Related papers: Comparison between the various descriptions for ch…
We consider the fragmentation of heavy quarks into heavy-flavoured hadrons, specifically the production of charmed mesons in $e^+e^-$ collisions, at different centre-of-mass energies. We focus our attention on the ratio of moments of the…
We present the matching relations of the variable flavor number scheme at next-to-leading order, which are of importance to define heavy quark partonic distributions for the use at high energy colliders such as Tevatron and the LHC. The…
The cross section for the photoproduction of large-p_T J/psi mesons at HERA is calculated at next-to-leading order, adopting a perturbative approach to describe the fragmentation of charm quarks and gluons into J/psi mesons. We treat the…
Contributions through second order, $O(\alpha ^2_s)$, in perturbative quantum chromodynamics are calculated analytically for inclusive associated production of a prompt photon and a charm quark at large values of transverse momentum in high…
There are different approaches for diffractive photoproduction of charmonia. Recently, a new approach is proposed, in which charm quarks are taken as heavy quarks and the nonperturbative effect related to charmonia can be handled with…
A simple parametrisation of H1 and ZEUS data at HERA is given for the ranges in x and Q^2 of 10^{-4} - 5.10^{-2} and 5 - 250 GeV^2, respectively. This empirical expression is based on a strikingly similar dependence of the average charged…
A study of the $J/\psi$-meson production at large transverse momentum in high energy $\gamma p$ collisions via the charm quark excitation in a photon is presented. Based on perturbative QCD and the nonrelativistic quark model, our…
We calculated the contribution of the photon hadronic component in the charmed structure function of the leptoproduction. The contribution comes from scattering of the c quarks of the virtual photon on the quarks and gluons of the proton.…
The production of charmed and beauty hadrons in proton-proton and proton-antiproton collisions at high energies is analyzed within the modified quark-gluon string model (QGSM) including the internal motion of quarks in colliding hadrons. It…
We report on the extraction of the structure functions F_2 and Delta xF_3 = xF_3(nu)-xF_3(nubar) from CCFR nu_mu-Fe and nubar_mu-Fe different ial cross sections. The extraction is performed in a physics model independent (PMI) way. This…
We study systematically the sensitivity of the photon structure function data on the gluon contents of the photon, by using the leading order Altarelli--Parisi (AP) equations. Charm quark contribution is studied in the quark parton model…
Proton-proton collisions at the LHC provide the ground for tests of the strong interactions through the study of the production mechanisms for quarkonia and hadrons containing charm or beauty flavours. This review addresses recent results…
We consider the possibility of a direct determination of the polarized gluon density in the proton using charm production with polarized beams at HERA. We study total cross sections and distributions at leading order using different…
The last two decades have seen a growing trend towards the experimental efforts at the electron-proton collider HERA in which have collected high precision data on the spectrum of leading neutron (LN) and leading-proton (LP) carrying a…
New Results on the measurement of the proton structure function F_2(x,Q^2) are reported for momentum transfers squared Q^2 >= 1.5 GeV^2 and Bjorken x >= 3.5 10^{-5} using data collected by the HERA experiments H1 and ZEUS in 1994. F_2…
We evaluate nuclear shadowing of the total cross section of charm particles production in DIS within the framework of the Gribov theory of nuclear shadowing using as input the recent QCD Pomeron parton density analysis of the HERA…
The charm contribution to the proton structure, F_2^c(x,Q^2), is determined using the inclusive cross sections of D*(2010) meson production in deep-inelastic scattering. The cross section measurement covers the region 5 < Q2 < 1000 GeV2 in…
We present the complete NLO QCD analysis of the photon structure functions $F_2^\gamma(x,Q^2)$ and $F_L^\gamma(x,Q^2)$ for a real photon target. In particular we study the heavy flavor content of the structure functions which is due to two…
The FONLL general-mass variable-flavour number scheme provides a framework for the matching of a calculation in which a heavy quark is treated as a massless parton to one in which the mass dependence is retained throughout. We describe how…
In this presentation, I discussed a) the charm total cross-section and its comparisons to measurements at other beam energies and pQCD calculations; b) the semileptonic decay of charmed hadrons and the sensitivity of non-photonic leptons to…