Matter effects on $\eta$ and ${\eta }^{\prime }$ mesons

Abstract

We show how the nuclear medium affects the masses of the $\eta$ and ${\eta }^{\prime }$ mesons. The change should be easily detectable for dense matter and/or strong $\eta ({\eta }^{\prime })N\bar{N}$ coupling. We also find that the $\eta -{\eta }^{\prime }$ mixing angle is less in magnitude in the nuclear matter than in vacuum.

Comments: LaTeX file + 5 figures, requires epsf.sty