Hades Experiments: Investigation of Hadron In-medium Properties

Abstract

Abstract.Hadron modifications in nuclear matter are discussed in connection to chiral symmetry restoration and/or hadronic many body effects. Experiments with photon, proton and heavy ion beams are used to probe properties of hadrons embedded in nuclear matter at different temperatures and densities. Most of the information has been gathered for the light vector mesons ρ, ω and φ. HADES is a second generation experiment operating at GSI with the main aim to study in-medium modifications by means of dielectron production at the SIS18/Bevelac energy range. Large acceptance and excellent particle identification capabilities allows also for measurements of strangeness production. These abilities combined with the variety of beams provided by the SIS18 allow for a characterization of properties of the dense baryonic matter properties created in heavy ion collisions at these energies. A review of recent experimental results obtained by HADES is presented, with main emphasis on hadron properties in nuclear matter.

Meson vacuum phenomenology in a three-flavor linear sigma model with (axial-)vector mesons

“…Obviously, these considerations are only qualitative but could represent the starting point of interesting studies of vector mesons in the medium, which is an important aim of several experimental investigations [59]. To this end, one has to calculate the behavior of the dilaton and chiral condensates in the medium within the same theoretical framework.…”

Baryons as relativistic three-quark bound states

“…Dispersion theory makes it clear that the timelike and spacelike properties are intrinsically related, and in this respect it is curious that many quark models capable of providing a good spacelike description do not have such mechanisms implemented at all (with exceptions discussed further below). In any case, the experimental situation may change in the future with new precision data on timelike nucleon form factors expected from Novosibirsk, BESIII/Beijing and PANDA/FAIR [449], and timelike reactions are also promising tools to extract the properties of nucleon resonances [485][486][487]. …”