At suffciently 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). 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 observed. Strangeness enhancement, originally proposed as a signature of QGP formation in nuclear collisions, is more pronounced for multi-strange baryons. Several e ects typical of heavy-ion phenomenology have been observed in high-multiplicity proton–proton (pp) collisions, 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 mea- surements are in remarkable agreement with the p–Pb collision results, 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.
Titolo: | Enhanced production of multi-strange hadrons in high-multiplicity proton–proton collisions | |
Autori: | ||
Data di pubblicazione: | 2017 | |
Stato di pubblicazione: | Pubblicato | |
Rivista: | ||
Abstract: | At suffciently 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). 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 observed. Strangeness enhancement, originally proposed as a signature of QGP formation in nuclear collisions, is more pronounced for multi-strange baryons. Several e ects typical of heavy-ion phenomenology have been observed in high-multiplicity proton–proton (pp) collisions, 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 mea- surements are in remarkable agreement with the p–Pb collision results, 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. | |
Handle: | http://hdl.handle.net/11368/2899995 | |
Digital Object Identifier (DOI): | http://dx.doi.org/10.1038/nphys4111 | |
URL: | http://www.nature.com/nphys/journal/v13/n6/full/nphys4111.html | |
Appare nelle tipologie: | 1.1 Articolo in Rivista |
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