using
  Lambda-Lambdabar Correlations

abstract:
  The correlated production of Lambda and Lambdabar baryons has been studied
using 4.3 million multihadronic Zo decays recorded with the OPAL detector at
LEP. Di-lambda pairs were investigated in the full data sample and for the
first time also in 2-jet and 3-jet events selected with the k_t algorithm. The
distributions of rapidity differences from correlated Lambda-Lambdabar pairs
exhibit short-range, local correlations and prove to be a sensitive tool to
test models, particularly for 2-jet events. The JETSET model describes the data
best but some extra parameter tuning is needed to improve agreement with the
experimental results in the rates and the rapidity spectra simultaneously. The
recently developed modification of JETSET, the MOdified Popcorn Scenarium
(MOPS), and also HERWIG do not give satisfactory results. This study of
di-lambda production in 2- and 3-jet events supports the short-range
compensation of quantum numbers.


title:
Tests of the JETSET Bose-Einstein correlation model in the e+e-
  annihilation process

abstract:
  Studies of implementation of the simulation of the Bose-Einstein correlation
effects in the JETSET particle generator are performed. Analysis of dependance
of the one-dimensional correlation function parameters on the presumed boson
source size reveals appearance of the effective new length scale, which limits
applicability of the simple momentum-shifting mechanism, employed by JETSET to
simulate the Bose-Einstein correlation. Two- and three-dimensional correlation
functions are analysed as well and compared to the DELPHI data.


title: Future Solar Neutrino Projects

abstract:
  A review is presented of several projects under development which aim to be
"third generation" solar neutrino detectors.


title:
Measurement of the Top Quark Pair Production Cross Section in pbar-p
  Collisions Using Multijet Final States

abstract:
  We have studied tbar-t production using multijet final states in pbar-p
collisions at a center-of-mass energy of 1.8 TeV, with an integrated luminosity
of 110.3 pb(-1). Each of the top quarks with these final states decays
exclusively to a bottom quark and a W boson, with the W bosons decaying into
quark-antiquark pairs. The analysis has been optimized using neural networks to
achieve the smallest expected fractional uncertainty on the tbar-t production
cross section, and yields a cross section of 7.1 +/- 2.8(stat.) +/- 1.5(syst.)
pb, assuming a top quark mass of 172.1 GeV/c^(2). Combining this result with
previous D0 measurements, where one or both of the W bosons decay leptonically,
gives a tbar t production cross section of 5.9 +/- 1.2(stat) +/- 1.1(syst) pb.


title:
Measurement of the Longitudinal Cross-Section using the Direction of the
  Thrust Axis in Hadronic Events at LEP

abstract:
  In the process e+e- to hadrons, one of the effects of gluon emission is to
modify the 1+cos(theta)**2 form of the angular distribution of the thrust axis,
an effect which may be quantified by the longitudinal cross-section. Using the
OPAL detector at LEP, we have determined the longitudinal to total
cross-section ratio to be 0.0127+-0.0016+-0.0013 at the parton level, in good
agreement with the expectation of QCD computed to Order(alpha_s**2)
Comparisions at the hadron level with Monte Carlo models are presented. The
dependence of the longitudinal cross-section on the value of thrust has also
been studied, and provides a new test of QCD.


title:
Search for Acoplanar Lepton Pair Events in e+e- Collisions at sqrt{s} =
  161, 172 and 183 GeV

abstract:
  A selection of di-lepton events with significant missing transverse momentum
has been performed using a total data sample of 77.0 pb-1 at e+e-
centre-of-mass energies of 161 GeV, 172 GeV and 183 GeV. The observed numbers
of events: four at 161 GeV, nine at 172 GeV, and 78 at 183 GeV, are consistent
with the numbers expected from Standard Model processes, which arise
predominantly from W+W- production with each W decaying leptonically. This
topology is an experimental signature also for the pair production of new
particles that decay to a charged lepton accompanied by one or more invisible
particles. Further event selection criteria are described that optimise the
sensitivity to particular new physics channels. No evidence for new phenomena
is apparent and model independent limits on the production cross-section times
branching ratio squared for various new physics processes are presented.
Assuming a 100% branching ratio for the decay of a right-handed charged slepton
to a charged lepton and the lightest neutralino, we exclude at 95% CL:
right-handed smuons with masses below 65 GeV for smuon - neutralino mass
differences greater than 2 GeV and right-handed staus with masses below 64 GeV
for stau - neutralino mass differences greater than 10 GeV. Right-handed
selectrons are excluded at 95% CL for masses below 77 GeV for selectron -
neutralino mass differences greater than 5 GeV within the framework of the
Minimal Supersymmetric Standard Model assuming mu < -100 GeV and tan{beta} =
1.5.


title: A Compact Beam Stop for a Rare Kaon Decay Experiment

abstract:
  We describe the development and testing of a novel beam stop for use in a
rare kaon decay experiment at the Brookhaven AGS. The beam stop is located
inside a dipole spectrometer magnet in close proximity to straw drift chambers
and intercepts a high-intensity neutral hadron beam. The design process,
involving both Monte Carlo simulations and beam tests of alternative beam-stop
shielding arrangements, had the goal of minimizing the leakage of particles
from the beam stop and the resulting hit rates in detectors, while preserving
maximum acceptance for events of interest. The beam tests consisted of
measurements of rates in drift chambers, scintilation counter hodoscopes, a gas
threshold Cherenkov counter, and a lead glass array. Measurements were also
made with a set of specialized detectors which were sensitive to low-energy
neutrons, photons, and charged particles. Comparisons are made between these
measurements and a detailed Monte Carlo simulation.


title:
Measurement of the lepton charge asymmetry in W-boson decays produced in
  p-pbar collisions

abstract:
  We describe a measurement of the charge asymmetry of leptons from W boson
decays in the rapidity range 0<|y_l|<2.5 using W --> enu, munu events from
110+/-7 pb^{-1}of data collected by the CDF detector during 1992-95. The
asymmetry data constrain the ratio of d and u quark momentum distributions in
the proton over the x range of 0.006 to 0.34 at Q2 \approx M_W^2. The asymmetry
predictions that use parton distribution functions obtained from previously
published CDF data in the central rapidity region (0.0<|y_l|<1.1) do not agree
with the new data in the large rapidity region (|y_l|>1.1).


title:
Experimental study of the decay PHI(1020)--->ETA+GAMMA in multi-photon
  final state

abstract:
  In the SND experiment at VEPP-2M e^+e^- collider the phi(1020) ---> eta+gamma
---> 3pi^0+gamma decay was studied. The branching ratio B(phi--->eta+gamma) =
(1.246 +- 0.025 +- 0.057)% was measured.


title:
Measurement of the Atmospheric Neutrino Induced Muon Flux with the MACRO
  detector

abstract:
  The flux of neutrino-induced muons has been measured with the MACRO detector.
Different event topologies have been detected, due to neutrino interactions in
the apparatus and in the rock below it. The upward-throughgoing muon sample is
the larger one and is generated by neutrinos with an average energy of ~ 100
GeV. The observed upward-throughgoing muons are 26% fewer than expected and the
zenith angle distribution does not fit with the expected one. Assuming neutrino
oscillations, both measurements suggest maximum mixing and Dm2 of a few times
10-3 eV2. The other event categories due to interactions of low-energy
neutrinos (average energy ~ 4 GeV) have been recently studied and the results
of these new analyses are presented for the first time at this workshop. These
data show a regular deficit of observed events in each angular bin, as expected
assuming neutrino oscillations with maximum mixing, in agreement with the
analysis of the upward-throughgoing muona sample.


title:
Multiplicity Dependence of Like-Sign and Opposite-Sign Correlations in
  $\bar{p}p$ Reactions

abstract:
  Discussions about Bose-Einstein correlations between decay products of
coproduced W-bosons again raise the question about the behaviour of
correlations if several strings are produced. This is studied by the
multiplicity dependence of correlation functions of particle pairs with
like-sign and opposite-sign charge in $\bar{p}p$ reactions at $\sqrt{s} = 630$
GeV.


title:
ZEUS Results on the Measurement and Phenomenology of $F_2$ at Low x and
  Low Q^2

abstract:
  Measurements of the proton structure function $F_2$ for $0.6 < Q^2 < 17
{GeV}^2$ and $1.2 \times 10^{-5} < x <1.9 \times 10^{-3}$ from ZEUS 1995
shifted vertex data are presented. From ZEUS $F_2$ data the slopes $dF_2/d\ln
Q^2$ at fixed $x$ and $d\ln F_2/d\ln(1/x)$ for $x < 0.01$ at fixed $Q^2$ are
derived. For the latter E665 data are also used. The transition region in $Q^2$
is explored using the simplest non-perturbative models and NLO QCD. The data at
very low $Q^2$ $\leq 0.65 {GeV}^2$ are described successfully by a combination
of generalised vector meson dominance and Regge theory. From a NLO QCD fit to
ZEUS data the gluon density in the proton is extracted in the range $3\times
10^{-5} < x < 0.7$. Data from NMC and BCDMS constrain the fit at large $x$.
Assuming the NLO QCD description to be valid down to $Q^2\sim 1 {GeV}^2$, it is
found that the $q\bar{q}$ sea distribution is still rising at small $x$ and the
lowest $Q^2$ values whereas the gluon distribution is strongly suppressed.


title:
Study of Photo-Nuclear Interaction of muons in rock with the MACRO
  experiment

abstract:
  We present first results about the measurement of the characteristics of
charged hadrons production by atmospheric muons in the rock above MACRO.
Selection criteria which allow to discriminate hadron cascades from e.m.
showers generated by muons are described. A comparison between the measured
rate with that expected from a Monte Carlo simulation which treats the process
as dominated by photo-nuclear interaction is presented. These data can be used
to validate such models aiming to the evaluation of hadron background from
cosmic muons in different experimental environments.


title: The Search for Neutrino Oscillations numubar->nuebar with KARMEN

abstract:
  The neutrino experiment KARMEN is situated at the beam stop neutrino source
ISIS. It provides numu's, nue's and numubar's in equal intensities from the pi+
mu+ decay at rest (DAR). The oscillation channel numub->nueb is investigated in
the appearance mode with a 56t liquid scintillation calorimeter at a mean
distance of 17.7m from the nu source looking for p(nue,e+)n reactions. The
cosmic induced background for this oscillation search could be reduced by a
factor of 40 due to an additional veto counter installed in 1996. In the data
collected through 1997 and 1998 no potential oscillation event was observed.
Using a unified approach to small signals this leads to an upper limit for the
mixing angle of sin**2(2t) < 1.3x10^{-3} (90%CL) at large Dm**2. The excluded
area in (sin**2(2t),Dm**2) covers almost entirely the favored region defined by
the LSND numub->nueb evidence.


title:
The Estimation of the Effective Centre of Mass Energy in q-qbar-gamma
  Events from DELPHI

abstract:
  The photon radiation in the initial state lowers the energy available for the
e$^+$e$^-$ collisions; this effect is particularly important at LEP2 energies
(above the mass of the Z boson). Being aligned to the beam direction, such
initial state radiation is mostly undetected. This article describes the
procedure used by the DELPHI experiment at LEP to estimate the effective
centre-of-mass energy in hadronic events collected at energies above the Z
peak. Typical resolutions ranging from 2 to 3 GeV on the effective
center-of-mass energy are achieved, depending on the event topology.


title: Coloron Limits using the D0 Dijet Angular Distribution

abstract:
  The D0 dijet angular distribution is used to place limits on
flavor--universal colorons. Models with M_c / cot{theta} < 759 GeV/c^2 are
excluded at the 95% confidence level.


title: Evidence of the PHI(1020)--->ETA+PI0+GAMMA Decay

abstract:
  Signal of the rare radiative decay PHI--->ETA+PI0+GAMMA was observed in the
SND experiment at VEPP-2M electron-positron collider.The result is based on the
analysis of data, corresponding to a total integrated luminosity of 4 pb^{-1},
or 8x10^6 PHI mesons produced. The measured branching ratio of
PHI--->ETA+PI0+GAMMA decay is equal to (0.83+-0.23)x10^{-4}.


title: Top Quark Physics at the Tevatron

abstract:
  The discovery of the top quark in 1995, by the CDF and D0 collaborations at
the Fermilab Tevatron, marked the dawn of a new era in particle physics. Since
then, enormous efforts have been made to study the properties of this
remarkable particle, especially its mass and production cross section. In this
article, we review the status of top quark physics as studied by the two
collaborations using the p-pbar collider data at sqrt(s) = 1.8 TeV. The
combined measurement of the top quark mass, m_t = 173.8 +- 5.0 GeV/c^2, makes
it known to a fractional precision better than any other quark mass. The
production cross sections are measured as sigma (t-tbar) = 7.6 -1.5 +1.8 pb by
CDF and sigma (t-tbar) = 5.5 +- 1.8 pb by D0. Further investigations of t-tbar
decays and future prospects are briefly discussed.


title: First Observation of the Decay $\tau^{-}\to K^{*-}\eta\nu_{\tau}$

abstract:
  Using data recorded by the CLEO-II detector at CESR, we report the first
measurement of the branching fraction for the decay of $\tau^-$ into
$K^{*-}\eta \nu_{\tau}$. The measured branching fraction is (2.9 +- 0.8 +- 0.4)
$10^{-4}$. We also measure the inclusive branching fractions without requiring
the $K^*$ resonance: $\tau^-$ into $K_S \pi^- \eta \nu_{\tau}$, $\tau^-$ into
$K^- \pi^0 \eta \nu_{\tau}$. The measured branching fractions are (1.10 +- 0.35
+- 0.11) $10^{-4}$, (1.77 +- 0.56 +- 0.71) $10^{-4}$ respectively.


title: Experiments at VEPP-2M with SND detector

abstract:
  Short overview of experiments with SND detector at VEPP-2M e^+e^- collider in
the energy range 2E = 400 - 1400 MeV and preliminary results of data analysis
are presented.


title:
Global Anisotropy of Space and experimental investigation of changes in
  beta-decay count rate of radioactive elements

abstract:
  The results of experimental investigations of changes in beta-decay count
rate of radioactive elements, are presented, and an explanation of those on the
base of a new physical conception of forming the observed three-dimensional
space from a finite set of one-dimensional discrete vectorial objects (byuons),
containing the cosmological vectorial potential, a new fundamental vectorial
constant, is given. In the theory, the vector direction corresponds with that
of the axis of Universe rotation being discussed in literature.


title:
Determination of the Deep Inelastic Contribution to the Generalised
  Gerasimov-Drell-Hearn Integral for the Proton and Neutron

abstract:
  The virtual photon absorption cross section differences [sigma_1/2-sigma_3/2]
for the proton and neutron have been determined from measurements of polarised
cross section asymmetries in deep inelastic scattering of 27.5 GeV
longitudinally polarised positrons from polarised 1H and 3He internal gas
targets. The data were collected in the region above the nucleon resonances in
the kinematic range nu < 23.5 GeV and 0.8 GeV**2 < Q**2 < 12 GeV**2. For the
proton the contribution to the generalised Gerasimov-Drell-Hearn integral was
found to be substantial and must be included for an accurate determination of
the full integral. Furthermore the data are consistent with a QCD
next-to-leading order fit based on previous deep inelastic scattering data.
Therefore higher twist effects do not appear significant.


title:
Probing Hard Color-Singlet Exchange in ppbar Collisions at root-s=630
  GeV and 1800 GeV

abstract:
  We present results on dijet production via hard color-singlet exchange in
proton-antiproton collisions at root-s = 630 GeV and 1800 GeV using the DZero
detector. The fraction of dijet events produced via color-singlet exchange is
measured as a function of jet transverse energy, separation in pseudorapidity
between the two highest transverse energy jets, and proton-antiproton
center-of-mass energy. The results are consistent with a color-singlet fraction
that increases with an increasing fraction of quark-initiated processes and
inconsistent with two-gluon models for the hard color-singlet.


title: NOE, a Neutrino Oscillation Experiment at Gran Sasso Laboratory

abstract:
  The project of a large underground experiment (NOE) devoted to long baseline
neutrino oscillation measurement is presented. The apparatus is composed by
calorimetric modules interleaved with TRD modules and has been optimized to be
sensitive in the region of sin2 2theta and Dm2 suggested by the atmospheric
neutrino oscillation signal.


title: Properties of Gluon and Quark Jets

abstract:
  Recent developments and results on the comparison of gluon to quark jets are
discussed. A most important topic is the introduction of explicit energy scales
of the jets. The scaling violation of the fragmentation function and the
increase of the multiplicity with scale is shown to be directly proportional to
the corresponding gluon or quark colour factor. The ratio of the hadron
multiplicity in gluon to quark jets is understood to be smaller than the colour
factor ratio due to differences in the fragmentation of the leading quark or
gluon. Novel algorithms to reconstruct the colour portraits or the colour flow
of an event are presented.


title: A Summary of Recent Color Coherence Results

abstract:
  Recent experimental results on color coherence phenomena from e+e-, ep, and
ppbar collisions are presented. The data are compared to analytic perturbative
QCD calculations based on the modified leading logarithm approximation and the
local parton hadron duality hypothesis.


title: Neutrino telescopes under the ocean: The case for ANTARES

abstract:
  Neutrino telescopes offer an alternative way to explore the Universe. Several
projects are in operation or under construction. A detector under the ocean is
very promising because of the very accurate angular resolution that it
provides. The ANTARES project is intended to demonstrate the feasibilty of such
a detector.


title:
The Concurrent Track Evolution Algorithm: Extension for Track Finding in
  the Inhomogeneous Magnetic Field of the HERA-B Spectrometer

abstract:
  The Concurrent Track Evolution method, which was introduced in a previous
paper (DESY 97-054), has been further explored by applying it to the
propagation of track candidates into an inhomogeneous magnetic field volume
equipped with tracking detectors, as is typical for forward B spectrometers
like HERA-B or LHCb. Compared to the field-free case, the method was extended
to three-dimensional propagation, with special measures necessary to achieve
fast transport in the presence of a fast-varying magnetic field. The
performance of the method is tested on HERA-B Monte Carlo events with full
detector simulation and a realistic spectrometer geometry.


title:
Search for New Particles Decaying to b bbar in p pbar Collisions at
  sqrt{s}=1.8 TeV

abstract:
  We have used 87 pb^-1 of data collected with the Collider Detector at
Fermilab to search for new particles decaying to b bbar. We present
model-independent upper limits on the cross section for narrow resonances which
excludes the color-octet technirho in the mass interval 350 < M < 440 GeV/c^2.
In addition, we exclude topgluons, predicted in models of topcolor-assisted
technicolor, of width Gamma = 0.3 M in the mass range 280 < M < 670 GeV/c^2, of
width Gamma = 0.5 M in the mass range 340 < M < 640 GeV/c^2, and of width Gamma
= 0.7 M in the mass range 375 < M < 560 GeV/c^2.


title:
A High Statistics Search for Electron-Neutrino --> Tau-Neutrino
  Oscillations

abstract:
  We present new limits on nu_e to nu_tau and nu_e to nu_sterile oscillations
by searching for electron neutrino dissappearance in the high-energy wide-band
CCFR neutrino beam. Sensitivity to nu_tau appearance comes from tau decay modes
in which a large fraction of the energy deposited is electromagnetic. The beam
is composed primarily of muon neutrinos but this analysis uses the 2.3%
electron neutrino component of the beam. Electron neutrino energies range from
30 to 600 GeV and flight lengths vary from 0.9 to 1.4 km. This limit improves
the sensitivity of existing limits and obtains a lowest 90% confidence upper
limit in sin**2(2*alpha) of 9.9 x 10**(-2) at delta-m**2 of 125 eV**2.


title: Tagging High Energy Photons in the H1 Detector at HERA

abstract:
  Measures taken to extend the acceptance of the H1 detector at HERA for
photoproduction events are described. These will enable the measurement of
electrons scattered in events in the high y range 0.85 < y < 0.95 in the 1998
and 1999 HERA run period. The improvement is achieved by the installation of an
electromagnetic calorimeter, the ET8, in the HERA tunnel close to the electron
beam line 8 m downstream of the H1 interaction point in the electron direction.
The ET8 will allow the study of tagged gamma p interactions at centre-of-mass
energies significantly higher than those previously attainable. The calorimeter
design and expected performance are discussed, as are results obtained using a
prototype placed as close as possible to the position of the ET8 during the
1996 and 1997 HERA running.


title: The AMANDA Neutrino Telescope

abstract:
  With an effective telescope area of order $10^4$ m$^2$ for TeV neutrinos, a
threshold near $\sim$50 GeV and a pointing accuracy of 2.5 degrees per muon
track, the AMANDA detector represents the first of a new generation of high
energy neutrino telescopes, reaching a scale envisaged over 25 years ago. We
describe early results on the calibration of natural deep ice as a particle
detector as well as on AMANDA's performance as a neutrino telescope.


title: Measurement of the form-factor ratios for D+ --> K* l nu

abstract:
  The form factor ratios rv=V(0)/A1(0), r2=A2(0)/A1(0) and r3=A3(0)/A1(0) in
the decay D+ --> K* l nu, K* -->K-pi+ have been measured using data from charm
hadroproduction experiment E791 at Fermilab. From 3034 (595) signal
(background) events in the muon channel, we obtain rv=1.84+-0.11+-0.09,
r2=0.75+-0.08+-0.09 and, as a first measurement of r3, we find 0.04+-0.33
+-0.29. The values of the form factor ratios rv and r2 measured for the muon
channel are combined with the values of rv and r2 that we have measured in the
electron channel. The combined E791 results for the muon and electron channels
are rv=1.87+-0.08+-0.07 and r2=0.73+-0.06+-0.08.


title:
Enhancing Squark/Leptoquark Production by Increasing the HERA Beam
  Energies

abstract:
  The cross section for production of R-parity violating squarks ($\tilde{q}$)
or leptoquarks ($LQ$) with masses above 200 GeV by positron-proton scattering
at HERA can be substantially increased by a moderate increase of the beam
energies. If, for example, the positron energy is raised from 27.5 to 32.5 GeV
and the proton energy from 820 to 1000 GeV, the $\tilde{q}/LQ$ production cross
section for masses of 200 - 230 GeV increases by a factor of about 2-6 and the
search range for $\tilde{q}/LQ$ is extended by about 40 GeV to masses of 270 -
280 GeV. In this report event yields are presented for beam energies in the
range $E_e = 27.5-35 GeV$ and $E_p = 820-1100 GeV$. Also presented is the rate
of background events expected from Standard Model neutral and charged current
$e^{\pm}p$ scattering.


title: Forward Jet and Particle Production at HERA

abstract:
  Single particles and jets in deeply inelastic scattering at low x are
measured with the H1 detector in the region away from the current jet and
towards the proton remnant, known as the forward region. Hadronic final state
measurements in this region are expected to be particularly sensitive to QCD
evolution effects. Jet cross-sections are presented as a function of Bjorken-x
for forward jets produced with a polar angle to the proton direction, theta, in
the range 7 < theta < 20 degrees. Azimuthal correlations are studied between
the forward jet and the scattered lepton. Charged and neutral single particle
production in the forward region are measured as a function of Bjorken-x, in
the range 5 < theta < 25 degrees, for particle transverse momenta larger than 1
GeV. QCD based Monte Carlo predictions and analytical calculations based on
BFKL, CCFM and DGLAP evolution are compared to the data. Predictions based on
the DGLAP approach fail to describe the data, except for those which allow for
a resolved photon contribution.


title:
Correlations between D and $\bar{D}$ mesons produced in 500 GeV/c
  $\pi^-$-nucleon interactions

abstract:
  We present a study of correlations between D and $\bar{D}$ mesons produced in
500 GeV/$c$ $\pi^-$-nucleon interactions, based on data from experiment E791 at
Fermilab. We have fully reconstructed $791 \pm 44$ charm meson pairs to study
correlations between the transverse and longitudinal momenta of the two D
mesons and the relative production rates for different types of D meson pairs.
We see slight correlations between the longitudinal momenta of the D and the
$\bar D$, and significant correlations between the azimuthal angle of the D and
the $\bar D$. The experimental distributions are compared to a
next-to-leading-order QCD calculation and to predictions of the {\sc
Pythia/Jetset} Monte Carlo event generator. We observe less correlation between
transverse momenta and different correlations between longitudinal momenta than
these models predict for the default values of the model parameters. Better
agreement between data and theory might be achieved by tuning the model
parameters or by adding higher order perturbative terms, thus contributing to a
better understanding of charm production.
  The relative production rates for the four sets of charm pairs,
$D^0\bar{D}^{0}$, $D^0D^-$, $D^+\bar{D}^{0}$, $D^+D^-$, as calculated in the
{\sc Pythia/Jetset} event generator with the default parameters, agree with
data as far as the relative ordering, but predict too many $D^+\bar{D}^{0}$
pairs and too few $D^+D^-$ pairs.


title: B+, B0d and b-baryon Lifetimes

abstract:
  We review recent B+, B0d and b-baryon lifetime measurements performed by the
LEP, SLD and CDF collaborations. Lifetime ratios of tau(B+) / tau(B0d) = 1.070
+/- 0.027 and tau(b baryon) / tau(B0d) = 0.77 +/- 0.04 are obtained using all
existing measurements. The ratio between charged and neutral B meson lifetimes
is in good agreement with theory but the ratio between b-baryon and B meson
lifetimes remains somewhat lower than expected.


title:
Search for Chargino and Neutralino Production at sqrt{s} = 181-184 GeV
  at LEP

abstract:
  A search for charginos and neutralinos, predicted by supersymmetric theories,
has been performed using a data sample of 57 pb-1 at centre-of-mass energies of
181-184 GeV taken with the OPAL detector at LEP. No evidence for chargino or
neutralino production has been found. Upper limits on chargino and neutralino
pair production cross-sections are obtained as a function of the chargino mass,
the lightest neutralino mass, and the second lightest neutralino mass. For
large chargino masses the limits have been improved with respect to the
previous analyses at lower centre-of-mass energies. Exclusion regions at 95%
confidence level of parameters of the Constrained Minimal Supersymmetric
Standard Model are determined for the case of a large universal scalar mass,
m_0, implying heavy scalar fermions, and for the case of a small m_0 resulting
in light scalar fermions and giving the worst-case limits. Within this
framework and for the lightest chargino-neutralino mass difference greater than
5 GeV the 95% C.L. lower limits on the lightest chargino mass for m_0 = 500 GeV
are 90.0 and 90.2 GeV for tan(beta) = 1.5 and 35 respectively. These limits for
all m_0 (the worst-case) are 69.1 and 65.2 GeV for tan(beta) = 1.5 and 35
respectively. Exclusion regions are also presented for neutralino masses,
including an absolute lower limit at 95% C.L. for the mass of the lightest
neutralino of 30.1 GeV for m_0 = 500 GeV (24.2 GeV for all m_0), with
implications for experimental searches for the lightest neutralino as a dark
matter candidate.


title:
Atmospheric neutrino results from Super-Kamiokande and Kamiokande -
  Evidence for nu_mu oscillations -

abstract:
  New atmospheric neutrino results from Super-Kamiokande are presented. Results
from Kamiokande on upward going muons are also presented. All these data,
together with the Kamiokande atmospheric neutrino data give evidence for
neutrino oscillations. Two flavor nu_mu <-> nu_tau oscillations, with large
sin^2(2theta) and Delta-m^2 in the region of 10^-3 to 10^-2, explain all these
data.


title: A Measurement of Rb using a Double Tagging Method

abstract:
  The fraction of Z to bbbar events in hadronic Z decays has been measured by
the OPAL experiment using the data collected at LEP between 1992 and 1995. The
Z to bbbar decays were tagged using displaced secondary vertices, and high
momentum electrons and muons. Systematic uncertainties were reduced by
measuring the b-tagging efficiency using a double tagging technique. Efficiency
correlations between opposite hemispheres of an event are small, and are well
understood through comparisons between real and simulated data samples. A value
of Rb = 0.2178 +- 0.0011 +- 0.0013 was obtained, where the first error is
statistical and the second systematic. The uncertainty on Rc, the fraction of Z
to ccbar events in hadronic Z decays, is not included in the errors. The
dependence on Rc is Delta(Rb)/Rb = -0.056*Delta(Rc)/Rc where Delta(Rc) is the
deviation of Rc from the value 0.172 predicted by the Standard Model. The
result for Rb agrees with the value of 0.2155 +- 0.0003 predicted by the
Standard Model.


title:
A measurement of the branching fractions of the f1(1285) and f1(1420)
  produced in central pp interactions at 450 GeV/c

abstract:
  A study of the f1(1285) and f1(1420) produced in central pp interactions has
been performed. For the first time in a single experiment the branching
fractions of both mesons in all major decay modes have been determined. Both
the f1(1285) and f1(1420) are consistent with being produced by double Pomeron
exchange.


title: Performance of the Electromagnetic Calorimeter of the HERMES Experiment

abstract:
  The performance of the electromagnetic calorimeter of the HERMES experiment
is described. The calorimeter consists of 840 radiation resistant F101
lead-glass counters. The response to positrons up to 27.5 GeV, the comparison
between the measured energy and the momentum reconstructed from tracking,
long-term stability, hadron rejection and neutral meson invariant mass
reconstruction are shown.


title:
Evaluation of the LEP Centre-of-Mass Energy Above the W-Pair Production
  Threshold

abstract:
  Knowledge of the beam energy at LEP2 is of primary importance to set the
absolute energy scale for the measurement of the W-boson mass. The beam energy
above 80 GeV is derived from continuous measurements of the magnetic bending
field by 16 NMR probes situated in a number of the LEP dipoles. The
relationship between the fields measured by the probes and the beam energy is
calibrated against precise measurements of the average beam energy between 41
and 55 GeV made using the resonant depolarisation technique. The linearity of
the relationship is tested by comparing the fields measured by the probes with
the total bending field measured by a flux loop. Several further corrections
are applied to derive the the centre-of-mass energies at each interaction
point. The beam energy has been determined with a precision of 25 MeV for the
data taken in 1997, corresponding to a relative precision of 2.7x 10^{-4}.
Prospects for improvements are outlined.


title:
Vector Boson Pair Production and Trilinear Gauge Boson Couplings -
  Results From the Tevatron

abstract:
  Direct measurements of vector boson pair production processes and trilinear
gauge boson couplings have been conducted by the CDF and DO Collaborations.
Preliminary results from searches for anomalous WW/WZ->muon-neutrino-jet-jet
and WZ->e-e-e-neutrino production are presented. 95% CL anomalous coupling
limits from previously published DO results are -0.20 < lambda < 0.20 (Delta
kappa=0) and -0.30 < Delta kappa < 0.43 (lambda=0) for Lambda=2000 GeV where
the WWgamma couplings are assumed to equal the WWZ couplings. Combined DO + LEP
experiment anomalous coupling limits are presented for the first time. 95% CL
limits are -0.16<lambda(gamma)< 0.10 (Delta kappa=0) and -0.15 < Delta
kappa(gamma) < 0.41 (lambda=0) under the assumption that the couplings are
related by the ``HISZ'' constraints. 95% CL anomalous ZZg and Zgg coupling
limits from DO are |h(30)^Z|<0.36 (h(40)^Z=0) and |h(40)^Z|<0.05 (h(30)^Z=0)
for Lambda=750 GeV. CDF reports the first observation of a ZZ event. Prospects
for Run II are discussed.


title: First Observation of the Rare Decay Mode K-long -> e+ e-

abstract:
  In an experiment designed to search for and study very rare two-body decay
modes of the K-long, we have observed four examples of the decay K-long -> e+
e-, where the expected background is 0.17+-0.10 events. This observation
translates into a branching fraction of 8.7^{+5.7}_{-4.1} X 10^{-12},
consistent with recent theoretical predictions. This result represents by far
the smallest branching fraction yet measured in particle physics.


title: Atmospheric neutrino induced muons in the MACRO detector

abstract:
  A measurement of the flux of neutrino-induced muons using the MACRO detector
is presented. Different event topologies, corresponding to different neutrino
parent energies can be detected. The upward throughgoing muon sample is the
larger event sample. The observed upward-throughgoing muons are 26% fewer than
expected and the zenith angle distribution does not fit with the expected one.
Assuming neutrino oscillations, both measurements suggest maximum mixing and
Dm2 of a few times 10-3 eV2. The other samples are due to the internally
produced events and to upward-going stopping muons. These data show a regular
deficit of observed events in each angular bin, as expected assuming neutrino
oscillations with maximum mixing, in agreement with the analysis of the
upward-throughgoing muon sample.


title: Gas electron multiplier: performance and possibilities

abstract:
  The gas electron multiplier produced with the polyimide film 100 um thick.
The maximum gas gain obtained with gas mixture Ar/CH4(91/9) was 5000. No
decrease of gas gain with rates up to 2\cdot10^4 1/(mm^2 s) was observed. The
possibility of operation of GEM with and without MSGC is discussed


title:
QCD Tests Using $b\bar{b}g$ Events and a New Measurement of the B-Hadron
  Energy Distribution

abstract:
  We present new studies of 3-jet final states from hadronic $Z^0$ decays
recorded by the SLD experiment, in which jets are identified as quark,
antiquark or gluon. Our gluon energy spectrum, measured over the full kinematic
range, is consistent with the predictions of QCD, and we derive a limit on an
anomalous chromomagnetic $bbg$ coupling. We measure the parity violation in
$Z^0$ decays into $b\bar{b}g$ to be consistent with the predictions of
electroweak theory and QCD, and perform new tests of T- and CP-conservation at
the $bbg$ vertex. We also present a new technique for reconstructing the energy
of a $B$ hadron using the set of charged tracks attached to a secondary vertex.
The $B$ hadron energy spectrum is measured over the full kinematic range,
allowing improved tests of predictions for the shape of the spectrum. The
average scaled energy is measured to be $ = 0.719 \pm 0.005 (stat.)$
(Preliminary).


title: Final States in Photon-Photon and Photon-Proton Interactions

abstract:
  The total hadronic photon-photon cross-section measured by L3 and OPAL and
the apparent discrepancy between the results are discussed. OPAL measurements
of jet and charged hadron production in photon-photon scattering and
preliminary H1 results on neutral pion production in photon-proton scattering
are also presented. The mechanism of baryon number transfer in photon-proton
interactions at HERA has been studied for the first time by H1.


title: Search for Rare Particles with the MACRO Detector

abstract:
  We report on the search for Rare Particles (Magnetic Monopoles, Nuclearites,
Weakly Interacting Massive Particles and Lightly Ionizing Particles) with the
MACRO detector. For magnetic monopoles (the main goal of the experiment) our
limit is about 0.4 times the Parker bound for monopole velocities between
10^{-4} and 10^{-1}.


title: Study of the reaction pi- Be --> omega pi- pi0 Be

abstract:
  The results of patial wave analysis of the omega pi- pi0 system, produced in
the reaction pi- Be --> pi+ 2pi- 2pi0 Be at beam momentum of 37 GeV are
presented. An indication of the resonant type structure with mass near 1.74 GeV
and JpMetha=0-0+ in the omega rho- system was found. The decay branching ratio
of a2(1320)- to omega pi- pi0 was measured. A wave with JpMetha=2+1+ shows a
broad bump at M near 1.7 GeV. The decays pi2(1670)- --> omega rho- and
a4(2040)- --> omega rho- were observed for the first time. The bump in the
b1(1235)pi wave with exotic quantum numbers Jpc=1-+ at M near 1.7 GeV was
observed.


title:
A simulation code to assist designing space missions of the Airwatch
  type

abstract:
  The design of an Airwatch type space mission can greatly benefit from a
flexible simulation code for establishing the values of the main parameters of
the experiment. We present here a code written for this purpose. The cosmic ray
primary spectrum at very high energies, the atmosphere modelling, the
fluorescence yield, the photon propagation and the detector response are taken
into account in order to optimize the fundamental design parameters of the
experiment, namely orbit height, field of view, mirror radius, number of pixels
of the focal plane, threshold of photo-detection. The optimization criterion
will be to maximize counting rates versus mission cost, which imposes limits
both on weight and power consumption. Preliminary results on signals with
changing energy and zenith angle of incident particles are shown.


title:
Combined Limits on First Generation Leptoquarks from the CDF and D0
  Experiments

abstract:
  We have combined recently published leptoquark results from the CDF and D0
Collaborations which yielded 95% CL lower limits on the first generation scalar
leptoquark mass of 213 GeV and 225 GeV, respectively, under assumption of 100%
branching fraction of the leptoquark decay into the eq channel. The combined
limit from the two experiments is 242 GeV. This is the most stringent limit on
the first generation scalar leptoquark mass to date.


title:
Measurement of the Semileptonic Branching Ratio of Charm Hadrons
  Produced in Z to ccbar Decays

abstract:
  The inclusive charm hadron semileptonic branching fractions B(c to e) and B(c
to mu) in Z to ccbar events have been determined using 4.4 million hadronic Z
decays collected with the OPAL detector at LEP. A charm-enriched sample is
obtained by selecting events with reconstructed D*+- mesons. Using leptons
found in the hemisphere opposite that of the D*+- mesons, the semileptonic
branching fractions of charm hadrons are measured to be B(c to e) = 0.103
+-0.009 +0.009 -0.008 and B(c to mu) = 0.090 +-0.007 +0.007 -0.006 where the
first errors are in each case statistical and the others systematic. Combining
these measurements, an inclusive semileptonic branching fraction of charm
hadrons of B(c to l) = 0.095 +-0.006 +0.007 -0.006 is obtained.


title: Atmospheric and Astrophysics Neutrinos with MACRO

abstract:
  MACRO can detect three topologies of neutrino induced events, corresponding
to different parent neutrino energies. The most numerous sample is made of
upward throughgoing muons induced by atmospheric neutrinos of average energy
100 GeV. We have observed less events than expected events and the observed
zenith distribution does not fit the expected one in the no-oscillation
hypothesis, giving a maximum probability of 0.1 percent. Considering the
neutrino (numu-nutau) oscillation hypothesis the best probability (17 percent)
is obtained for maximum mixing and difference of square masses of a few times
10-3 eV2. The other detected samples are due to internally produced events and
upward-going stopping muons, corresponding to an average neutrino energy of
around 4 GeV. The results concerning these lower energy sample show a deficit
and a shape of the angular distributions in agreement with that predicted by
the oscillation model suggested by the higher energy sample. No evidence of a
neutrino signal due to dark matter particles in the direction of the core of
the Earth and of the Sun has been found among the background due to atmospheric
neutrinos and limits have been set. The neutralino hypothesis is investigated
and limits on its mass are given.


title: Observation of the decay mode K_L -> pi^+ pi^- e^+ e^-

abstract:
  We report on results of an experimental search for the K_L -> pi^+ pi^- e^+
e^- decay mode. We found 13.5 +- 4.0 events and determined its branching ratio
to be (4.4 +- 1.3(stat) +- 0.5(syst))*10^{-7}. The result agrees well with the
theoretical prediction.


title: Gamma-gamma, gamma-electron colliders

abstract:
  It is very likely that in 3-4 years the construction of one or two linear
colliders with c.m.s energy up to 0.5--1.5 TeV will be started. Besides e^+e^-
collisions, linear colliders give a unique possibility to study gamma-gamma and
gamma-electron interactions at energies and luminosities comparable to those in
e^+e^- collisions. High energy photons for gamma-gamma and gamma-electron
collisions can be obtained using laser backscattering. These types of
collisions considerably increase the physics potential of linear colliders for
relatively a small incremental cost. This report briefly reviews the physics
goals and possible parameters of gamma-gamma colliders.

categories: hep-ex hep-ph physics.acc-ph physics.optics


title:
Charged Particle Cross Sections in Photoproduction and Extraction of the
  Gluon Density in the Photon

abstract:
  Photoproduction data collected with the H1 detector at HERA in 1994 are used
to study the cross-sections for inclusive charged particle production and the
structure of the photon. The differential cross-sections dsigma/dpT2, for |eta|
< 1 in the HERA laboratory frame, and dsigma/deta for pT > 2 GeV/c and pT > 3
GeV/c have been measured. Model calculations of these cross-sections, based on
perturbative QCD, indicate that the results are sensitive to the parton
densities of the photon as well as to higher order effects, which are
phenomenologically treated by multiple interactions. This sensitivity is
exploited to determine the leading order x_gamma distribution of partons in the
photon using a new method based on high pT charged particles. The gluon content
of the photon is extracted and found to rise with decreasing x_gamma.


title:
Search for Anomalous Photonic Events with Missing Energy in e+e-
  Collisions at Ecm = 130, 136 and 183 GeV

abstract:
  Photonic events with large missing energy have been observed in e+e-
collisions at centre-of-mass energies of 130, 136 and 183 GeV collected in 1997
using the OPAL detector at LEP. Results are presented for event topologies with
a single photon and missing transverse energy or with an acoplanar photon pair.
Cross-section measurements are performed within the kinematic acceptance of
each selection. These results are compared with the expectations from the
Standard Model process e+e- to nunubar + photon(s). No evidence is observed for
new physics contributions to these final states. Using the data at Ecm = 183
GeV, upper limits on sigma(e+e- to X.Y)*BR(X to Y gamma) and sigma(e+e- to
X.X)*BR(X to Y gamma)**2 are derived for the case of stable and invisible Y.
These limits apply to single and pair production of excited neutrinos (X = nu*,
Y = nu), to neutralino production (X = Chi_2^0, Y = Chi_1^0) and to
supersymmetric models in which X = chi_1^0 and Y is a light gravitino.


title: Long baseline neutrino oscillations

abstract:
  The motivation for possible future long baseline neutrino experiments is
discussed. The proposed experiments as well as their physics potential is
reviewed.


title: A Technique of Direct Tension Measurement of a Strung Fine Wire

abstract:
  We present a new technique of direct measurement of wire tensions in wire
chambers. A specially designed circuit plucks the wire using the Lorentz force
and measures the frequency of damped transverse oscillations of the wire. The
technique avoids the usual time-consuming necessity of tuning circuit parameter
to a resonance. It allows a fast and convenient determination of tensions and
is straightforward to implement.


title:
Search for second generation leptoquarks in the dimuon plus dijet
  channel of p-pbar collisions at sqrt{s}=1.8 TeV

abstract:
  We report on a search for second generation leptoquarks (Phi_2) using a data
sample corresponding to an integrated luminosity of 110 pb^{-1} collected at
the Collider Detector at Fermilab. We present upper limits on the production
cross section as a function of Phi_2 mass, assuming that the leptoquarks are
produced in pairs and decay into a muon and a quark with branching ratio beta.
Using a Next-to-Leading order QCD calculation, we extract a lower mass limit of
M_{\Phi_2} > 202 (160) GeV$/c^{2} at 95% confidence level for scalar
leptoquarks with beta=1(0.5).


title: High Rate Performance of Drift Tubes

abstract:
  This article describes calculations and measurements of space charge effects
due to high rate irradiation in high resolution drift tubes. Two main items are
studied: the reduction of the gas gain and changes of the drift time. Whereas
the gain reduction is similar for all gases and unavoidable, the drift time
changes depend on the kind of gas that is used. The loss in resolution due to
high particle rate can be minimized with a suitable gas. This behaviour is
calculable, allowing predictions for new gas mixtures.


title: Study of 3-prong Hadronic $\tau$ Decays with Charged Kaons

abstract:
  Using a sample of 4.7/fb integrated luminosity accumulated with the CLEO-II
detector at the Cornell Electron Storage Ring (CESR), we have measured the
branching fractions of the tau lepton into $K^- h^+ \pi^- \nu_\tau$ and $K^-
K^+ \pi^- \nu_\tau$ relative to $h^- h^+ h^- \nu_\tau; K^- h^+ \pi^-
\pi^0\nu_\tau$ and $K^- K^+ \pi^- \pi^0\nu_\tau$ relative to $h^- h^+ h^- \pi^0
\nu_\tau$. The relative branching fractions are: (5.16+-0.20+-0.50)*$10^{-2}$,
(1.52+-0.14+-0.29)*$10^{-2}$, (2.54+-0.44+-0.39)*$10^{-2}$ and $<0.0154$ at 95%
C.L., respectively. Coupled with additional experimental information, we use
our results to extract information on the structure of three-prong tau decays
to charged kaons.


title: Charmless and Double-Charm B Decays at SLD

abstract:
  We present new results from the study of B decays at SLD: a measurement of
the inclusive double-charm branching fraction in B-hadron decays and a search
for the rare exclusive charmless decays B+ --> Rho0 Pi+(K+) and B+ --> K*0
Pi+(K+). Using a novel technique which consists of counting charged kaons
produced at the secondary (B) vertex and the tertiary (D) vertex, we measure
BR(B-->DDbarX) = 0.188 +- 0.025(stat) +- 0.059(syst). Another technique, based
on the comparison of the charge of the D vertex to the flavor of the B hadron
at production, yields a consistent result. In the search for rare exclusive B+
decays, no candidates were found and competitive branching ratio upper limits
are derived.


title: Scalar quark searches in e^+e^- collisions at sqrt{s} = 181-184 GeV

abstract:
  Searches for scalar top, scalar bottom and degenerate scalar quarks have been
performed with data collected with the ALEPH detector at LEP. The data sample
consists of 57 pb^-1 taken at sqrt{s} = 181-184 GeV. No evidence for scalar
top, scalar bottom or degenerate scalar quarks was found in the channels
tilde{t} --> c chi, tilde{t} --> b l snu, tilde{b} --> b chi, and tilde{q} -->
q chi. From the channel tilde{t} --> c chi a limit of 74 GeV/c^2 has been set
on the scalar top quark mass, independent of the mixing angle. This limit
assumes a mass difference between the stop and the chi in the range 10-40
GeV/c^2. From the channel tilde{t} --> b l snu the mixing-angle-independent
scalar top limit is 82 GeV/c^2, assuming m_stop - m_snu > 10 GeV/c^2. From the
channel tilde{b} --> b chi a limit of 79 GeV/c^2 has been set on the mass of
the supersymmetric partner of the left-handed state of the bottom quark. This
limit is valid for m_sbottom - m_chi > 10 GeV/c^2. From the channel tilde{q}
--> q chi a limit of 87 GeV/c^2 has been set on the mass of supersymmetric
partners of light quarks, assuming five degenerate flavours and the production
of both ``left-handed'' and ``right-handed'' squarks. This limit is valid for
m_squark - m_chi > 5 GeV/c^2.


title: Measurement of the Top Quark Mass with the Collider Detector at Fermilab

abstract:
  We present a new measurement of the top quark mass in $t\bar t$ events in
which both $W$ bosons from top quarks decay into lepton ($e \nu,\mu \nu$).
  We use events collected by the CDF experiment from $p\bar p$ collisions at
\sqrt s=1.8 TeV at the Tevatron collider. We measure a top quark mass of 167.4
\pm 10.3(stat) \pm 4.8(syst) GeV/c^2 from a sample of eight events. We combine
this result with previous CDF measurements in other decay channels to obtain a
mass value of 176.0 \pm 6.5 GeV/c^2.


title: A Search for $\eta'_c$ Production in Photon-Photon Fusion at LEP

abstract:
  A search for the production of the $\eta'_c$ meson, the first radial
excitation of the ground state of charmonium $\eta_c$(2980), in the
photon-photon fusion reaction at LEP has been performed using the data
collected by the DELPHI detector during 1992-1996. No evidence of $\eta'_c$
production is found in the mass region 3520--3800 MeV/c^2. An upper limit for
the ratio of the two-photon widths of the $\eta'_c$ and $\eta_c$ is obtained.


title:
Search for a Technicolor omega_T Particle in Events with a Photon and a
  b-quark Jet at CDF

abstract:
  If the Technicolor omega_T particle exists, a likely decay mode is omega_T ->
gamma pi_T, followed by pi_T -> bb-bar, yielding the signature gamma bb-bar. We
have searched 85 pb^-1 of data collected by the CDF experiment at the Fermilab
Tevatron for events with a photon and two jets, where one of the jets must
contain a secondary vertex implying the presence of a b quark. We find no
excess of events above standard model expectations. We express the result of an
exclusion region in the M_omega_T - M_pi_T mass plane.


title: Study of eta pi- production by pions in the Coulomb field

abstract:
  The production of eta pi - system at low mass by the pi- beam in the Coulomb
field of Be nuclei was studied. The cross section of the reaction pi- Be -->
eta pi- Be was compared to the experimental data on the decay eta --> pi+ pi-
gamma and to the theoretical predictions.


title: Performance of a Prototype CMS Hadron Barrel Calorimeter in a Test Beam

abstract:
  We report on the performance of a prototype CMS Hadron Barrel Calorimeter
(HCAL) module in a test beam. The prototype sampling calorimeter used copper
absorber plates and scintillator tiles with wavelength shifting fibers for
readout. Placing a lead tungstate crystal electromagnetic calorimeter in front
of HCAL affects the linearity and energy resolution of the combined system to
hadrons. The data are used to optimize the choice of total absorber depth,
sampling frequency, and longitudinal readout segmentation.


title: Identified Hadron Production and Light Quark Fragmentation in Z0 Decays

abstract:
  We have measured the differential cross sections for the production of
$\pi^{+}$, $K^{+}$, $K^{0}$, $K^{*0}$, $\phi$, p, $\Lambda$ and their
corresponding antiparticles in separate samples of flavor-tagged $Z^{0}\to$
light-flavor ($u\bar{u}$, $d\bar{d}$, or $s\bar{s}$), $Z^{0}\to c\bar{c}$ and
$Z^{0}\to b\bar{b}$ events. Clear flavor dependences are observed, and the
results are compared with the predictions of three fragmentation models. We
have also performed a direct measurement of $A_{s}$, the parity-violating
coupling of the $Z^{0}$ to strange quarks, by measuring the
left-right-forward-backward production asymmetry in polar angle of the tagged
$s$ quark. Our preliminary result is $A_{s}$ = $0.82\pm 0.10(stat.)\pm
0.07(syst.)$.


title: Experimental Tests of the Standard Model

abstract:
  Four lectures on experimental test of the standard model presented at the
Advanced Summer Institute on Techniques and Concepts of High Energy Physics.


title:
Observation of Two Narrow States Decaying into $\Xi_{c}^{+}\gamma$ and
  $\Xi_{c}^{0}\gamma$

abstract:
  We report the first observation of two narrow charmed strange baryons
decaying to $\Xi_c^+\gamma$ and $\Xi_c^0\gamma$, respectively, using data from
the CLEO II detector at CESR. We interpret the observed signals as the
$\Xi_c^{+\prime}(c{su})$ and $\Xi_c^{0\prime}(c{sd})$, the symmetric partners
of the well-established antisymmetric $\Xi_c^+(c[su])$ and $\Xi_c^0(c[sd])$.
The mass differences $M(\Xi_c^{+\prime})-M(\Xi_c^+)$ and
$M(\Xi_c^{0\prime})-M(\Xi_c^0)$ are measured to be $107.8\pm 1.7\pm 2.5$ and
$107.0\pm 1.4\pm 2.5 MeV/c^2$, respectively.


title: On the observability of free quarks near their production thresholds

abstract:
  It is proposed to search for free quarks near their production thresholds. If
the current-quark masses for u, d quarks are smaller than the pion mass,
$u\bar{u}$ and $d\bar{d}$ pairs produced below the pion pair threshold, would
not have sufficient energy to hadronize and could be observable. In the case of
large u,d quark masses and also for the heavy quarks, production near threshold
may show hadronization probability $<1$, and lead to free quarks. Searches for
fractional charges in stable matter could be more promising, through
irradiation of samples at energies near the quark pair production thresholds.


title: Physics with two photons at HERA

abstract:
  A survey is presented of the various processes measurable at HERA in which
two photons are involved. Their current experimental status and future
prospects are discussed.


title: On the use of Satellite Television in High Energy Physics

abstract:
  This paper assesses the feasibility of exploiting commercial satellite
television technologies to broadcast video signals and data from major High
Energy Physics facilities to collaborating institutes throughout the world.


title: Ultra Bright LED Light Injection Calibration System for MINOS

abstract:
  We describe here a proposal for a light injection calibration system for the
MINOS detectors based on ultra bright blue LEDs as the light source. We have
shown that these LEDs are bright enough to span over two orders of magnitude in
light intensity, commensurate with that expected in a single scintillator strip
in the MINOS neutrino detectors.


title:
Photon Structure and the Hadronic Final State in Photoproduction
  Processes at ZEUS

abstract:
  Advances in knowledge of the structure of the photon and tests of
perturbative QCD have been made using the increased luminosity with the ZEUS
detector at HERA. Events with a low photon virtuality and two high transverse
energy jets have been studied. Measurements of inclusive dijet and multijet
production are herein compared to Next-to-Leading-Order calculations. In order
to analyse the structure of the photon, dijet production of quasi-real and
virtual photons and dijet production containing $D^{*\pm}$ mesons were
measured.


title:
Extraction of \alpha_s and constraint on the Higgs mass from Electroweak
  fits at the Z resonance

abstract:
  The determination of the Z lineshape parameters at LEP1 is presented and the
value of $\alsmz$ is derived from these measurements. The constraint on the
Higgs mass obtained from a global fit to LEP1 and SLC data is also given.


title: Search for Exclusive Rare Baryonic Decays of $B$ Mesons

abstract:
  We report the results of a search for the rare baryonic decay modes B ->
Lambda Lambdabar, B -> Lambdabar p, B -> Lambdabar p pi, and B -> p pbar using
5.8M BBbar pairs collected with the CLEO detector. We see no statistically
significant signals in any of these modes and set 90% confidence level upper
limits on their branching fractions,
  B(B -> Lambda Lambdabar) < 3.9 \times 10^{-6},
  B(B -> Lambdabar p) < 2.6 \times 10^{-6},
  B(B -> Lambdabar p pi) < 1.3 \times 10^{-5}, and B(B -> p pbar) < 7.0 \times
10^{-6}.


title: Jets and Prompt Photons in Photoproduction at ZEUS

abstract:
  In the ZEUS experiment at HERA, photoproduction processes have been studied
for photon-proton centre-of-mass energies in the range 100 < W_gamma p < 300
GeV and jet transverse energies extending to E_T^jet ~ 70 GeV. The data
contribute to our understanding of QCD dynamics, and also provide new
constraints on the photon's parton density.


title: Search for Higgs Bosons in e^+e^- Colliders

abstract:
  Table of contents 1. Introduction 2. Theory 3. Searches at LEP2 4. Results 5.
Futur colliders 6. Final remarks


title: Measurement of Three-jet Distributions in Photoproduction at HERA

abstract:
  The cross section for the photoproduction of events containing three jets
with a three-jet invariant mass of M_3J > 50 GeV has been measured with the
ZEUS detector at HERA. The three-jet angular distributions are inconsistent
with a uniform population of the available phase space but are well described
by parton shower models and O(alpha alpha_s^2) pQCD calculations. Comparisons
with the parton shower model indicate a strong contribution from initial state
radiation as well as a sensitivity to the effects of colour coherence.


title: Determination of the LEP center-of-mass energy from Zgamma events

abstract:
  Radiative returns to the Z resonance (Zgamma events) provide a method to
determine the centre-of-mass energy of the high energy e+e- colliders and
already at LEP2. The method is applied for the data collected with the ALEPH
detector in 1997 at 181-184 GeV, using e+e- -> gammaZ -> hadrons events.


title: TDC Chip and Readout Driver Developments for COMPASS and LHC-Experiments

abstract:
  A new TDC-chip is under development for the COMPASS experiment at CERN. The
ASIC, which exploits the 0.6 micrometer CMOS sea-of-gate technology, will allow
high resolution time measurements with digitization of 75 ps, and an
unprecedented degree of flexibility accompanied by high rate capability and low
power consumption. Preliminary specifications of this new TDC chip are
presented.
  Furthermore a FPGA based readout-driver and buffer-module as an interface
between the front-end of the COMPASS detector systems and an optical S-LINK is
in development. The same module serves also as remote fan-out for the COMPASS
trigger distribution and time synchronization system. This readout-driver
monitors the trigger and data flow to and from front-ends. In addition, a
specific data buffer structure and sophisticated data flow control is used to
pursue local pre-event building. At start-up the module controls all necessary
front-end initializations.


title: The SELEX Phototube RICH Detector

abstract:
  In this article, construction, operation, and performance of the RICH
detector of Fermilab experiment 781 (SELEX) are described. The detector
utilizes a matrix of 2848 phototubes for the photocathode to detect Cherenkov
photons generated in a 10m Neon radiator. For the central region an N0 of
104/cm, corresponding to 13.6 hits on a beta=1 ring, was obtained. The ring
radius resolution measured is 1.6%.


title: Limits on the Mass of the Tau Neutrino from CLEO

abstract:
  A limit on the mass of the tau neutrino is derived from 4.5x10^6 tau pairs
produced at a center of mass energy of 10.6 GeV. The measurement technique
involves a two-dimensional extended likelihood analysis, including the
dependence of the end-point population on the tau neutrino mass, and allows for
the first time an explicit background contribution. We use the decays of the
tau to five charged pions and a neutrino and to 3 charged pions, 2 neutral
pions and a neutrino to obtain an upper limit of 30 MeV, as well as a
preliminary limit of 31 MeV from the decay of a tau to 3 charged hadrons, a
neutral pi and a neutrino.


title: Measurement of the Sigma^- Charge Radius at SELEX

abstract:
  The charge radii of Sigma^- and pi^- have been determined by direct elastic
scttering on shell electrons. The measurement was performed in the framework of
the SELEX (E781) charm hadroproduction experiment at Fermilab which employs a
600 GeV/c high-intensity Sigma^-/pi^- beam and a 3-stage magnetic spectrometer
covering 0.1 <= x_F <= 1.0. Scattering angles and momenta of both hadron and
electron were measured with high precision using silicon microstrip detectors,
thus allowing for a segmented solid target. Two TRDs provided full particle
identification. A preliminary result for the Sigma^- charge radius for a
four-momentum transfer squared of 0.03 GeV^2/c^2 <= Q^2 <= 0.16 GeV^2/c^2 will
be reported. In a parallel analysis the pi^- charge radius has been determined
for 0.03 GeV^2/c^2 <= Q^2 <= 0.2 GeV^2/c^2, and is found to be consistent with
previous experiments.


title: Charm `in' the Photon

abstract:
  Some recent ZEUS results on the photoproduction of open charm and possible
implications for photon structure are discussed.


title: Search for composite and exotic fermions at LEP 2

abstract:
  A search for unstable heavy fermions with the DELPHI detector at LEP is
reported. Sequential and non-canonical leptons, as well as excited leptons and
quarks, are considered. The data analysed correspond to an integrated
luminosity of about 48 pb^{-1} at an e^+e^- centre-of-mass energy of 183 GeV
and about 20 pb^{-1} equally shared between the centre-of-mass energies of 172
GeV and 161 GeV. The search for pair-produced new leptons establishes 95%
confidence level mass limits in the region between 70 GeV/c^2 and 90 GeV/c^2,
depending on the channel. The search for singly produced excited leptons and
quarks establishes upper limits on the ratio of the coupling of the excited
fermion


title:
Search for lightest neutralino and stau pair production in light
  gravitino scenarios with stau NLSP

abstract:
  Promptly decaying lightest neutralinos and long-lived staus are searched for
in the context of light gravitino scenarios. It is assumed that the stau is the
next to lightest supersymmetric particle (NLSP) and that the lightest
neutralino is the next to NLSP (NNLSP). Data collected with the Delphi detector
at centre-of-mass energies from 161 to 183 \GeV are analysed. No evidence of
the production of these particles is found. Hence, lower mass limits for both
kinds of particles are set at 95% C.L.. The mass of gaugino-like neutralinos is
found to be greater than 71.5 GeV/c^2. In the search for long-lived stau,
masses less than 70.0 to 77.5 \GeVcc are excluded for gravitino masses from 10
to 150 \eVcc . Combining this search with the searches for stable heavy leptons
and Minimal Supersymmetric Standard Model staus a lower limit of 68.5 \GeVcc
may be set for the stau mass


title:
A Search for Heavy Stable and Long-Lived Squarks and Sleptons in e^+ e^-
  Collisions at Energies from 130 to 183 GeV

abstract:
  A search for stable and long-lived heavy charged particles used the data
taken by the DELPHI experiment at energies from 130 to 183 GeV. The Cherenkov
light detected in the Ring Imaging Cherenkov Detector and the ionization loss
measured in the Time Projection Chamber identify heavy particles from masses of
2 to nearly 89 GeV/c^2. Upper limits are given on the production cross-section
and masses of sleptons, free squarks with a charge of $q = \pm 2/3e$ and
hadronizing squarks.


title: Bounds on $\nu_{\mu}$ Oscillations from Atmospheric Neutrinos

abstract:
  A reanalysis of identified muon neutrino interactions from IMB 3 yields
bounds on $\sin^{2}(2 \theta)$ and $\Delta m^{2}$. The limit $\sin^{2}(2
\theta) < 0.72$ is in conflict with the recent announcement of a neutrino mass.


title: Recent Results on Neutrino Oscillations

abstract:
  This article reviews the many new results from neutrino oscillation searches
which were presented at ICHEP '98. Exciting indications of neutrino
oscillations have been seen in the solar neutrino deficit, atmospheric neutrino
deficit and LSND excess. These indications and reported limits on oscillations
are considered. Attempts to develop a theory which addresses all of the
neutrino oscillation data are discussed. Some of the remaining questions and
the future experiments which will help answer these questions are described.


title: Single and Pair Production of Neutral Electroweak Gauge Bosons at LEP

abstract:
  Recent LEP results on single and pair production of neutral electroweak gauge
bosons are reviewed. QED and Electroweak gamma-e Compton scattering at LEP
covers gamma-e center-of-mass energies sqrt{shat} in the range from about 20
GeV to 170 GeV, and leads to single production of on-shell gamma, off-shell
gamma*, and Z bosons, also known as ``Zee'' process. The latter two final
states have been observed for the first time by the OPAL collaboration, while
the measurement of the scattered on-shell gamma's by L3 represents the highest
energies at which QED Compton scattering has been studied so far. These
processes can be used to set limits on excited electrons. Pair production of
gamma* and/or Z at the e+e- center-of-mass energy sqrt{s}=183 GeV has been
studied by the DELPHI, L3, and OPAL collaborations. The combination of these
experiments yields the first significant measurement of Z pair production. With
more statistics at higher energies, interesting limits on anomalous gammaZZ and
ZZZ couplings can be derived from this process.


title:
Observation of a Coherence Length Effect in Exclusive Rho^0
  Electroproduction

abstract:
  Exclusive incoherent electroproduction of the rho^0(770) meson from 1H, 2H,
3He, and 14N targets has been studied by the HERMES experiment at squared
four-momentum transfer Q**2>0.4 GeV**2 and positron energy loss nu from 9 to 20
GeV. The ratio of the 14N to 1H cross sections per nucleon, known as the
nuclear transparency, was found to decrease with increasing coherence length of
quark-antiquark fluctuations of the virtual photon. The data provide clear
evidence of the interaction of the quark- antiquark fluctuations with the
nuclear medium.


title: Neutrino Trident Production from NuTeV

abstract:
  A preliminary analysis of zero hadronic energy dimuon production in the NuTeV
experiment is presented (nu_mu (anti-nu_mu) + N -> nu_mu(anti-nu_mu) + mu^+ +
mu^- + N). The data show a signal in excess of background which is attributed
to neutrino trident production. This excess is consistent with the Standard
Model prediction including electroweak interference. Other sources of
low-hadronic energy dimuon events are also considered.


title:
Measurement of Leading Proton and Neutron Production in Deep Inelastic
  Scattering at HERA

abstract:
  Deep--inelastic scattering events with a leading baryon have been detected by
the H1 experiment at HERA using a forward proton spectrometer and a forward
neutron calorimeter. Semi--inclusive cross sections have been measured in the
kinematic region 2 <= Q^2 <= 50 GeV^2, 6.10^-5 <= x <= 6.10^-3 and baryon p_T
<= MeV, for events with a final state proton with energy 580 <= E' <= 740 GeV,
or a neutron with energy E' >= 160 GeV. The measurements are used to test
production models and factorization hypotheses. A Regge model of leading baryon
production which consists of pion, pomeron and secondary reggeon exchanges
gives an acceptable description of both semi-inclusive cross sections in the
region 0.7 <= E'/E_p <= 0.9, where E_p is the proton beam energy. The leading
neutron data are used to estimate for the first time the structure function of
the pion at small Bjorken--x.


title:
Study of D^{**} and D^{*'} Production in B and C Jets, with the Delphi
  Detector

abstract:
  Using D$^{*+}$ mesons exclusively reconstructed in the DELPHI detector at
LEP, orbital and radial excitations of non strange charmed mesons are studied.
The multiplicities of the two narrow $D^0_1$ and $D^{*0}_2$ orbital excitations
are measured in $Z^0 \to c \bar c$ and $Z^0 \to b \bar b$ decays. Preliminary
results are obtained on the production of broad D$^{**}$ states, using B meson
semi-leptonic decays. A narrow signal of 66 $\pm$ 14 events is observed in the
$(D^{*+} \pi^+ \pi^-)$ final state, interpreted as the first evidence of the
predicted $D^{*'}$ radial excitation.


title: The forward-backward asymmetry for charm quarks at the Z

abstract:
  The data set collected with the ALEPH detector from 1991 to 1995 at LEP has
been analysed to measure the charm forward-backward asymmetry at the Z. Out of
a total of 4.1 million hadronic Z decays, about 36000 high momentum D*+, D+ and
D0 decays were reconstructed, of which 80% originate from Z -> ccbar events...


title: Measurement of the Ds Lifetime

abstract:
  We report the results of a precise measurement of the Ds meson lifetime based
on 1662 +/- 56 fully reconstructed Ds -> phi pi decays, from the charm
hadroproduction experiment E791 at Fermilab. Using an unbinned maximum
likelihood fit, we measure the Ds lifetime to be 0.518 +/- 0.014 +/- 0.007 ps.
The ratio of the measured Ds lifetime to the world average D0 lifetime is 1.25
+/- 0.04. This result differs from unity by six standard deviations, indicating
significantly different lifetimes for the Ds and the D0.


title:
The K0sK0s Final State in Two-Photon Collisions and Some Implications
  for Glueball Searches

abstract:
  The K0sK0s final state in two-photon collisions is studied with the L3
detector at LEP using data at centre of mass energies from 91 GeV to 183 GeV.
The K0sK0s mass spectrum is dominated by the formation of the f_2'(1525) tensor
meson whose two-photon partial width is measured. Clear evidence for
destructive f_2-a_2 interference is observed. No signal is present in the
region around 2.2 GeV. An upper limit for the two-photon partial width times
the K0sK0s branching ratio of the \xi(2230) glueball candidate is then derived.
An enhancement is observed around 1750 MeV. It may be due to the formation of a
radial recurrence of the f_2'(1525) or to the s\bar{s} member of the 0++ meson
nonet.


title: Search for B0s oscillations using inclusive lepton events

abstract:
  A search for B0s oscillations is performed using a sample of semileptonic
b-hadron decays collected by the ALEPH experiment during 1991-1995. Compared to
previous inclusive lepton analyses, the proper time resolution and b-flavour
mistag rate are significantly improved. Additional sensitivity to B0s mixing is
obtained by identifying subsamples of events having a B0s purity which is
higher than the average for the whole data sample. Unbinned maximum likelihood
amplitude fits are performed to derive a lower limit of Deltam_s>9.5ps^-1 at
95% CL. Combining with the ALEPH D-s based analyses yields Deltam_s>9.6ps^-1 at
95% CL.


title:
The Light Front Analysis of pi^{-} Mesons Produced in the Relativistic
  Nucleus-Nucleus Collisions

abstract:
  The light front analysis of pi^{-} mesons in A_{P} (He, C, Mg, O) + A_{T}
(Li,C, Ne, Mg,Cu,Pb) collisions is carried out. The phase space of secondary
pions is naturally divided into two parts in one of which the thermal
equilibration assumption seems to be in a good agreement with data.
Corresponding temperatures are extracted and compared to the results of other
experiments. The dependence of the average temperature T on (A_{P}*A_{T})^{1/2}
is studied.


title:
Modern Status of Neutrino Experiments at the Underground Neutrino
  Laboratory of Kurchatov Institute Near Krasnoyarsk Nuclear Reactor

abstract:
  The investigation of antineutrino-deuteron interaction at Krasnoyarsk reactor
are discussed. The characteristics of the installation ''Deuteron'', present
results and perspectives of Krasnoyarsk neutrino laboratory are presented.


title: Study of D0-Dbar0 mixing and D0 doubly cabibbo-suppressed decays

abstract:
  Using a sample of four million hadronic Z events collected in ALEPH from 1991
to 1995, the decays D*+ -> D0pi^+_s, with D0 decaying to K-pi+ or to K+pi-, are
studied. The relative branching ratio B(D0 -> K+pi-)/B(D0 -> K-pi+) is measured
to be (1.84+-0.59(stat.)+-0.34(syst.))%. The two possible contributions to the
D0 -> K+pi- decay, doubly cabibbo-suppressed decays and D0-Dbar0 mixing, are
disentangled by measuring the proper-time ditribution of the reconstructed
D0's. Assuming no interference between the two processes, the upper limit
obtained on the mixing rate is 0.92% at 95% CL. The possible effect of
interference between the two amplitudes is also assessed.


title: The GENIUS Project - Background and technical studies

abstract:
  The potential of GENIUS as a dark matter detector is discussed. A study was
performed to demonstrate the good behaviour of the proposed detector design of
naked HPGe-crystals in liquid nitrogen. The expected background components were
simulated and are discussed in some detail.With the obtained background GENIUS
could cover a large part of the favoured MSSM parameter-space.


title: The structure of the photon and its interactions

abstract:
  The OPAL experiment at LEP has performed a variety of measurements of
photon-photon and electron-photon scattering at the electron-positron collider
LEP to gain a deeper insight into the structure of the photon and its
interactions. This review presents a summary of these results.


title: Two Photon Physics at a Future Linear Collider

abstract:
  Some general considerations on a future linear collider and selected topics
of two photon physics measurements which can be performed at such a collider
are presented. This review discusses the total photon-photon cross section, jet
cross sections, structure functions, charm production, the BFKL Pomeron,
  $W$ pair production, and Higgs production.


title: Search for Higgs Bosons in e+e- Collisions at 183 GeV

abstract:
  The data collected by the OPAL experiment at sqrts=183 GeV were used to
search for Higgs bosons which are predicted by the Standard Model and various
extensions, such as general models with two Higgs field doublets and the
Minimal Supersymmetric Standard Model (MSSM). The data correspond to an
integrated luminosity of approximately 54pb-1. None of the searches for neutral
and charged Higgs bosons have revealed an excess of events beyond the expected
background. This negative outcome, in combination with similar results from
searches at lower energies, leads to new limits for the Higgs boson masses and
other model parameters. In particular, the 95% confidence level lower limit for
the mass of the Standard Model Higgs boson is 88.3 GeV. Charged Higgs bosons
can be excluded for masses up to 59.5 GeV. In the MSSM, mh > 70.5 GeV and mA >
72.0 GeV are obtained for tan{beta}>1, no and maximal scalar top mixing and
soft SUSY-breaking masses of 1 TeV. The range 0.8 < tanb < 1.9 is excluded for
minimal scalar top mixing and m{top} < 175 GeV. More general scans of the MSSM
parameter space are also considered.


title: Experimental Summary on Hadronic Decays: A TAU98 Review

abstract:
  Selected results on hadronic decays of the tau lepton from the TAU98 Workshop
are reviewed. A comprehensive picture emerges for strange particle branching
fractions, and exploration of resonant substructure of both strange and
non-strange decays is seen to have matured substantially.


title: First Observation of the Decay $B^{0}\to D^{*+}D^{*-}$

abstract:
  We have observed four fully reconstructed B0 -> D*+D*- candidates in 5.8
million Upsilon(4S) -> BBbar decays recorded with the CLEO detector. The
background is estimated to be 0.31 +- 0.10 events. The probability that the
background could produce four or more signal candidates with the observed
distribution among D*+ and D*- decay modes is 1.1 X 10^{-4}. The measured decay
rate, Br(B0 -> D*+D*-) = [6.2 +4.0-2.9 (stat) +- 1.0(syst)] X 10^{-4}, is large
enough for this decay mode to be of interest for the measurement of a
time-dependent CP asymmetry.


title:
W+W- production and triple gauge boson couplings at LEP energies up to
  183 GeV

abstract:
  A study of W-pair production in e+e- annihilations at Lep2 is presented,
based on 877 W+W- candidates corresponding to an integrated luminosity of 57
pb-1 at sqrt(s) = 183 GeV. Assuming that the angular distributions of the
W-pair production and decay, as well as their branching fractions, are
described by the Standard Model, the W-pair production cross-section is
measured to be 15.43 +- 0.61 (stat.) +- 0.26 (syst.) pb. Assuming lepton
universality and combining with our results from lower centre-of-mass energies,
the W branching fraction to hadrons is determined to be 67.9 +- 1.2 (stat.) +-
0.5 (syst.)%. The number of W-pair candidates and the angular distributions for
each final state (qqlnu,qqqq,lnulnu) are used to determine the triple gauge
boson couplings. After combining these values with our results from lower
centre-of-mass energies we obtain D(kappa_g)=0.11+0.52-0.37,
D(g^z_1)=0.01+0.13-0.12 and lambda=-0.10+0.13-0.12, where the errors include
both statistical and systematic uncertainties and each coupling is determined
setting the other two couplings to the Standard Model value. The fraction of W
bosons produced with a longitudinal polarisation is measured to be
0.242+-0.091(stat.)+-0.023(syst.). All these measurements are consistent with
the Standard Model expectations.


title:
Search for High Mass Photon Pairs in p-pbar --> gamma-gamma-jet-jet
  Events at sqrt(s)=1.8 TeV

abstract:
  A search has been carried out for events in the channel p-barp --> gamma
gamma jet jet. Such a signature can characterize the production of a
non-standard Higgs boson together with a W or Z boson. We refer to this
non-standard Higgs, having standard model couplings to vector bosons but no
coupling to fermions, as a "bosonic Higgs." With the requirement of two high
transverse energy photons and two jets, the diphoton mass (m(gamma gamma))
distribution is consistent with expected background. A 90(95)% C.L. upper limit
on the cross section as a function of mass is calculated, ranging from
0.60(0.80) pb for m(gamma gamma) = 65 GeV/c^2 to 0.26(0.34) pb for m(gamma
gamma) = 150 GeV/c^2, corresponding to a 95% C.L. lower limit on the mass of a
bosonic Higgs of 78.5 GeV/c^2.


title: Bose-Einstein Correlations in e+e- to W+W- at 172 and 183 GeV

abstract:
  Bose-Einstein correlations between like-charge pions are studied in hadronic
final states produced by e+e- annihilations at center-of-mass energies of 172
and 183 GeV. Three event samples are studied, each dominated by one of the
processes W+W- to qqlnu, W+W- to qqqq, or (Z/g)* to qq. After demonstrating the
existence of Bose-Einstein correlations in W decays, an attempt is made to
determine Bose-Einstein correlations for pions originating from the same W
boson and from different W bosons, as well as for pions from (Z/g)* to qq
events. The following results are obtained for the individual chaoticity
parameters lambda assuming a common source radius R: lambda_same = 0.63 +- 0.19
+- 0.14, lambda_diff = 0.22 +- 0.53 +- 0.14, lambda_Z = 0.47 +- 0.11 +- 0.08, R
= 0.92 +- 0.09 +- 0.09. In each case, the first error is statistical and the
second is systematic. At the current level of statistical precision it is not
established whether Bose-Einstein correlations, between pions from different W
bosons exist or not.


title:
Progress towards CLEO III: the silicon tracker and the LiF-TEA Ring
  Imaging Cherenkov Detector

abstract:
  We describe the two major components of CLEO III: the Silicon Vertex Detector
and the Ring Imaging Cherenkov Detector (RICH). The Silicon Vertex Detector is
a four layer barrel-style device which spans the radial distance from 2.5 cm to
10.1 cm and covers 93% of the solid angle. It is being constructed using
double-sided silicon sensors read out by front end electronics devices
especially designed for this application. The RICH system consists of LiF
radiators and multiwire proportional chambers containing a mixture of CH4 and
TEA gases. The radiators are both flat and "sawtooth." Results from a test beam
run of final CLEO III RICH modules will be presented, as well as test beam data
on sensors to be employed in the Silicon Vertex Tracker.


title:
Search for the Standard Model Higgs boson at the LEP2 collider near
  sqrt(S) = 183GeV

abstract:
  During 1997 the ALEPH experiment at LEP gathered 57pb^-1 of data at
centre-of- mass energies near 183 GeV. These data are used to look for possible
signals from the production of the Standard Model Higgs boson in the reaction
e+e- -> HZ. No evidence of a signal is found in the data; seven events are
selected, in agreement with the expectation of 7.2 events from background
processes. This observation results in an improved lower limit on the mass of
the Higgs boson: m_H > 87.9GeV/c^2 at 95% confidence level.


title:
Search for supersymmetry with a dominant R-parity violating LQDbar
  couplings in e+e- collisions at centre-of-mass energies of 130GeV to 172 GeV

abstract:
  A search for pair-production of supersymmetric particles under the assumption
that R-parity is violated via a dominant LQDbar coupling has been performed
using the data collected by ALEPH at centre-of-mass energies of 130-172 GeV.
The observed candidate events in the data are in agreement with the Standard
Model expectation. This result is translated into lower limits on the masses of
charginos, neutralinos, sleptons, sneutrinos and squarks. For instance, for
m_0=500 GeV/c^2 and tan(beta)=sqrt(2) charginos with masses smaller than 81
GeV/c^2 and neutralinos with masses smaller than 29 GeV/c^2 are excluded at the
95% confidence level for any generation structure of the LQDbar coupling.


title:
Two topics in multiparticle dyamics at LEP: multiplicity in b-bbar
  events and screwiness at the end of the QCD cascade

abstract:
  This talk deals with two topics in multiparticle dynamics investigated by
means of the DELPHI detector at LEP. Related to the first topic, we have used
the data collected at 183 GeV to measure the average charged particle
multiplicity in $e^+e^- \to b\bar{b}$ events. The result is remarkably in
agreement with QCD predictions, while it is more than two standard deviations
larger than calculations assuming that the multiplicity accompanying the decay
of a heavy quark is independent of the mass of the quark itself. The second
topic deals with a recent theoretical model by Andersson et al., in which soft
gluons order themselves in the form of a helix at the end of the QCD cascades.
In our data at the Z peak, we have found no evidence for such an effect.


title: Heavy Quark Production and Decay: t, b, and onia

abstract:
  This paper summarizes a variety of recent results on heavy quark production
and decay. Considerable progress has been made by CDF and D0 in measuring top
quark production and decay properties. The top quark mass been measured with an
uncertainty that is less than 3%, a relative precision that is better than has
been achieved for other quarks. Measurements of the top production and decay
properties are consistent with the Standard Model predictions, but are
generally limited in precision by the small number of top quark events in the
present data samples. ALEPH and CLEO have measured the branching ratio for the
flavor changing neutral current decay b->s gamma and find good agreement with
the Standard Model. Measurements of b-quark production cross sections in ppbar
collisions by CDF and D0 and in ep collisions by H1 continue to show
discrepancies between theory and experiment. CDF and DELPHI have measured the
b-quark fragmentation fractions with better accuracy than previous
measurements. Finally, measurements of charmonium production by D0, E771, and
L3 are consistent with predictions of the color octet model.