Thermal and Nonthermal Pion Enhancements with Chiral Symmetry Restoration
نویسندگان
چکیده
The pion production by sigma decay and its relation with chiral symmetry restoration in a hot and dense matter are investigated in the framework of the Nambu-Jona-Lasinio model. The decay rate for the process σ → 2π to the lowest order in a 1/Nc expansion is calculated as a function of temperature T and chemical potential μ. The thermal and nonthermal enhancements of pions generated by the decay before and after the freeze-out present only in the crossover region of the chiral symmetry transition. The strongest nonthermal enhancement is located in the vicinity of the endpoint of the first-order transition. PACS : 05.70.Jk, 11.30.Rd, 14.40.− n, 25.75.− q
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