부산대학교 도서관

The Nambu--Jona-Lasino model is modified by the inclusion of a running-coupling that was obtained by a fractal approach to Quantum Chromodynamics. The coupling follows a $q$-exponential function and, in the context of high energy collisions, explains the origin of the Tsallis non-extensive statistics distributions. The parameter $q$ is completely determined in terms of the number of colours and the number of quark flavours. We study several aspects of the extended model and compare our results to the standard NJL model, where a constant coupling is used in combination with a sharp cutoff to regularize the gap equation. We show that the modified coupling regularizes the model like a smooth cutoff and reproduces the pion mass and decay constant, providing an almost exact Gell-Mann-Oakes-Renner relation at physical current quark masses.
Comment: 14 pages, 6 figures, 1 table