Spontaneous CP violation in the NJL model at θ = π

✍ Scribed by Daniël Boer; Jorn K. Boomsma

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 240 KB
• Volume: 820
• Category: Article
• ISSN: 0375-9474
• DOI: 10.1016/j.nuclphysa.2009.01.062

✦ Synopsis

As is well-known, spontaneous CP-violation in the strong interaction is possible at θ = π, which is commonly referred to as Dashen's phenomenon. This phenomenon has been studied extensively using chiral Lagrangians. Here the two-flavor NJL model at θ = π is discussed. It turns out that the occurrence of spontaneous CP-violation 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. The latter dependence shows a modification of the charged pion condensed phase first discussed by Son and Stephanov.