2005/11/30 by T. Fujihara, Takahiro Fujihara, Tomohiro Inagaki +3 · 1 citation
Physics and Astronomy · #Chiral anomaly #Chiral symmetry breaking #Explicit symmetry breaking #High-Energy Particle Collisions Research #Isospin #Particle physics theoretical and experimental studies #Pion #Quantum Chromodynamics and Particle Interactions #Quark #Regularization (linguistics) #Spontaneous symmetry breaking #Symmetry breaking #hep-ph
paper · pdf · doi:10.1143/ptp.117.139
published as Prog.Theor.Phys.117:139-160,2007 · 22 pages, 13 figures; added discussion about pion mass difference
openalex publication_date 2007/01/01 · arxiv created 2007/01/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We study QED corrections to chiral symmetry breaking in the Nambu-Jona-Lasinio (NJL) model with two flavors of quarks. In this model, the isospin symmetry is broken by the differences between the current quark masses and the electromagnetic charges of the up and down quarks. To leading order in the 1/N expansion, we calculate the effective potential of the model with one-loop QED corrections at finite temperature. Evaluating the effective potential, we study the influence of the isospin symmetry breaking on the orientation of chiral symmetry breaking. The current quark mass plays an essential role in maintaining the orientation of the chiral symmetry breaking. If the average of the up and down quark masses is small enough, we find a phase in which the pion field has non-vanishing expectation value and dynamical CP violation takes place.