η- and η'-mesic nuclei and U_A(1) anomaly at finite density

Abstract

We discuss theoretically the possibility of observing the bound states of the ηand η'(958) mesons in nuclei. We apply the NJL model to study the ηand η' meson properties at finite density and calculate the formation cross sections of the ηand η' bound states with the Green function method for (γ,p) reaction. We also discuss the experimental feasibility at photon facilities like SPring-8. The contributions due to the ωmeson production are also included to obtain the realistic (γ,p) spectra. We conclude that we can expect to observe resonance peaks in (γ,p) spectra for the formation of meson bound states and we can deduce new information on ηand η' properties at finite density. These observations are believed to be essential to know the possible mass shift of η' and deduce new information on the effective restoration of the U_A(1) anomaly in the nuclear medium.

10 pages, 7 figures, a few references and comments are added, published in PRC

References in corpus (3)

• Pseudoscalar neutral mesons in hot and dense matter
• Analysis of U${}_A$(1) symmetry-breaking and restoration effects on the scalar-pseudoscalar spectrum
• Possible eta-mesic 3He states within the finite rank approximation

Cited by in corpus (8)

• Level crossing of particle-hole and mesonic modes in eta mesic nuclei
• Interactions of Non-Abelian Global Strings
• U_A(1) Anomaly in Hot and Dense QCD and the Critical Surface
• Non-Abelian Global Vortices
• Study of possible ωbound states in nuclei with the (γ,p) reaction
• Formation spectra of light kaonic nuclei by in-flight ($\bar{K},N$) reactions with chiral unitary amplitude
• Interference and nuclear medium effects on the eta-mesic nuclear spectrum
• Formation of Deeply Bound Kaonic Atoms in (K^-,N) Reactions