Constituent and current quark masses at low chiral energies

¹  Physics Department, University of Arizona - Tucson, AZ 85721, USA
²  Centro de Física das Interacções Fundamentais, Instituto Superior Técnico, Universidade Técnica de Lisboa P-1049-001 Lisboa, Portugal

Received: 10 July 2007
Accepted: 11 October 2007

Abstract

Light constituent quark masses and the corresponding dynamical quark masses are determined by data, the Quark-Level Linear Model, and infrared QCD. This allows to define effective nonstrange and strange current quark masses which reproduce the experimental pion and kaon masses very accurately, by simple additivity. Moreover, the masses of the light scalar mesons σ(600) and κ(800) can be obtained straightforwardly from the constituent quark masses. In contrast, the usual nonstrange and strange current quark masses employed by Chiral Perturbation Theory do not allow a simple quantitative explanation of the pion and kaon masses.