2008/06/30 by Daniël Boer, Daniel Boer, Jorn K. Boomsma · 3 citations
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph
paper · pdf · doi:10.1103/physrevd.78.054027
published as Phys.Rev.D78:054027,2008 · 15 pages, 11 eps figures; matches version published in Phys. Rev. D, reference added, corrected Eq. 16, modified discussion Ref. 9
openalex publication_date 2008/09/25 · arxiv created 2008/09/26 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01
Spontaneous CP violation in the strong interaction is analyzed at \ensuremathθ=\ensuremathπ within the framework of the two-flavor Nambu-Jona-Lasinio model. It is found that the occurrence of spontaneous CP violation at \ensuremathθ=\ensuremathπ depends on the strength of the 't Hooft determinant interaction, which describes the effect of instanton interactions. The dependence of the phase structure, and, in particular, of the CP-violating phase, on the quark masses, temperature, baryon and isospin chemical potential is examined in detail. When available a comparison to earlier results from chiral perturbation theory is made. From our results we conclude that spontaneous CP violation in the strong interaction is an inherently low-energy phenomenon. In all cases we find agreement with the Vafa-Witten theorem, also at nonzero density and temperature. Meson masses and mixing in the CP-violating phase display some unusual features as a function of instanton interaction strength. A modification of the condition for charged pion condensation at nonzero isospin chemical potential and a novel phase of charged a0 mesons are discussed.