3 research outputs found
Enhanced charm hadroproduction due to nonlinear corrections to the DGLAP equations
We have studied the effects of nonlinear scale evolution of the parton
distribution functions to charm production in collisions at center-of-mass
energies of 5.5, 8.8 and 14 TeV. We find that the differential charm cross
section can be enhanced up to a factor of 4-5 at low . The enhancement is
quite sensitive to the charm quark mass and the renormalization/factorization
scales.Comment: 4 pages, 3 eps-figures. To appear in the proceedings of the
seventeenth international conference on Ultra-Relativistic Nucleus-Nucleus
Collisions (Quark Matter 2004
Hard probes in heavy ion collisions at the LHC: PDFs, shadowing and collisions
This manuscript is the outcome of the subgroup ``PDFs, shadowing and
collisions'' from the CERN workshop ``Hard Probes in Heavy Ion Collisions at
the LHC''. In addition to the experimental parameters for collisions at
the LHC, the issues discussed are factorization in nuclear collisions, nuclear
parton distributions (nPDFs), hard probes as the benchmark tests of
factorization in collisions at the LHC, and semi-hard probes as
observables with potentially large nuclear effects. Also, novel QCD phenomena
in collisions at the LHC are considered. The importance of the
program at the LHC is emphasized.Comment: The writeup of the working group "PDFs, shadowing and
collisions" for the CERN Yellow Report on Hard Probes in Heavy Ion Collisions
at the LHC, 121 pages. Subgroup convenors: K.J. Eskola, J.w. Qiu (theory) and
W. Geist (experiment). Editor: K.J. Eskol
D meson enhancement in pp collisions at the LHC due to nonlinear gluon evolution
When nonlinear effects on the gluon evolution are included with constraints
from HERA, the gluon distribution in the free proton is enhanced at low
momentum fractions, x < 0.01, and low scales, Q^2 < 10 GeV^2, relative to
standard, DGLAP-evolved, gluon distributions. Consequently, such gluon
distributions can enhance charm production in pp collisions at center of mass
energy 14 TeV by up to a factor of five at midrapidity, y \sim 0, and
transverse momentum p_T -> 0 in the most optimistic case. We show that most of
this enhancement survives hadronization into D mesons. Assuming the same
enhancement at leading and next-to-leading order, we show that the D
enhancement may be measured by D^0 reconstruction in the K^-\pi^+ decay channel
with the ALICE detector.Comment: 15 pages, 4 figures, final version accepted by J. Phys.