Transverse energy distributions at mid-rapidity in $p$$+$$p$, $d$$+$Au, and Au$+$Au collisions at $\sqrt{s_{NN}} = $62.4--200 GeV and implications for particle production models

May 19, 2014, 11:20 AM
europium (darmstadtium)



Contributed Talk Collective Dynamics Collective dynamics


Michael Tannenbaum (Brookhaven National Laboratory (US))


Measurements of the midrapidity transverse energy distribution $dE_T/d\eta$, are presented for $p$$+$$p$, $d$$+$Au, and Au$+$Au collisions at 62.4--200 GeV. The $E_T$ distributions are compared with the number of participants, $N_{\mathrm{part}}$, the number of binary collisions, $N_{\mathrm{coll}}$, and the number of constituent-quark participants, $N_{qp}$, calculated from a Glauber model. For Au$+$Au, $(dE_T/d\eta)/N_{\mathrm{part}}$ indicates that the two component ansatz $dE_T/d\eta ~ (1-x)N_{\mathrm{part}}/2+xN_{\mathrm{coll}}$, which has been used to explain $E_T$ distributions is simply a proxy for $N_{qp}$, and that the $N_{\mathrm{coll}}$ term does not represent a hard-scattering component in $E_T$ distributions. The $dE_T/d\eta$ distributions of Au$+$Au and $d$$+$Au are then calculated from the measured $p$$+$$p$ $E_T$ distributions using two models (additive quark model and the number-of-constituent quarks model) that both reproduce the Au$+$Au data. However, the number-of-constituent-quark-participant model agrees well with the $d$$+$Au data, while the additive quark model does not. A description of the various models and their implications will be discussed.
On behalf of collaboration: PHENIX

Primary author

Michael Tannenbaum (Brookhaven National Laboratory (US))

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