1994/12/23 by J. Barrette, R. Bellwied, P. Braun‐Munzinger +42 · 57 citations
Physics and Astronomy · #Atomic physics #Hadron #High-Energy Particle Collisions Research #Materials science #Momentum (technical analysis) #Nuclear physics #Nucleus #Particle physics theoretical and experimental studies #Physics #Pion #Proton #Quantum Chromodynamics and Particle Interactions #Range (aeronautics) #Rapidity #Resonance (particle physics) #Spectral line #Transverse plane #Yield (engineering) #nucl-ex
paper · pdf · open access · doi:10.1016/0370-2693(95)00329-j
published in Physics Letters B 351(1-3), 93-98 (Elsevier BV) · 12 pages + 4 figures (uuencoded at end-of-file)
arxiv created 1994/12/23 · openalex publication_date 1995/05/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present measurements of pion transverse momentum (pt) spectra in central Si-nucleus collisions in the rapidity range 2.0 < y < 5.0 for pt down to and including pt = 0. The data exhibit an enhanced pion yield at low pt compared to what is expected for a purely thermal spectral shape. This enhancement is used to determine the Δ resonance abundance at freeze-out. The results are consistent with a direct measurement of the Δ resonance yield by reconstruction of proton-pion pairs and imply a temperature of the system at freeze-out close to 140 MeV.