Properties of the eta and eta-prime mesons

Noviembre 7, 2019
De 3:00pm hasta 4:00pm

IFT Seminar Room/Red Room

Specialist level
Sara Collins
U. Regensburg

IFT Seminar Room/Red Room


The eta and eta-prime mesons have been the focus of many theoretical
studies because of their connection to the chiral anomaly of QCD and
their important role in many QCD processes.  In the past, lattice
studies have largely been restricted to determining their masses due
to the computational challenge of evaluating the quark line
disconnected diagrams, with the systematics of the calculations often
not being explored. Recent technical developments now mean matrix
elements relevant for decay form factors and decay constants can be
determined too. I will present results for the four (independent) axial
decay constants of the eta and eta-prime mesons, in addition to their
masses. The analysis is performed on the CLS 2+1 flavour ensembles,
with pion masses ranging from 420 MeV down to the physical mass
point. Four lattice spacings and two distinct approaches to the
physical point in the quark mass plane enable the continuum limit and
chiral interpolation to be performed with care. Results are obtained
for some of the lesser known low energy constants that appear in NLO
large-NcChPT expressions. As a by-product, we test the flavour-singlet
PCAC relation, probing the purely gluonic contribution to the singlet
decay constants.