2006/04/30 by Wei Liu, W. Liu, Ralf Rapp +1
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #nucl-th
paper · pdf · doi:10.1016/j.nuclphysa.2007.08.014
published as Nucl.Phys.A796:101-121,2007 · version to appear in Nucl. Phys. A
arxiv created 2007/09/04 · openalex publication_date 2007/09/17 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Within an effective hadronic model including electromagnetic interactions via a U\rm em(1) gauge, we reinvestigate photon Bremsstrahlung from a hot hadronic gas as expected to be formed in relativistic heavy-ion collisions at SPS energies. We calculate photon emission from the reactions ππ→ππγ and πK →πKγ by an explicit (numerical) evaluation of the multi-dimensional phase space integral. This, in particular, allows to avoid the commonly employed soft photon approximation (SPA), as well as to incorporate final-state thermal enhancement factors. % during the hadronic stage of the fireball. Both improvements are shown to result in an appreciable increase of the photon production rate over previous hadronic calculations. Upon convolution over a thermal fireball we find an improvement in the description of recent low transverse-momentum WA98 data at SPS. The influence of both Landau-Pomeranchuk-Migdal and in-medium effects on "σ" and ρ-meson exchanges are briefly discussed.