High-p~ T Pion Production in Heavy-Ion Collisions (original) (raw)
High-p_T Pion Production in Heavy-Ion Collisions at RHIC energies
Perturbative QCD results on π production are presented in proton-proton, protonnucleus and nucleus-nucleus collisions from CERN SPS up to RHIC energy. A K jet (s, p T , Q) factor obtained from jet production is applied to perform nextto-leading order calculations. Using the intrinsic transverse momentum (k T ) we determined transverse momentum spectra for pions in wide energy region. We have investigated nuclear multiscattering and the Cronin effect at RHIC energies.
High-pT pion and kaon production in relativistic nuclear collisions
Physical Review C, 2002
High-pT pion and kaon production is studied in relativistic proton-proton, proton-nucleus, and nucleus-nucleus collisions in a wide energy range. Cross sections are calculated based on perturbative QCD, augmented by a phenomenological transverse momentum distribution of partons ("intrinsic kT "). An energy dependent width of the transverse momentum distribution is extracted from pion and charged hadron production data in proton-proton/proton-antiproton collisions. Effects of multiscattering and shadowing in the strongly interacting medium are taken into account. Enhancement of the transverse momentum width is introduced and parameterized to explain the Cronin effect. In collisions between heavy nuclei, the model over-predicts central pion production cross sections (more significantly at higher energies), hinting at the presence of jet quenching. Predictions are made for proton-nucleus and nucleus-nucleus collisions at RHIC energies.
Perturbative QCD results on pion production in pp, pA and AA collisions
We summarize new pQCD results on pion production in protonproton (pp), proton-nucleus (pA) and nucleus-nucleus (AA) collisions. Our calculation introduces intrinsic parton transverse momentum (k T ) and is performed effectively at next-to-leading order (NLO), applying a K factor extracted for jet events. Two different factorization scales, Q = p T,jet /2 and p T,jet are used. Experimental data in pA collisions imply a preference for the latter choice at NLO level. We display our results at CERN SPS for AA collisions.
Journal of Physics G: Nuclear and Particle Physics, 2002
The nature of transverse momentum dependence of the inclusive cross-sections for secondary pions produced in high energy hadronic(P P ), hadronuclear(P A) and nuclear(AA) collisions has here been exhaustively investigated for a varied range of interactions in a unified way with the help of a master formula. This formula evolved from a new combination of the basic Hagedorn's model for particle(pion) production in PP scattering at ISR range of energies, a phenomenological approach proposed by Peitzmann for converting the results of N N (P P ) reactions to those for either P A or AA collisions, and a specific form of parametrization for mass number-dependence of the nuclear cross sections. This grand combination of models(GCM) is then applied to analyse the assorted extensive data on various high energy collisions. The nature of qualitative agreement between measurements and calculations on both the inclusive cross-sections for production of pions, and some ratios of them as well, is quite satisfactory. The modest successes that we achieve here in dealing with the massive data-sets are somewhat encouraging in view of the diversity of the reactions and the very wide range of interaction energies.
Physics Letters B, 2016
The production of charged pions, kaons and (anti)protons has been measured at mid-rapidity (-0.5 < y < 0) in p-Pb collisions at √ s NN = 5.02 TeV using the ALICE detector at the LHC. Exploiting particle identification capabilities at high transverse momentum (p T ), the previously published p T spectra have been extended to include measurements up to 20 GeV/c for seven event multiplicity classes. The p T spectra for pp collisions at √ s = 7 TeV, needed to interpolate a pp reference spectrum, have also been extended up to 20 GeV/c to measure the nuclear modification factor (R pPb ) in nonsingle diffractive p-Pb collisions. At intermediate transverse momentum (2 < p T < 10 GeV/c) the proton-to-pion ratio increases with multiplicity in p-Pb collisions, a similar effect is not present in the kaon-to-pion ratio. The p T dependent structure of such increase is qualitatively similar to those observed in pp and heavy-ion collisions. At high p T (> 10 GeV/c), the particle ratios are consistent with those reported for pp and Pb-Pb collisions at the LHC energies. At intermediate p T the (anti)proton R pPb shows a Cronin-like enhancement, while pions and kaons show little or no nuclear modification. At high p T the charged pion, kaon and (anti)proton R pPb are consistent with unity within statistical and systematic uncertainties.