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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.
Charmonium is a valuable probe in heavy-ion collisions to study the properties of the quark gluon plasma, and is also an interesting probe in small collision systems to study cold nuclear matter effects, which are also present in large collision syst
Measurements of bottomonium production in heavy ion and $p$$+$$p$ collisions at the Relativistic Heavy Ion Collider (RHIC) are presented. The inclusive yield of the three $Upsilon$ states, $Upsilon(1S+2S+3S)$, was measured in the PHENIX experiment vi
The fraction of $J/psi$ mesons which come from B-meson decay, $textrm{F}_{B{rightarrow}J/psi}$, is measured for J/$psi$ rapidity mbox{$1.2<|y|<2.2$} and $p_T>0$ in $p$+$p$ and Cu+Au collisions at $sqrt{s_{_{NN}}}$=200 GeV with the PHENIX detector. Th
We report $J/psi$ spectra for transverse momenta $p_T$> 5 GeV/$c$ at mid-rapidity in p+p and Au+Au collisions at sqrt(s_{NN}) = 200 GeV.The inclusive $J/psi$ spectrum and the extracted $B$-hadron feed-down are compared to models incorporating differe
The PHENIX experiment has studied nuclear effects in $p$$+$Al and $p$$+$Au collisions at $sqrt{s_{_{NN}}}=200$ GeV on charged hadron production at forward rapidity ($1.4<eta<2.4$, $p$-going direction) and backward rapidity ($-2.2<eta<-1.2$, $A$-going