Dense baryonic matter in the hidden local symmetry approach

Abstract

The dense baryonic matter and hadron properties in medium were simulated by using a Skyrme model including the ground state vector mesons introduced from the hidden local symmetry approach up to the next to leading order. We found that both the $ρ$ and $ω$ mesons affect the baryonic matter and medium modified hadron properties dramatically. The most remarkable observation is that, the pion decay constant and the nucleon mass have the similar density dependence which agrees with the large $N_c$ argument. Explicitly, they drop with increasing density in the Skyrmion phase and stop decreasing at $n_{1/2}^{}$ at which the skyrmions in medium fractionize into half-skyrmions and remains nearly constants in the half-skyrmion phase. This density dependence in the half-skyrmion phase indicates that, although $\langle \bar{q}q\rangle \neq 0$ on average in this phase, chiral symmetry is not restored since hadrons are still massive and there exist pions. In addition, the nearly constant nucleon mass means that it could has a non-vanishing component up to the chiral transition, which might shed light on the origin of the nucleon mass.