We discuss baryon production in the nucleon fragmentation region in deep inelastic scattering. The dependence of the nucleon spectra on Bjorken-x is evaluated within the parton model and in QCD, and ways to look for the break-down of the DGLAP approximation via baryon production are suggested. We argue also that the leading neutron production in these small x processes is rather insensitive to ...

We discuss how to extract the polarized parton densities and fragmentation functions in a model independent way from SIDIS, and present results for D + u,d,s. There are two types of processes that give information on polarized parton densities in nucleon. The polarized asymmetry in DIS of longitudinally polarized leptons on longitudinally polarized nucleons: ∆A N = 2y(2− y) 1 + (1− y) ∆σ N σ N ...

Q 2 variation of the nuclear-structure-function ratio F A 2 (x, Q 2)/F D 2 (x, Q 2) is investigated in a parton model with Q 2-rescaling and parton-recombination effects. Calculated results are compared with the NMC (New Muon Collaboration) and the Fermilab-E665 experimental data. We find that our theoretical results show small Q 2 variations and that they are consistent with the data within pr...

In the article, we study single and pair $J/\psi$ hadroproduction in Improved Color Evaporation Model via Parton Reggeization Approach. The last one is based on $k_T$-factorization of hard processes multi-Regge kinematics, Kimber-Martin-Ryskin-Watt model for unintegrated parton distribution functions, effective field theory Reggezied gluons quarks, suggested by L.N. Lipatov. We compare contribu...

It is shown that the Geant4 FTF model, which does not include simulation of hard parton-parton scattering and formation quark-gluon plasma (QGP), describes well NA61/SHINE data on $\pi^-$ meson distributions for interactions at $\sqrt{s_{NN}}=$ 5.2, 6.1, 7.6 8.8 GeV. At higher energies, 11.9 16.8 GeV, model underestimates data. This considered as an indication QGP energies in central collisions...

In a central nucleus-nucleus collision at high-energies, medium partons kicked by a near-side jet acquire a momentum along the jet direction and subsequently materialize as the observed ridge particles. They carry direct information on the early parton momentum distribution which can be extracted by using the ridge data for central AuAu collisions at √ sNN = 200 GeV. The extracted parton moment...

A statistical model for the parton distributions in the nucleon has proven its efficiency in the analysis of deep inelastic scattering data, so we propose to extend this approach to the description of unpolarized fragmentation functions for the octet baryons. The characteristics of the model are determined by using some data on the inclusive production of proton and Λ in unpolarized deep inelas...

The precise combined HERA-I data set, of neutral and charged current inclusive crosssections for ep and e−p scattering, is used as the sole input for a next-to-leading order (NLO) QCD parton distribution function (PDF) fit. The consistent treatment of systematic uncertainties in the combined data and the use of an improved theoretical model that takes into account the quark masses result in a n...

We introduce a transport approach which combines partonic and hadronic degrees of freedom on an equal footing and discuss the resulting reaction dynamics. The initial parton dynamics is modeled in the framework of the parton cascade model, hadronization is performed via a cluster hadroniza-tion model and configuration space coalescence, and the hadronic phase is described by a microscopic hadro...

We present a model calculation of the generalized parton distributions where the nucleon is described by a quark core surrounded by a mesonic cloud. In the one-meson approximation, we expand the Fock state of the physical nucleon in a series involving a bare nucleon and two-particle, meson-baryon, states. We discuss the role of the different Fock-state components of the nucleon by deriving a co...