Volume 80, Number 5, December 2007
Article Number 51001
Number of page(s) 5
Section The Physics of Elementary Particles and Fields
Published online 06 November 2007
EPL, 80 (2007) 51001
DOI: 10.1209/0295-5075/80/51001

Constituent and current quark masses at low chiral energies

M. D. Scadron1, 2, F. Kleefeld2 and G. Rupp2

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 in final form 11 October 2007; published December 2007
published online 6 November 2007

Light constituent quark masses and the corresponding dynamical quark masses are determined by data, the Quark-Level Linear $\sigma $ 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 $\sigma $(600) and $\kappa$(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.

14.65.Bt - Light quarks.
14.40.Aq - $\pi$, K, and $\eta$ mesons.
11.30.Rd - Chiral symmetries.

© Europhysics Letters Association 2007