Strange mass dependence of the tricritical point in the U(3) L×U(3)R chiral sigma model

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Abstract

We study the strange quark mass dependence of the tricritical point of the U(3)L×U(3)R linear sigma model in the chiral limit. Assuming that the tricritical point is at a large strange mass value, the strange sector as well as the η-a0 sector decouples from the light degrees of freedom which determines the thermodynamics. By tracing this decoupling we arrive from the original U(3)L×U(3)R symmetric model, going through the U(2)L×U(2)R symmetric one, at the SU(2)L×SU(2)R linear sigma model. One-loop level beta functions for the running of the parameters in each of these models and tree-level matching of the coupling of these models performed at intermediate scales are used to determine the influence of the heavy sector on the parameters of the SU(2)L×SU(2)R linear sigma model. By investigating the thermodynamics of this latter model we identified the tricritical surface of the U(3)L×U(3) R linear sigma model in the chiral limit. To apply the results for QCD we used different scenarios for the ms and μq dependence of the effective model parameters, and then the μqTCP(m s) function can be determined. Depending on the details, a curve bending upwards or downwards near μq=0 can be obtained, while with explicit chemical potential dependence of the parameters the direction of the curve can change with ms, too.

Original languageEnglish
Article number125038
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Volume82
Issue number12
DOIs
Publication statusPublished - Dec 1 2010

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ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)

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