Speaker
Michael Tannenbaum
(Brookhaven National Laboratory (US))
Description
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 |
|---|
Author
Michael Tannenbaum
(Brookhaven National Laboratory (US))
