2004/07/31 by Hendrik van Hees, Ralf Rapp
Physics and Astronomy · #High-Energy Particle Collisions Research #Nuclear physics research studies #Quantum Chromodynamics and Particle Interactions #nucl-th
paper · pdf · doi:10.1016/j.physletb.2004.10.062
published as Phys.Lett. B606 (2005) 59-66 · 7 pages, 5 figures v2: Version accepted for publication in Phys. Lett. B, replaced one figure, added and updated references
arxiv created 2004/10/25 · openalex publication_date 2004/12/09 · arxiv updated 2009/12/01 · openalex created_date 2017/03/16 · openalex updated_date 2026/07/28
Modifications of Delta(1232) and nucleon spectral functions at finite temperature and baryon density are evaluated in terms of resonant scattering off thermal pions, as well as a renormalization of the vacuum Delta-width including vertex corrections. The interactions are based on effective Lagrangians of pions and baryon resonances, with underlying parameters (coupling constants and form factors) determined by the elastic pi N scattering phase shift in the isobar channel, and by empirical decay branchings of excited resonances. Pion modifications are included via interactions in a pion gas, as well as standard Delta- and nucleon-hole excitations in nuclear matter. In hot hadronic matter, under conditions resembling thermal freezeout at the Relativistic Heavy-Ion Collider (RHIC), the Delta exhibits a significant broadening of ~65 MeV together with a slight upward peak shift of 5-10 MeV, in qualitative agreement with preliminary data from the STAR collaboration.