Rapidity and species dependence of particle production at largetransverse momentum for d+Au collisions at psNN = 200 GeV
We determine rapidity asymmetry in the production of charged pions, protons and anti-protons for large transverse momentum (p{sub T}) for d+Au collisions at {radical}s{sub NN} = 200 GeV. The rapidity asymmetry is defined as the ratio of particle yields at backward rapidity (Au beam direction or -ve rapidity) to those at forward rapidity (d beam direction or +ve rapidity). The identified hadrons are measured in the rapidity regions |y| < 0.5 and 0.5 < |y| < 1.0 for the p{sub T} range 2.5 < p{sub T} < 10 GeV/c. We observe significant rapidity asymmetry for charged pion and proton+anti-proton production in both rapidity regions. The asymmetry is larger for 0.5 < |y| < 1.0 than for |y| < 0.5 and is almost independent of particle type. The measurements are compared to various model predictions employing multiple scattering, energy loss, nuclear shadowing, saturation effects, and recombination, and also to a phenomenological parton model. We find that asymmetries are sensitive to model parameters and show model-preference. The rapidity dependence of {pi}{sup -}/{pi}{sup +} and {bar p}/p ratios in peripheral d+Au and forward neutron-tagged events are used to study the contributions of valence quarks and gluons to particle production at high p{sub T}. The results are compared to calculations based on NLO pQCD and other measurements of quark fragmentation functions.
- Research Organization:
- COLLABORATION - STAR
- DOE Contract Number:
- DE-AC02-05CH11231
- OSTI ID:
- 902461
- Report Number(s):
- LBNL-62243; R&D Project: NRNC; BnR: KB0201022; TRN: US0702939
- Country of Publication:
- United States
- Language:
- English
Similar Records
Rapidity and species dependence of particle production at large transverse momentum for d+Au collisions at {radical}(s{sub NN})=200 GeV
Identified haron spectra at large transerve momentum in p+p and d+Au collisions at {radical}{ovr s}{sub NN} = 200 GeV.