From: Flemming Videbaek (videbaek@sgs1.hirg.bnl.gov)
Date: Tue Apr 22 2003 - 09:53:22 EDT
FYI ------------------------------------------------------ Flemming Videbaek Physics Department Brookhaven National Laboratory tlf: 631-344-4106 fax 631-344-1334 e-mail: videbaek@bnl.gov ----- Original Message ----- From: "William A. Zajc" <zajc@nevis.columbia.edu> To: "'Thomas Kirk'" <tkirk@bnl.gov>; "'Wit Busza '" <busza@mit.edu>; "'Hallman, Timothy J'" <hallman@bnl.gov>; "'Videbaek, Flemming'" <videbaek@bnl.gov> Sent: Monday, April 21, 2003 2:56 PM Subject: New PHENIX papers on pi0 production in Au-Au and p-p collisions at 200 GeV | Dear Tom, Wit, Tim and Flemming: | | I am pleased to announce that our results on pi0 production from 200 GeV | Au-Au and p-p collisions will be submitted to Physical Review Letters in | one week. We have prepared two manuscripts, and will request that they | appear as companion articles in PRL. The titles and abstracts are | included below. The results are essentially the same as our preliminary | data presented at QM02 last July. | | Best regards, | | Bill | | ------------------------------------------------------------------------ | ---------------------------- | | Suppressed $\pi^0$ Production at Large Transverse Momentum | in Central Au+Au Collisions at $\sqrt{s_{_{NN}}}$~=~200~GeV | | | \begin{abstract} | Transverse momentum spectra of neutral pions in the range 1 $< p_T <$ | 10~GeV$/c$ | have been measured at mid-rapidity by the PHENIX experiment at RHIC in | Au+Au collisions at $\sqrt{s_{_{NN}}}$ = 200~GeV. The $\pi^0$ | multiplicity in central reactions is significantly below the yields | measured at the | same $\sqrt{s_{_{NN}}}$ in peripheral Au+Au and $p+p$ reactions scaled | by the | number of nucleon-nucleon collisions. For the most central bin, the | suppression | factor is $\sim$2.5 at $p_T$ = 2 GeV$/c$ and increases to $\sim$4-5 at | $p_T\approx$ 4 GeV$/c$. | At larger $p_T$, the suppression remains constant within errors. The | deficit is | already apparent in semi-peripheral reactions and increases smoothly | with centrality. | \end{abstract} | ------------------------------------------------------------------------ | ---------------------------- | | Mid-Rapidity Neutral Pion Production in Proton-Proton Collisions | at $\mathbf{\sqrt{s}}$=200~GeV | | \begin{abstract} | The invariant differential cross section for inclusive neutral pion | production in | $p\!+\!p$ collisions at $\sqrt{s}$~=~200~GeV has been measured at | mid-rapidity | ($|\eta|\!<\!0.35$) over the range $ 1\!<\!p_T\! \alt \!14$~GeV/$c$ | by the PHENIX experiment at RHIC. | Predictions of next-to-leading order perturbative QCD calculations | are consistent with these measurements. The precision of our result is | sufficient | to differentiate between prevailing, gluon-to-pion fragmentation | functions. | \end{abstract} | ------------------------------------------------------------------------ | ---------------------------- |
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