https://doi.org/10.1140/epjc/s10052-020-08514-6
Regular Article – Experimental Physics
Measurements of 
production in 
Be + 
Be collisions at beam momenta from 19A to 150
in the NA61/SHINE experiment at the CERN SPS
NA61/SHINE Collaboration
1
National Nuclear Research Center, Baku, Azerbaijan
2
Faculty of Physics, University of Sofia, Sofia, Bulgaria
3
Ruđer Bošković Institute, Zagreb, Croatia
4
LPNHE, University of Paris VI and VII, Paris, France
5
Karlsruhe Institute of Technology, Karlsruhe, Germany
6
University of Frankfurt, Frankfurt, Germany
7
Wigner Research Centre for Physics of the Hungarian Academy of Sciences, Budapest, Hungary
8
University of Bergen, Bergen, Norway
9
Jan Kochanowski University in Kielce, Kielce, Poland
10
Institute of Nuclear Physics, Polish Academy of Sciences, Kraców, Poland
11
National Centre for Nuclear Research, Warsaw, Poland
12
Jagiellonian University, Kraców, Poland
13
AGH, University of Science and Technology, Kraców, Poland
14
University of Silesia, Katowice, Poland
15
University of Warsaw, Warsaw, Poland
16
University of Wrocław, Wrocław, Poland
17
Warsaw University of Technology, Warsaw, Poland
18
Institute for Nuclear Research, Moscow, Russia
19
Joint Institute for Nuclear Research, Dubna, Russia
20
National Research Nuclear University (Moscow Engineering Physics Institute), Moscow, Russia
21
St. Petersburg State University, St. Petersburg, Russia
22
University of Belgrade, Belgrade, Serbia
23
University of Geneva, Geneva, Switzerland
24
Fermilab, Batavia, USA
25
University of Colorado, Boulder, USA
26
University of Pittsburgh, Pittsburgh, USA
Received:
14
August
2020
Accepted:
2
October
2020
Published online:
19
October
2020
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 
mesons produced in the 5% most centralBe + Be collisions at beam momenta of 19A, 30A, 40A, 75A and 150 obtained by the so-called 
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 centralBe + Be collisions is close to that in central Pb + Pb collisions up to 75. 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.
© The Author(s) 2020
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Funded by SCOAP3.
