2020/08/31 by SHINE Collaboration, A. Acharya, H. Adhikary +140 · 1 citation
Physics and Astronomy · #Deconfinement #Hadron #High-Energy Particle Collisions Research #Large Hadron Collider #Multiplicity (mathematics) #Particle physics theoretical and experimental studies #Pion #Quantum Chromodynamics and Particle Interactions #Rapidity #Spectral line #Super Proton Synchrotron #Transverse mass #hep-ex #nucl-ex
paper · pdf · doi:10.1140/epjc/s10052-020-08514-6
openalex created_date 2020/08/21 · openalex publication_date 2020/10/01 · arxiv created 2021/01/20 · arxiv updated 2021/01/21 · openalex updated_date 2026/08/05
Abstract The NA61/SHINE collaboration studies at the CERN Super Proton Synchrotron (SPS) the onset of deconfinement in hadronic matter by the measurement of particle production in collisions of nuclei with various sizes at a set of energies covering the SPS energy range. This paper presents results on inclusive double-differential spectra and mean multiplicities of π - <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mi>π</mml:mi><mml:mo>-</mml:mo></mml:msup></mml:math> mesons produced in the 5% most central 7 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow/><mml:mn>7</mml:mn></mml:msup></mml:math> Be + 9 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow/><mml:mn>9</mml:mn></mml:msup></mml:math> Be collisions at beam momenta of 19 A , 30 A , 40 A , 75 A and 150 A GeV / c <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>A</mml:mi><mml:mspace/><mml:mspace/><mml:mtext>GeV</mml:mtext><mml:mspace/><mml:mspace/><mml:mo>/</mml:mo><mml:mspace/><mml:mi>c</mml:mi></mml:mrow></mml:math> obtained by the so-called h- <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mi>h</mml:mi><mml:mo>-</mml:mo></mml:msup></mml:math> method which does not require any particle identification. The shape of the transverse mass spectra differs from the shapes measured in central Pb + Pb collisions and inelastic p+p interactions. The normalized width of the rapidity distribution decreases with increasing collision energy and is in between the results for inelastic nucleon–nucleon and central Pb + Pb collisions. The mean multiplicity of pions per wounded nucleon in central 7 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow/><mml:mn>7</mml:mn></mml:msup></mml:math> Be + 9 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow/><mml:mn>9</mml:mn></mml:msup></mml:math> Be collisions is close to that in central Pb + Pb collisions up to 75 A GeV / c <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>A</mml:mi><mml:mspace/><mml:mspace/><mml:mtext>GeV</mml:mtext><mml:mspace/><mml:mspace/><mml:mo>/</mml:mo><mml:mspace/><mml:mi>c</mml:mi></mml:mrow></mml:math> . However, at the top SPS energy the result lies between those for nucleon–nucleon and Pb + Pb interactions. The results are discussed in the context of predictions for the onset of deconfinement at the CERN SPS collision energies.