Density Dependence Of Bag Constant Research Articles

Density dependence of nucleon bag constant, radius and mass in an effective field theory model of QCD

With the global color symmetry model (GCM) being extended to finite chemical potential, the density dependence of the bag constant, the total energy and the radius of a nucleon, as well as the quark condensate in nuclear matter are investigated. A maximal nuclear matter density for the existence of the bag with three quarks confined within is obtained. The calculated results indicate that, before the maximal density is reached, the bag constant, the total energy of a nucleon and the quark condensate decrease gradually, and the radius of a nucleon increases, with the increasing of the nuclear matter density. Nevertheless no sudden change emerges. As the maximal nuclear matter density is reached, a phase transition from nucleons to quarks takes place and the chiral symmetry is restored.

Density dependence of the MIT bag constant in a quark-meson coupling model

The density dependence of the MIT bag constant in nuclear matter has been determined self-consistently using some physical observables as input in a quark-meson coupling model. More precisely, for this calculation, a saturation curve of nuclear matter has been built in such a manner the empirical saturation point and compressibility are reproduced, and the real part of the Schrödinger-equivalent nucleon-nucleus optical potential at saturation density has been constrained to a realistic value. In addition, it has been required that the density dependence of the bag constant lead to a very small increase of the bag radius in nuclei in accordance to the electron-nucleus scattering data.