Weak Decay of $\Lambda$ in Nuclei : Quarks vs Mesons

Abstract

Decays of $\Lambda$ in nuclei, nonmesonic mode, are studied by using the $\Lambda N\to NN$ weak transition potential derived from the meson exchange mechanism and the direct quark mechanism. The decay rates are calculated both for the $\Lambda$ in symmetric nuclear matter and light hypernuclei. We consider the exchange of six mesons ($\pi ,K,\eta ,\rho ,\omega ,K^{\ast }$). The form factor in the meson exchange mechanism and short range correlation are carefully studied.

Comments: 22 pages, 14 figures