Enhanced production of multi-strange hadrons in high-multiplicity proton–proton collisions
Abstract
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.Citation
ALICE Collaboration (2017) 'Enhanced production of multi-strange hadrons in high-multiplicity proton–proton collisions', Nature Physics, 13, 535–539Publisher
Springer NatureJournal
Nature PhysicsDOI
10.1038/nphys4111Additional Links
http://www.nature.com/nphys/journal/v13/n6/full/nphys4111.htmlType
ArticleLanguage
enISSN
17452473EISSN
17452481ae974a485f413a2113503eed53cd6c53
10.1038/nphys4111