Tests of Lorentz violation in muon antineutrino to electron antineutrino oscillations (hep-ex/0506067)
L.B. Auerbach, R.L. Burman, D.O. Caldwell, E.D. Church, A.K. Cochran, J.B. Donahue, A.R. Fazely, G.T. Garvey, R. Gunasingha, R.L. Imlay, T. Katori, W.C. Louis, K.L. McIlhany, W.J. Metcalf, G.B. Mills, V.D. Sandberg, D. Smith, I. Stancu, W.H. Strossman, R. Tayloe, M. Sung, W. Vernon, D.H. White, S. Yellin
Oct. 6, 2005 hep-ph, hep-ex
A recently developed Standard-Model Extension (SME) formalism for neutrino oscillations that includes Lorentz and CPT violation is used to analyze the sidereal time variation of the neutrino event excess measured by the Liquid Scintillator Neutrino Detector (LSND) experiment. The LSND experiment, performed at Los Alamos National Laboratory, observed an excess, consistent with neutrino oscillations, of ${\bar\nu}_e$ in a beam of ${\bar\nu}_\mu$. It is determined that the LSND oscillation signal is consistent with no sidereal variation. However, there are several combinations of SME coefficients that describe the LSND data; both with and without sidereal variations. The scale of Lorentz and CPT violation extracted from the LSND data is of order $10^{-19}$ GeV for the SME coefficients $a_L$ and $E \times c_L$. This solution for Lorentz and CPT violating neutrino oscillations may be tested by other short baseline neutrino oscillation experiments, such as the MiniBooNE experiment.
Search for $\pi^0 \to \nu_{\mu}\bar\nu_{\mu}$ Decay in LSND (hep-ex/0310060)
L.B. Auerbach, R.L. Burman, D.O. Caldwell, E.D. Church, A.K. Cochran, J.B. Donahue, A.R. Fazely, G.T. Garvey, R.M. Gunasingha, R.L. Imlay, G. Kahrimanis, W.C. Louis, R. Majkic, A. Malik, K.L. McIlhany, W.J. Metcalf, G.B. Mills, D. Rupnik, V.D. Sandberg, D. Smith, R.F. Somodi, I. Stancu, W.D. Strossman, M. Sung, R. Tayloe, G.J. VanDalen, W. Vernon, N. Wadia, D.H. White, S. Yellin, H. Yi
Oct. 30, 2003 hep-ex
We observe a net beam-excess of $8.7 \pm 6.3$ (stat) $\pm 2.4$ (syst) events, above 160 MeV, resulting from the charged-current reaction of $\nu_{\mu}$ and/or $\bar\nu_{\mu}$ on C and H in the LSND detector. No beam related muon background is expected in this energy regime. Within an analysis framework of $\pi^0 \to \nu_{\mu}\bar\nu_{\mu}$, we set a direct upper limit for this branching ratio of $\Gamma(\pi^0 \to \nu_\mu \bar\nu_\mu) / \Gamma(\pi^0 \to all) < 1.6 \times 10^{-6}$ at 90% confidence level.