5,149 research outputs found
NA49 Energy Scan Results for Central Lead-Lead Collisions at the CERN SPS
The energy dependence of hadron production in central Pb-Pb collisions at SPS
energies is presented and compared with data at lower and higher energies and
with results from p-p interactions. It is observed that there is little change
in transverse activity in the SPS energy range, that there is a steepening rate
of increase of pion production and that the K+/pi+ ratio exhibits a sharp peak
located at about 30 AGeV. The Lambda/pi ratio also shows a pronounced maximum
which is weaker in Ksi/pi and absent in Omega/pi.Comment: To appear in the proceedings of the 39th Rencontres de Moriond on QCD
and High-Energy Hadronic Interactions, La Thuile, March 28 - April 4, 200
Future measurements of alpha_s and xg from scaling violations at HERA
Results are presented of a study of the experimental and theoretical accuracy
one may achieve at HERA in measuring the strong coupling constant alpha_s and
the gluon distribution from scaling violations of F2 structure functions.Comment: 7 pages, 2 figures. Latex source file and 2 separate .ps files. Talk
presented at the DIS97 workshop, Chicago, April 14-18 199
Error Estimates on Parton Density Distributions
Error estimates on parton density distributions are presently based on the
traditional method of least squares minimisation and linear error propagation
in global QCD fits. We review the underlying assumptions and the various
mathematical representations of the method and address some technical issues
encountered in such a global analysis. Parton distribution sets which contain
error information are described.Comment: Latex, 12 pages, 5 figures. Needs iopart.cls and iopart12.clo.
Presented at New Trends in HERA Physics 2001, Ringberg Castle, Tegernsee,
Germany, June 17-22, 200
Inclusive Deep Inelastic Scattering at HERA and related phenomenology
Recent measurements of inclusive deep inelastic scattering differential
cross-section in the range 1.5 \gev2\le Q^2\le 30000 \gev2 and 5\cdot
10^{-6}\le x\le 0.65 are presented. Phenomenological analyses performed from
these measurements are also described.Comment: 14 page
Heavy Quark Production in the ACOT Scheme Beyond NLO
We analyze the properties of the ACOT scheme for heavy quark production and
make use of the MS-Bar massless results at NNLO and N3LO for the structure
functions F2 and FL in neutral current deep-inelastic scattering to estimate
the higher order corrections. The dominant heavy quark mass effects at higher
orders can be taken into account using the massless Wilson coefficients
together with an appropriate slow-rescaling prescription implementing the phase
space constraints. Combining the exact ACOT scheme at NLO with these
expressions should provide a good approximation to the full calculation in the
ACOT scheme at NNLO and N3LO.Comment: 4 pages, 2 figures. Presented at DIS12, March 2012, Bonn, German
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