The width of the omega meson in the nuclear medium

Abstract

We evaluate the width of the $\ddot{I}‰$ meson in nuclear matter. We consider the free decay mode of the $\ddot{I}‰$ into three pions, which is dominated by $\ddot{I}\ddot{I}€$ decay, and replace the $\ddot{I}$ and $\ddot{I}€$ propagators by their medium modified ones. We also take into account the quasielastic and inelastic processes induced by a vector-baryon interaction dominated by vector meson exchange, as well as the contributions coming from the $\ddot{I}‰\to K\bar{K}$ mechanism with medium modified $K$, $\bar{K}$ propagators. We obtain a substantial increase of the $\ddot{I}‰$ width in the medium, reaching a value of $129\pm 10$ MeV at normal nuclear matter density for an $\ddot{I}‰$ at rest, which comes mainly from $\ddot{I}‰N\to \ddot{I}€\ddot{I}€N,\ddot{I}‰NN\to \ddot{I}€NN$ processes associated to the dominant $\ddot{I}‰\to \ddot{I}\ddot{I}€$ decay mode. The value of the width increases moderately with momentum, reaching values of around 200 MeV at 600 MeV/c.

25 pages, 14 figures, revised version to appear published in Eur. Phys. J. A