Gluon shadowing and nuclear entanglement entropy

Relying on previous results, that link entanglement entropy and parton distribution functions in deep inelastic scattering, and focusing on the small Bjorken scaling region we present here indications that gluon shadowing might indeed be explained as due to a depletion of the entanglement entropy, between observed and unobserved degrees of freedom, per nucleon within a nucleus, with respect to the free nucleon. We apply to gluon shadowing the general Page approach to the calculation of the entanglement entropy in bipartite systems, giving physical motivations of the results.

Charm and Beauty Production Cross-Section Measurements in Deep Inelastic Electron-Proton Scattering at HERA

The open charm and beauty production cross-sections in the deep inelastic ep scattering (DIS) at HERA from the H1 and ZEUS Collaborations are combined. Reduced cross-sections are obtained in the kinematic range of negative four-momentum transfer squared of a photon 2.5≤ Q2 ≤2000 GeV2 and the Bjorken scaling variable 3×10¬5 ≤ xBj ≤5×10¬2. The different charm- and beauty-tagging methods are used for the heavy-flavor production study in DIS. The combined method accounts for the correlations of systematic uncertainties, as well as statistical uncertainties among the different datasets. Perturbative QCD (pQCD) calculations are compared to the measured combined data. A NLO QCD analysis is performed using these data together with the combined inclusive deep inelastic scattering cross-sections from HERA. The running charm- and beauty-quark masses are determined as mc(mc) = 1,290+0,046−0,041(exp /fit)+0,062−0,014(model)+0,03−0,031(parametrization) GeV and mb(mb) = 4,049+0,104−0,109(exp /fit)+0,090−0,032(model)+0,001−0,031(parametrization) GeV.

Measurement of multiplicities of charged hadrons, pions and kaons in DIS at COMPASS

Precise measurements of multiplicities of charged hadrons, pions and kaons in deep inelastic scattering were performed. The data were obtained by the COMPASS Collaboration by scattering 160 GeV muons off an isoscalar 6LiD target. The results were obtained in three-dimensional bins of the Bjorken scaling variable x, the relative virtual-photon energy y, and the fraction z of the virtual-photon energy carried by the produced hadron. A leading-order pQCD analysis was performed using the pion multiplicity results to extract quark fragmentation functions into pions. The results for the sum of the z-integrated multiplicities for pions and for kaons, differ from earlier results from the HERMES experiment. The results from the sum of the z-integrated K+ and K- multiplicities at high x point to a value of the non-strange quark fragmentation function larger than obtained by the earlier DSS fit.

A Measurement of g2p at Low Q2

Jefferson Lab has been at the forefront of a program to study the polarized structure of nucleons using electron scattering. Measurements of the spin dependent structure functions, [Formula: see text] and [Formula: see text], have proven to be powerful tools in testing and understanding QCD. The neutron structure function [Formula: see text] has been measured extensively in Hall A at Jefferson Lab over a wide range of [Formula: see text], but data for [Formula: see text] remains scarce. This docment will discuss the [Formula: see text] experiment, which ran in Hall A at Jefferson Lab in the spring of 2012, and will provide the first measurement of [Formula: see text] in the resonance region; covering [Formula: see text] GeV2. The 0[Formula: see text] moment of [Formula: see text] provides a test of the Burkhardt-Cottingham sum rule, which states that the integral of [Formula: see text] over the Bjorken scaling variable [Formula: see text] goes to zero. This sum rule, valid for all values of [Formula: see text], has been satisfied for the neutron, but a violation is suggested for the proton at high [Formula: see text]. The 2[Formula: see text] moment allows for a benchmark test of [Formula: see text]PT at low [Formula: see text]. Specifically, the behavior of the longitudinally-transverse spin polarizability ([Formula: see text]), as [Formula: see text]PT calculations of this quantity deviate significantly from the measured neutron data. This document will discuss the current status of the analysis along with preliminary results.

APPLIED HIGH ENERGY QCD

This review stresses the theoretical elements that underlie a wide range of phenomenological studies of high-energy QCD, which include both soft and hard processes. After a brief introduction to the basics of QCD, various aspects of QCD-based phenomenology are covered: color transparency, hadronization of color charges, Regge phenomenology, parton model, Bjorken scaling and its violation, DGLAP evolution equation, BFKL formalism, GLR-MQ evolution equation and saturation. In the last part of the review, we employ the light-cone dipole formalism to describe deep inelastic lepton scattering, Drell — Yan processes, direct photon production, diffraction, quark and gluon shadowing in nuclei, the Cronin effect and nuclear broadening.

EVALUATION OF CHARGED CURRENT NEUTRINO–NUCLEON INTERACTION CROSS-SECTION

The charged current neutrino–nucleon interaction cross-section is evaluated using Thermodynamical Bag Model (TBM) in the neutrino energy range 1 < Eν < 200 GeV with the value of the four-momentum transfer squared 0.1 < Q2 < 20 GeV 2 and the Bjorken variable 0.1 < x < 0.5. The hadronic current carries the linear moments of the reaction that depend on the Bjorken scaling variable x as well as the four-momentum transfer. The results obtained have been compared with the experimental values.