2006/03/31 by Hendrik van Hees, Ralf Rapp · 9 citations
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph
paper · pdf · doi:10.1103/physrevlett.97.102301
published as Phys.Rev.Lett. 97 (2006) 102301 · 4 pages, 4 figures, v2: slightly improved estimate of four-pion contributions; accepted for publication in Phys. Rev. Lett
arxiv created 2006/08/28 · openalex publication_date 2006/09/08 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Employing thermal dilepton rates based on a medium-modified electromagnetic correlation function we show that recent dimuon spectra of the NA60 Collaboration in central In-In collisions at the CERN-SPS can be understood in terms of radiation from a hot and dense hadronic medium. Earlier calculated in-medium rho-meson spectral functions provide an accurate description of the data up to dimuon invariant masses of about M approximately or equal to 0.9 GeV, with good sensitivity to the predicted rho-meson line shape, identifying baryon-induced modifications as the prevalent ones. A reliable evaluation of the contribution enables the study of further medium effects: at masses M>0.9 GeV, 4-pion type annihilation accounts for the experimentally observed excess (possibly augmented by effects of "chiral mixing"), while predictions for thermal emission from in-medium omega and phi mesons may be tested in the future.