Experimental approaches for determining in-medium properties of hadrons from photo-nuclear reactions
arXiv:1111.6004 · doi:10.1016/j.ppnp.2012.01.023
Abstract
Properties of hadrons and their modification within strongly interacting matter provide a link between experimental observables and Quantum Chromodynamics (QCD) in the non-perturbative sector. The sensitivity of various observables to in-medium modifications of mesons is discussed. The transparency ratio, comparing the meson yield per nucleon within a nucleus relative to that on a free nucleon, is related to the in-medium width of the meson. While the transparency ratio can be determined for any meson lifetime the meson line shape only contains information on in-medium properties if the meson is so short-lived that it decays in the medium after production in a nuclear reaction. Light vector mesons are thus particularly suited for these investigations. The momentum distribution of mesons produced in a photo-nuclear reaction as well as the excitation function also show some sensitivity to different in-medium modification scenarios. As an example, high statistics data taken at MAMI-C on the photoproduction of ω mesons are presented.
7 pages, 6 figures, talk at International School of Nuclear Physics, 33rd course: From Quarks and Gluons to Hadrons and Nuclei, Erice-Siciliy, Sept 16-24, 2011