München 2019 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 40: Hadron Structure and Spectroscopy VI

HK 40.1: Group Report

Wednesday, March 20, 2019, 16:30–17:00, HS 13

The quark-mass dependence of light meson masses and decay constants — •Xiao-Yu Guo¹ and Matthias F.M. Lutz^1,2 — ¹GSI Helmholtzzentrum, Planckstr. 1, 64291 Darmstadt, Germany — ²Technische Universität Darmstadt, D-64289 Darmstadt, Germany

We study the dependence of light meson masses and decay constants on the up, down and strange quark masses. The role of dynamical vector meson degrees of freedom is scrutinized in terms of an effective chiral Lagrangian based on the hadrogenesis conjecture. It is illustrated that an order-by-order renormalizable effective field theory arises once specific conditions on the low-energy constants are imposed. At the one-loop level, we derive the chiral corrections to the self-energies of the Goldstone bosons and vector mesons as well as the decay constants of the Goldstone bosons. According to the chiral formula, we scrutinize QCD lattice data on the masses of the light vector mesons from PACS-CS, QCDSF-UK and HSC. Particular attention is paid to the ω−φ mixing phenomenon, which is demonstrated to show a strong mass dependence. Applying the low-energy constants determined accordingly, further implications are computed on the pion and kaon decay constants for QCD lattice ensembles of HPQCD, CLS and ETMC. The dynamical vector mesons lead to significant impact on the evaluation of Gasser and Leutwyler’s LECs.