[Brahms-l] Fw: New PHENIX paper on eta production at RHIC

FYI


> -------------------------------------
> 
> Title: High transverse momentum eta meson production in p+p, d+Au and Au+Au
> collisions at sqrt{s_{NN}} = 200 GeV
> 
> Abstract:
> 
> Inclusive transverse momentum spectra of eta mesons in the range pT \approx
> 2-12 GeV/c have been measured
> at mid-rapidity (|\eta| < 0,35) by the PHENIX experiment at RHIC in p+p,
> d+Au and Au+Au collisions at sqrt{s_{NN}}
> = 200 GeV. The eta mesons are reconstructed through their eta-->
> \gamma\gamma channel for the three colliding systems as well as through the
> eta--> Pi0 pi+ pi- decay mode in p+p and d+Au collisions. The nuclear
> modification factor in d+Au collisions, R_dAu(pT \approx 1.0-1.1, suggests
> at most only modest pT broadening ("Cronin enhancement"). In central Au+Au
> reactions, the eta yields are significantly suppressed, with R_AuAu(pT )
> \approx 0.2. The ratio of eta to pi0 yields is approximately constant as a
> function of pT for the three colliding systems in agreement with the high-pT
> world average of R_eta/pi0 \approx 0.5 in hadron-hadron, hadron-nucleus, and
> nucleus-nucleus collisions for a wide range of center-of-mass energies
> (sqrt{s_{NN}} \approx 3-1800 GeV) as well as, for high scaled momentum x_p,
> in e+e- annihilations at \sqrt{s} = 91.2 GeV. These results are consistent
> with a scenario where high-pT eta production in nuclear collisions at RHIC
> is largely unaffected by initial-state effects, but where light-quark mesons
> (pi0;eta) are equally suppressed due to final-state interactions of the
> parent partons in the dense medium produced in Au+Au reactions.
>
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