The sigma meson in a nuclear medium through two pion photoproduction

摘要

We present theoretical results for (gamma, pi(0)pi(0)) production on nucleons and nuclei in the kinematical region where the scalar isoscalar pipi amplitude is influenced by the a pole. The final-state interaction of the pions modified by the nuclear medium produces a spectacular shift of strength of the two pion invariant mass distribution induced by the moving of the sigma pole to lower masses and widths as the nuclear density increases. (C) 2002 Elsevier Science B.V. All rights reserved. References: 52