rho-Meson properties in medium

Properties of rho-meson in symmetric nuclear matter are investigated in a light-front constituent quark model (LFCQM), using the in-medium inputs calculated by the quark-meson coupling (QMC) model. The LFCQM used in this study was already applied for the studies of the electromagnetic properties of rho-meson in vacuum, namely, the charge G(0), magnetic G1, and quadrupole G(2) form factors, electromagnetic charge radius, and electromagnetic decay constant. Using the two different density dependence of the regulator mass in medium, we predict that the charge radius, and quadrupole moment are enhanced as increasing the nuclear matter density, while the magnetic moment is slightly quenched. Furthermore, we predict the value Q(zero)(2), which crosses zero of the charge form factor, G(0)(Q(zero)(2)) = 0 (Q(2)= -q 2 > 0 with q being the four-momentum transfer), decreases as increasing the nuclear matter density by the two different density dependence of the regulator mass. On the other hand, for the electromagnetic decay constant of the rho-meson, the two different density dependence of the regulator mass predict the opposite density dependence. Namely, as increasing the nuclear matter density, the naive treatment with the density independent regulator mass as in the vacuum, predicts the increase of the decay constant, while the other that assumes the same density dependence of the regulator mass as that of the in-medium constituent quark mass, predicts the decrease of the decay constant. Thus, although the other physical quantities are predicted to have similar density dependence by the two different density dependence of the regulator mass applied, the density dependence of the rho-meson electromagnetic decay constant is predicted to have opposite density dependence, and the facts suggest that the in-medium rho-meson decay constant needs to be investigated further in the future. (C) 2018 The Authors. Published by Elsevier B.V. (AU)