Antiproton over proton and K- over K+ multiplicity ratios at high z in DIS

0533930 - ÚPT 2021 RIV NL eng J - Journal Article
Alexeev, G. D. - Alexeev, M. G. - Amoroso, A. - Srnka, Aleš … Total 200 authors
Antiproton over proton and K- over K+ multiplicity ratios at high z in DIS.
Physics Letters. B. Roč. 807, AUG (2020), č. článku 135600. ISSN 0370-2693. E-ISSN 1873-2445
Institutional support: RVO:68081731
Keywords : quantum chromodynamics * pQCD * deep-inelastic scattering * hadron multiplicities * compass
OECD category: Particles and field physics
Impact factor: 4.771, year: 2020
Method of publishing: Open access
https://www.sciencedirect.com/science/article/pii/S0370269320304044

The antiparticle-over-particle multiplicity ratio is measured in deep-inelastic scattering for negatively and positively charged kaons and, for the first time, for antiprotons and protons. The data were obtained by the COMPASS Collaboration using a 160 GeV muon beam impinging on an isoscalar (LiD)-Li-6 target. The regime of deep-inelastic scattering is ensured by requiring Q(2) > 1 (GeV/c)(2) for the photon virtuality and W > 5 GeV/c(2) for the invariant mass of the produced hadronic system. Bjorken-x is restricted to the range 0.01 to 0.40. Protons and antiprotons are identified in the momentum range from 20 GeV/c to 60 GeV/c and required to carry a large fraction of the virtual-photon energy, z > 0.5. In the whole studied z-region, the P over p multiplicity ratio is found to be below the lower limit expected from calculations based on leading-order perturbative Quantum Chromodynamics (pQCD). Kaons were previously analysed in the momentum range 12 GeV/c to 40 GeV/c. In the present analysis this range is extended up to 55 GeV/c, whereby events with larger virtual-photon energies are included in the analysis and the observed K- over K+ ratio becomes closer to the expectation of next-to-leading order pQCD. The results of both analyses strengthen our earlier conclusion that at COMPASS energies the phase space available for single-hadron production in deep-inelastic scattering should be taken into account in the standard pQCD formalism. (C) 2020 Published by Elsevier B.V.
Permanent Link: http://hdl.handle.net/11104/0312158