Enhanced production of multi-strange hadrons in high-multiplicity proton–proton collisions

Adam, J, Adamová, D, Aggarwal, MM, Rinella, GA, Agnello, M, Agrawal, N, Ahammed, Z, Ahmad, S, Ahn, SU, Aiola, S
et al (show 993 more authors) (2017) Enhanced production of multi-strange hadrons in high-multiplicity proton–proton collisions. Nature Physics, 13 (6). pp. 535-539.

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At sufficiently high temperature and energy density, nuclear matter undergoes a transition to a phase in which quarks and gluons are not confined: the quark–gluon plasma (QGP)1. Such an exotic state of strongly interacting quantum chromodynamics matter is produced in the laboratory in heavy nuclei high-energy collisions, where an enhanced production of strange hadrons is observed2,3,4,5,6. Strangeness enhancement, originally proposed as a signature of QGP formation in nuclear collisions7, is more pronounced for multi-strange baryons. Several effects typical of heavy-ion phenomenology have been observed in high-multiplicity proton–proton (pp) collisions8,9, but the enhanced production of multi-strange particles has not been reported so far. Here we present the first observation of strangeness enhancement in high-multiplicity proton–proton collisions. We find that the integrated yields of strange and multi-strange particles, relative to pions, increases significantly with the event charged-particle multiplicity. The measurements are in remarkable agreement with the p–Pb collision results10,11, indicating that the phenomenon is related to the final system created in the collision. In high-multiplicity events strangeness production reaches values similar to those observed in Pb–Pb collisions, where a QGP is formed.

Item Type: Article
Uncontrolled Keywords: Experimental nuclear physics, Experimental particle physics
Depositing User: Symplectic Admin
Date Deposited: 21 Jun 2017 13:00
Last Modified: 19 Jan 2023 07:02
DOI: 10.1038/nphys4111
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3008087