ϕ meson production in p+Al, p+Au, d+Au, and He3+Au collisions at sNN=200GeV

Le résumé fourni par la source

Small nuclear collisions are mainly sensitive to cold-nuclear-matter effects; however, the collective behavior observed in these collisions shows a hint of hot-nuclear-matter effects. The identified-particle spectra, especially the $\ensuremath{\phi}$ mesons which contain strange and antistrange quarks and have a relatively small hadronic-interaction cross section, are a good tool to study these effects. The PHENIX experiment has measured $\ensuremath{\phi}$ mesons in a specific set of small collision systems $p+\mathrm{Al}$, $p+\mathrm{Au}$, and $^{3}\mathrm{He}+\mathrm{Au}$, as well as $d+\mathrm{Au}$ [Adare et al., Phys. Rev. C 83, 024909 (2011)], at $\sqrt{{s}_{{}_{NN}}}=200$ GeV. The transverse-momentum spectra and nuclear-modification factors are presented and compared to theoretical-model predictions. The comparisons with different calculations suggest that quark-gluon plasma may be formed in these small collision systems at $\sqrt{{s}_{{}_{NN}}}=200$ GeV. However, the volume and the lifetime of the produced medium may be insufficient for observing strangeness-enhancement and jet-quenching effects. The comparison with calculations suggests that the main production mechanisms of $\ensuremath{\phi}$ mesons at midrapidity may be different in $p+\mathrm{Al}$ versus $p/d/^{3}\mathrm{He}+\mathrm{Au}$ collisions at $\sqrt{{s}_{{}_{NN}}}=200$ GeV. While thermal quark recombination seems to dominate in $p/d/^{3}\mathrm{He}+\mathrm{Au}$ collisions, fragmentation seems to be the main production mechanism in $p+\mathrm{Al}$ collisions.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.