Mesonic and nucleon fluctuation effects at finite baryon density

Abstract

Mesonic and nucleon fluctuation effects are investigated in medium. We couple the nucleon field to the $2+1$ flavor meson model and investigate the finite temperature and density behavior of the system, in particular, the axial anomaly function. Somewhat contrary to earlier expectations we find that it tends to strengthen at finite density. At lower temperatures nucleon density fluctuations can cause a relative difference in the $U_A(1)$ axial anomaly of about $20\%$. This has important consequences on the mesonic spectra, especially on the $\eta -{\eta }^{\prime }$ system, as we observe no drop in the ${\eta }^{\prime }$ mass as a function of the baryochemical potential, irrespective of the temperature. Based on the details of chiral symmetry restoration, it is argued that there has to be a competition between underlying QCD effects of the anomaly and fluctuations of the low energy hadronic degrees of freedom, and the fate of the $U_A(1)$ coefficient should be decided by taking into account both effects simultaneously.

9 pages, 4 figures, matches published version

References in corpus (6)

• Microscopic Origin of \boldmath{$U_A(1)$} Symmetry Violation in the High Temperature Phase of QCD
• η- and η'-mesic nuclei and U_A(1) anomaly at finite density
• Baryon number fluctuations at finite temperature and density
• In-medium Pion and Partial Restoration of Chiral Symmetry
• Pseudoscalar neutral mesons in hot and dense matter
• Functional renormalization group studies of nuclear and neutron matter

Cited by in corpus (13)

• The QCD phase structure at finite temperature and density
• QCD at finite temperature and density within the fRG approach: An overview
• Mass sensitivity of the three-flavor chiral phase transition
• Chiral and $U(1{)}_A$ restoration for the scalar/pseudoscalar meson nonets
• Probing the hadron mass spectrum in dense two-color QCD with the linear sigma model
• Comprehensive study of mass modifications of light mesons in nuclear matter in the three-flavor extended Linear Sigma Model
• Axial anomaly and hadronic properties in a nuclear medium
• Fate of the topological susceptibility in two-color dense QCD
• New Insight about the Effective Restoration of U_A(1) Symmetry
• Structure of eta' mesonic nuclei in a relativistic mean field theory
• Spectral function of the ${\eta }^{\prime }$ meson in nuclear medium based on phenomenological models
• Chiral effective model of cold and dense two-color QCD: The linear sigma model approach
• QCD chiral condensate and pseudoscalar-meson properties in the nuclear medium at finite temperature