3 research outputs found
Nuclear suppression of dileptons at forward rapidities
Data from E772 and E866 experiments on the Drell-Yan process exhibit a
significant nuclear suppression at large Feynman xF. We show that a
corresponding kinematic region does not allow to interpret this as a
manifestation of coherence or a Color Glass Condensate. We demonstrate,
however, that this suppression can be treated alternatively as an effective
energy loss proportional to initial energy. To eliminate suppression coming
from the coherence, we perform predictions for nuclear effects also at large
dilepton masses. Our calculations are in a good agreement with available data.
Since the kinematic limit can be also approached in transverse momenta pT, we
present in the RHIC energy range corresponding predictions for expected
large-pT suppression as well. Since a new experiment E906 planned at FNAL will
provide us with more precise data soon, we present also predictions for
expected large-xF nuclear suppression in this kinematic region.Comment: 6 pages, 4 figures. Talk given at the International Nuclear Physics
Conference (INPC-2010), Vancouver, Canada July 4 - 9, 201
New parton distributions in fixed flavour factorization scheme from recent deep-inelastic-scattering data
We present our QCD analysis of the proton structure function
to determine the parton distributions at the next-to-leading order (NLO). The
heavy quark contributions to , with = , have been
included in the framework of the `fixed flavour number scheme' (FFNS). The
results obtained in the FFNS are compared with available results such as the
general-mass variable-flavour-number scheme (GM-VFNS) and other prescriptions
used in global fits of PDFs. In the present QCD analysis, we use a wide range
of the inclusive neutral-current deep-inelastic-scattering (NC DIS) data,
including the most recent data for charm , bottom , longitudinal
structure functions and also the reduced DIS cross sections
from HERA experiments. The most recent HERMES data for
proton and deuteron structure functions are also added. We take into account
ZEUS neutral current DIS inclusive jet cross section data from HERA
together with the recent Tevatron Run-II inclusive jet cross section data from
CDF and D{\O}. The impact of these recent DIS data on the PDFs extracted from
the global fits are studied. We present two families of PDFs, {\tt KKT12} and
{\tt KKT12C}, without and with HERA `combined' data sets on DIS. We
find these are in good agreement with the available theoretical models.Comment: 23 pages, 26 figures and 4 tables. V3: Only few comments and
references added in the replaced version, results unchanged. Code can be
found at http://particles.ipm.ir/links/QCD.ht