Momentum dependence of hadronic production of the ϕ-meson and its width in nuclear matter

Abstract

Information on the properties of the φ meson in the nuclear environment has been derived from its production in proton collisions with C, Cu, Al, and Au nuclear targets. The experiment was carried out with 2.83 GeV protons at the Cooler Synchrotron COSY, with the φ being detected via its K + K − decay using M. Hartmann et al. the ANKE magnetic spectrometer. The measured dependence of the production cross section on the nuclear mass number has been compared with calculations within three different nuclear models. These suggest a significant broadening of the width of the φ in medium relative to its vacuum value. The ANKE results obtained in the momentum range 0.6 < p φ < 1.6 GeV/c are compared with data from photoproduction experiments at slightly higher momenta.