[Brahms-l] Fw: New PHENIX paper on neutral pion suppression in Au+Au at 200 GeV

FYI


Subject: New PHENIX paper on neutral pion suppression in Au+Au at 200 GeV


> Dear Wit, Tim, Flemming and Peter:
> 
> In one week's time PHENIX will submit to Physical Review C a paper on the
> systematics of pi0 suppression in full energy Au+Au collisions. The title
> and abstract are included below.
> 
> Best regards,
> 
> Bill
> 
> ----------------------------------------------------------------------------
> ---------------------------------
> 
> TITLE: A Detailed Study of High-pT Neutral Pion Suppression and Azimuthal
> Anisotropy in Au+Au Collisions at \sqrt{s_{NN}} = 200 GeV
> 
> ABSTRACT:
> 
> Measurements of neutral pion  production at mid-rapidity in \sqrt{s_{NN}}  =
> 200 GeV Au+Au collisions
> as a function of transverse momentum, pT , collision centrality, and angle
> with respect to reaction plane
> are presented. The data represent the final pi0 results from the PHENIX
> experiment for the first RHIC
> Au+Au run at design center-of-mass-energy. They include additional data
> obtained using the PHENIX
> Level-2 trigger with more than a factor of three increase in statistics over
> previously published results
> for pT > 6 GeV/c. We evaluate the suppression in the yield of high-pT pi0's
> relative to point-like scaling
> expectations using the nuclear modification factor R_AA. We present the pT
> dependence of R_AA for nine bins
> in collision centrality. We separately integrate R_AA over larger pT bins to
> show more precisely the centrality
> dependence of the high-pT suppression. We then evaluate the dependence of
> the high-pT suppression on
> the emission angle \Delta\phi of the pions with respect to event reaction
> plane for 7 bins in collision centrality. We show that the yields of high-pT
> pi0's vary strongly with \Delta\phi, consistent with prior measurements [1,
> 2]. We show that this variation persists in the most peripheral bin
> accessible in this analysis. For the peripheral bins we observe no
> suppression for neutral pions produced aligned with the reaction plane while
> the yield of pi0's produced perpendicular to the reaction plane is
> suppressed by a factor of > 2. We analyze the
> combined centrality and \Delta\phi dependence of the pi0 suppression in
> different pT bins using different possible
> descriptions of parton energy loss dependence on jet path-length averages to
> determine whether a single
> geometric picture can explain the observed suppression pattern.
> 
>
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