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تسجيل مستخدم جديدSystem size and energy dependence of near-side di-hadron correlations
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Two-particle azimuthal ($Deltaphi$) and pseudorapidity ($Deltaeta$) correlations using a trigger particle with large transverse momentum ($p_T$) in $d$+Au, Cu+Cu and Au+Au collisions at $sqrt{s_{{NN}}}$ =xspace 62.4 GeV and 200~GeV from the STAR experiment at RHIC are presented. The s correlation is separated into a jet-like component, narrow in both $Deltaphi$ and $Deltaeta$, and the ridge, narrow in $Deltaphi$ but broad in $Deltaeta$. Both components are studied as a function of collision centrality, and the jet-like correlation is studied as a function of the trigger and associated $p_T$. The behavior of the jet-like component is remarkably consistent for different collision systems, suggesting it is produced by fragmentation. The width of the jet-like correlation is found to increase with the system size. The ridge, previously observed in Au+Au collisions at $sqrt{s_{{NN}}}$ = 200 GeV, is also found in Cu+Cu collisions and in collisions at $sqrt{s_{{NN}}}$ =xspace 62.4 GeV, but is found to be substantially smaller at $sqrt{s_{{NN}}}$ =xspace 62.4 GeV than at $sqrt{s_{{NN}}}$ = 200 GeV for the same average number of participants ($ langle N_{mathrm{part}}rangle$). Measurements of the ridge are compared to models.
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