Nuclear-matter modification of decay widths in the $\varphi \to e^{+}{e}^{-}$ and $\varphi \to K^{+}{K}^{-}$ channels

F. Sakuma, J. Chiba, H. En'yo +23

The invariant mass spectra of $\varphi \to K^{+}{K}^{-}$ are measured in 12 GeV $p+A$ reactions in order to search for the in-medium modification of $\varphi$ mesons. The observed $K^{+}{K}^{-}$ sp…