175 research outputs found
Diffractive dissociation in high energy pp collisions in Additive Quark Model
High energy (CERN SPS and LHC) () scattering is treated in the
framework of Additive Quark Model together with Pomeron exchange theory. The
reasonable agreement with experimental data is achieved both for the elastic
scattering and for the diffractive dissociation with natural parameters for the
strong matter distribution inside proton.Comment: 12 pages, 4 figures, 1 table. arXiv admin note: text overlap with
arXiv:1406.142
Heavy Quark Production in Parton Model and in QCD
The cross sections of heavy quark production in collision and for their
photo- and electroproduction are calculated in the framework of QCD. The
virtual nature of the interacting gluons as well as their transverse motion and
different polarizations are taken into account. The obtained cross sections
exhibit more rapid growth with the initial energy than the parton model
predictions and the distributions of produced heavy quarks are more
smooth.Comment: 12 pages, LaTeX, 10 uuencoded-compressed-tar fig
Treatment of heavy quarks in QCD
We show that to correctly describe the effects of the heavy-quark mass, m_h,
in DGLAP evolution, it is necessary to work in the so-called `physical' scheme.
In this way, we automatically obtain a smooth transition through the
heavy-quark thresholds. Moreover, we show that to obtain NLO accuracy, it is
sufficient to account for the heavy-quark mass, m_h, just in the LO (one-loop)
splitting function. The use of the MS-bar factorisation scheme is not
appropriate, since at NLO we deal with a mixture of quarks and gluon (that is,
the mass of the heavy parton is not well-defined). The formulae for the
explicit m_h dependence of the splitting functions, and for alpha_s, are
presented.Comment: 14 pages, 3 figures, references updated, version to be published in
EPJ
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