Transverse Energy ($E_T$) distributions at mid-rapidity in $p$$+$$p$, $d$$+$Au and Au$+$Au collisions at $\sqrt{s_{{}_{NN}}}$=200 GeV and implications for particle production models

Abstract

Measurements of the midrapidity transverse energy distribution $d{\mathrm{E}}_T/d\eta$ are presented for $p$$+$$p$, $d$$+$Au, and Au$+$Au Collisions at $\sqrt{s_{{}_{NN}}}$=62.4--200 GeV. The ${\mathrm{E}}_T$ distributions are compared with the number of participants, $N_{\mathrm{part}}$, the number of constituent-quark participants, $N_{qp}$, and the number of color-strings (Additive Quark Model-AQM) calculated from a Glauber model. For Au$+$Au, $⟨d{\mathrm{E}}_T/d\eta /(0.5N_{\mathrm{part}})⟩$ increases with $N_{\mathrm{part}}$, while $⟨d{\mathrm{E}}_T/d\eta /N_{qp}⟩$ is approximately constant vs. centrality for $\sqrt{s_{{}_{NN}}}\ge 62.4$ GeV. This indicates that the two component ansatz, $d{\mathrm{E}}_T^{\mathrm{AA}}/d\eta =(d{\mathrm{E}}_T^{\mathrm{pp}}/d\eta )[(1-x)N_{\mathrm{part}}/2+x{N}_{\mathrm{coll}}]$, which has been used to represent ${\mathrm{E}}_T$ distributions, is simply a proxy for $N_{qp}$, and that the $N_{\mathrm{coll}}$ term does not represent a hard-scattering component in ${\mathrm{E}}_T$ distributions. The $d{\mathrm{E}}_T/d\eta$ distributions of $d$$+$Au, and Au$+$Au are calculated from the measured $p$$+$$p$ ${\mathrm{E}}_T$ distribution using two models (AQM and $N_{qp}$) that both reproduce the Au$+$Au data. For the asymmetric $d$$+$Au system, the $N_{qp}$ model reproduces the data while the AQM does not.

4 pages, 4 figures, Proceedings of the "Quark Matter 2014 Conference", XXIV International Conference on Ultrarelativistic Nucleus-Nucleus Collisions, Darmstadt, May 19-24 2014. In press Nuclear Physics A

References in corpus (2)

• Centrality dependence of the charged-particle multiplicity density at mid-rapidity in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV
• Transverse-energy distributions at midrapidity in $p$$+$$p$, $d$$+$Au, and Au$+$Au collisions at $\sqrt{s_{{}_{NN}}}=62.4$--200~GeV and implications for particle-production models

Cited by in corpus (1)

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