Gluon shadowing and unitarity effects

New data from HERA experiment on deep inelastic scattering have been used to parametrize nucleon and Pomeron structure functions. Within the Gribov theory, the parameterizations were employed to calculate gluon shadowing for various heavy ions. The latter was compared with predictions from other models. Calculations of multiplicity reduction due to gluon shadowing for d+Au collisions at forward rapidities at $\sqrt{s}$=200 GeV are in good agreement with BRAHMS data on the nuclear modification factor.Comment: 5 pages, 4 figures, submitted to Acta Physica Hungarica A, Quark Matter 2005 poster session proceedings; minor changes in the text adde

Recent results from BRAHMS

The BRAHMS collaboration ended its data collection program in 2006. We are now well advanced in the analysis of a comprehensive set of data that spans systems ranging in mass from p+p to Au+Au and in energy from $\sqrt{s_{NN}} = 62.4$ to 200 GeV. Our analysis has taken two distinct paths: we explore the rapidity dependence of intermediate and high-transverse-momentum, identified-particle production, thus helping to characterize the strongly-interacting quark-gluon plasma (sQGP) formed at RHIC; we also explore particle yields at lower transverse momentum to develop a systematic understanding of bulk particle production at RHIC energies.Comment: 8 pages, 5 figures, presented at the 20th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions, "Quark Matter 2008", Jaipur, India, February 4-10, 200

High pt Measurements at the CERN SPS

The current experimental situation concerning high pt observables at the CERN SPS is reviewed. Recent data from the NA45, NA49 and NA57 collaborations are discussed and compared to earlier measurements by WA98 and NA45 at the same center-of-mass energies, as well as to measurements at the higher energies by the RHIC experiments. The observables include new p+p, A+A spectra, nuclear modification factors (R_AA, R_CP), two particle azimuthal correlations, and baryon to meson ratios at moderately high pt. Generally, the interpretation of the SPS data suffers from the lack of reliable baseline measurements (p+p and p+A). However, the overall picture that is emerging suggests that already at SPS energies medium effects similar to those observed at RHIC are present.Comment: Invited plenary talk at the Hard Probes Conference Asilomar, CA, June 9-16, 2006, to be published in Nucl. Phys.

Resolutions of Several Puzzles at Intermediate pTp_T and Recent Developments in Correlation

Some of the puzzles on hadron production at intermediate $p_T$ found at RHIC are explained as natural consequences of parton recombination. In that framework for hadronization the correlation among hadrons produced in jets can be calculated. Some new results on both near-side and away-side jet structures are presented.Comment: 5 pages in LaTeX , 0 figures. Talk given at Quark Matter 200

Charm Quark Energy Loss in QCD Matter

The energy loss of heavy quarks in a quark-gluon plasma of finite size is studied within the light-cone integral approach. A simple analytical formulation of the radiative energy loss of heavy quarks is derived. This provides a convenient way to quantitatively estimate the quark energy loss. Our results show that if the energy of a heavy quark is much larger than its mass, the radiative energy loss approaches the radiative energy loss of light quarks.Comment: 4 pages, 2 figures. Accepted for publication in European Physical Journal