Search

We analyze the connection between $p_T$ and multiplicity distributions in a statistical framework. We connect the Tsallis parameters, $T$ and $q$, to physical properties like average energy per particle and the second scaled factorial moment, $F_2=\langle n(n-1) \rangle / {\langle n \rangle}^2$, measured in multiplicity distributions. Near and far from equilibrium scenarios with master equations for the probability of having $n$ particles, $P_n$, are reviewed based on hadronization transition rates, $\mu_n$, from $n$ to $n+1$ particles., Comment: Talk given by T.S.Biro at SQM 2016, Berkeley, 4 pages

We demonstrate that charged pion spectra in central and peripheral PbPb collisions at $\sqrt{s}$ = 2.76 ATeV obtained via perturbative quantum chromodynamics improved parton model calculations [17] can be approximated by the Tsallis distribution for transverse momenta $p_T \geq$ 4 GeV/c. Then, we propose a model in which, hadrons produced in heavy-ion collisions stem either from "soft" or "hard" processes, and are distributed according to the Tsallis distribution in both types of yields. We describe transverse spectra as well as azimuthal anisotropy ($v_2$) of charged hadrons stemming from various centrality PbPb collisions at $\sqrt{s}$ = 2.76 ATeV [40,41,42] analytically. In addition, we find that the anisotropy decreases for more central collisions., Comment: 10 pages, 4 figures, 4 tables

Resonance production and decay into pion pairs is simulated in a non-extensive quark matter with multi-particle interactions. Final state pion spectra are found to take the form of the Tsallis distribution, in accordance with measurements. It has also been shown that, if a large number of particles with these multi-particle interactions are constrained to a constant energy hyper-surface in phase space, the one-particle distribution is the Tsallis distribution.

We calculate nuclear modification factors and pseudorapidity asymmetries in $pA$ and $dA$ collisions in a pQCD-improved parton model. With the calculations tuned to describe existing spectra from $pp$ collisions and asymmetric systems at midrapidity and large rapidities at FNAL and RHIC energies, we make predictions for LHC energies., Comment: 8 pages; 4 figures. To appear in the proceedings of the 3rd International Workshop on High-PT Physics at the LHC, March, 16-19, 2008, Tokaj, Hungary

We calculate pseudorapidity ($\eta$) asymmetry in $pA$ and $dA$ collisions in a pQCD-improved parton model. With the calculations tuned to describe existing spectra from $pp$ collisions and asymmetric systems at midrapidity and large rapidities at FNAL and RHIC energies, we investigate the roles of nuclear shadowing and multiple scattering on the observed asymmetry. Using this framework, we make predictions for pseudorapidity asymmetries at high $p_T$ and large $\eta$ in a wide range of energies up to LHC., Comment: 10 pages, 8 figures; expanded description of model, added new references

A third workshop on small-x physics, within the Small-x Collaboration, was held in Hamburg in May 2004 with the aim of overviewing recent theoretical progress in this area and summarizing the experimental status., Comment: Edited by: Goesta Gustafson, Hannes Jung, Leif Joensson, Leif Loennblad

In this talk we present a perturbative QCD improved parton model calculation for light meson production in high energy heavy ion collisions. In order to describe the experimental data properly, one needs to augment the standard pQCD model by the transverse momentum distribution of partons ("intrinsic k_T"). Proton-nucleus data indicate the presence of nuclear shadowing and multiscattering effects. Further corrections are needed in nucleus-nucleus collisions to explain the observed reduction of the cross section. We introduce the idea of proton dissociation and compare our calculations with the SPS and RHIC experimental data., Comment: Talk presented by G. Papp at Zakopane 2001 School, Zakopane, 2001 June; 10 pages with 3 EPS figures