English

Flavor-dependent U(3) Nambu Jona Lasinio coupling constant

High Energy Physics - Phenomenology 2021-06-02 v3 Nuclear Theory

Abstract

A non-perturbative one gluon exchange quark-antiquark interaction is considered to compute flavor dependent U(3) Nambu-Jona-Lasinio (NJL)-type interaction of the form Gij,Γ(ψˉλiΓψ)(ψˉλjΓψ)G_{ij, \Gamma} (\bar{\psi} \lambda_i \Gamma \psi ) ( \bar{\psi} \lambda_j \Gamma \psi) for i,j=0...8i,j=0...8 and Γ=I,iγ5\Gamma=I, i \gamma_5 from one loop polarization process with non degenerate u-d-s quark effective masses. The resulting NJL-type coupling constants in all channels are resolved in the long-wavelength limit and numerical results are presented for different choices of an effective gluon propagator. Leading deviations with respect to a flavor symmetric coupling constant are found to be of the order of (Mf2Mf1)n/(Mf2+Mf1)n(M_{f_2}^*-M_{f_1}^*)^n/(M_{f_2}^*+M_{f_1}^*)^n, for n=1,2n=1,2, where MfiM_{f_i}^* are the effective masses of quarks f1,f2=u,df_1,f_2=u, d and ss. The scalar channel coupling constants Gij,sG_{ij, s} can be considerably smaller than pseudoscalar ones. The effect of the flavor-dependence of coupling constants for the masses of pions and kaons may be nearly of the same order of magnitude as the effect of the u,d and s quark mass non-degeneracy. The effect of these coupling constants is also verified for some of the light scalar mesons masses, usually described by quark-antiquark states, and for some observables of the pseudoscalar mesons.

Keywords

Cite

@article{arxiv.2008.00346,
  title  = {Flavor-dependent U(3) Nambu Jona Lasinio coupling constant},
  author = {Fabio L. Braghin},
  journal= {arXiv preprint arXiv:2008.00346},
  year   = {2021}
}

Comments

18 pages, revised, improved and extended version, accepted for publication

R2 v1 2026-06-23T17:34:40.788Z