3,366 research outputs found
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 =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 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 and Recent Developments in Correlation
Some of the puzzles on hadron production at intermediate 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
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