# Measurement of the relative yields of $\psi(2S)$ to $\psi(1S)$ mesons produced at forward and backward rapidity in $p$+$p$, $p$+Al, p$+$Au, and $^{3}$He$+$Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV

Abstract : The PHENIX Collaboration has measured the ratio of the yields of $\psi(2S)$ to $\psi(1S)$ mesons produced in $p$+$p$, $p$+Al, p$+$Au, and $^{3}$He$+$Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV over the forward and backward rapidity intervals $1.2<|y|<2.2$. We find that the ratio in $p$+$p$ collisions is consistent with measurements at other collision energies. In collisions with nuclei, we find that in the forward ($p$-going or $^{3}$He-going) direction, the relative yield of $\psi(2S)$ mesons to $\psi(1S)$ mesons is consistent with the value measured in \pp collisions. However, in the backward (nucleus-going) direction, the $\psi(2S)$ is preferentially suppressed by a factor of $\sim$2. This suppression is attributed in some models to breakup of the weakly-bound $\psi(2S)$ through final state interactions with comoving particles, which have a higher density in the nucleus-going direction. These breakup effects may compete with color screening in a deconfined quark-gluon plasma to produce sequential suppression of excited quarkonia states.
Type de document :
Article dans une revue
Physical Review C, American Physical Society, 2017, 95, pp.034904. 〈10.1103/PhysRevC.95.034904〉

http://hal.in2p3.fr/in2p3-01447887
Contributeur : Sophie Heurteau <>
Soumis le : vendredi 27 janvier 2017 - 12:25:50
Dernière modification le : mardi 20 novembre 2018 - 10:07:01

### Citation

A. Adare, C. Aidala, N. N. Ajitanand, Y. Akiba, M. Alfred, et al.. Measurement of the relative yields of $\psi(2S)$ to $\psi(1S)$ mesons produced at forward and backward rapidity in $p$+$p$, $p$+Al, p$+$Au, and $^{3}$He$+$Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV. Physical Review C, American Physical Society, 2017, 95, pp.034904. 〈10.1103/PhysRevC.95.034904〉. 〈in2p3-01447887〉

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