相关论文: JAM small-$x$ helicity phenomenology
We construct a numerical solution of the recently-derived large-$N_c \& N_f$ small-$x$ helicity evolution equations with the aim to establish the small-$x$ asymptotics of the quark helicity distribution beyond the large-$N_c$ limit explored…
The quantum statistical parton distributions approach proposed more than one decade ago is revisited by considering a larger set of recent and accurate Deep Inelastic Scattering experimental results. It enables us to improve the description…
The impact of the recent very precise CLAS and COMPASS g1/F1 data on polarized parton densities and higher twist effects is discussed. It is demonstrated that the low Q^2 CLAS data improve essentially our knowledge of higher twist…
We perform the first global QCD analysis of parton distribution functions (PDFs) in the pion, combining $\pi A$ Drell-Yan data with leading neutron electroproduction from HERA within a Monte Carlo approach based on nested sampling.…
We present a comprehensive new global QCD analysis of unpolarized parton distribution functions (PDFs) based upon proton, deuteron and $A\!=\!3$ data, including the latest inclusive deep-inelastic scattering (DIS) measurements from…
We report on the first calculation of the structure function g_1 in polarised deep-inelastic scattering to the third order in massless perturbative QCD. The calculation follows the dispersive approach already used for the corresponding…
A calculation of the non-singlet part of spin dependent structure function, $xg_1^{NS}(x,Q^2)$ and associated sum rule, the Bjorken Sum rule up to next-next-to-leading order(NNLO) is presented. We use a unified approach incorporating Regge…
We review recent developments in the theory and phenomenology of polarized structure functions. We summarize recent experimental data on the proton and deuteron structure function $g_1$, and their impact on the understanding of polarized…
I study the impact of recent measurements performed at the Relativistic Heavy Ion Collider on the determination of helicity-dependent parton distribution functions of the proton. Specifically, I consider: preliminary data on longitudinally…
We discuss the interplay of low-x physics and QCD scaling violations by extending the unified approach describing inclusive structure functions and diffractive production in $\gamma* p$ interactions proposed in previous papers, to large…
This paper contains three parts relating to the nucleon spin structure in a simple picture of the nucleon: (i) The polarized gluon distribution in the proton is dynamically predicted starting from a low scale by using a nonlinear QCD…
We recall our recent description of quark parton densities of the proton at $Q^2=4 GeV^2$ in terms of Fermi-Dirac distributions parametrized with very few free parameters. We have also proposed some simple assumptions to relate unpolarized…
The charm quark structure function $F^c_2$ and the longitudinal structure function $F_l^p$ are directly sensitive to the gluon content of proton and therefore are crucial in understanding of proton structure function, in particular at low…
Predictions for the spin dependent structure function $g_1$ of the nucleon are presented. We use an unified approach incorporating the LO DGLAP evolution and the resummation of double logarithmic terms $ln^2(x)$. We show, that the singular…
The workshop "The Helicity Structure of the Nucleon" (BNL June 5, 2006) was organized as part of the 2006 RHIC & AGS Users' Meeting to review the status of the spin problem and future directions. The presentations can be found at…
The longitudinal double spin asymmetries $A_1^p$ and the spin dependent structure function of the proton $g_1^p$ were extracted from COMPASS data in the region of low Bjorken scaling variable $x$ and low photon virtuality $Q^2$. The data…
We examine methods that have been proposed for determining the helicity structure of decays of new resonances to third generation quarks and/or leptons. We present analytical and semi-analytical predictions and assess the applicability of…
The QCD expectations for the behaviour of the deep inelastic scattering structure functions in the region of small values of the Bjorken parameter $x$ are summarized. The Balitzkij, Lipatov, Fadin, Kuraev (BFKL) equation which sums the…
Parton distributions are constructed in a statistical physical picture of the nucleon. The chiral properties of QCD lead to strong relations between quarks and antiquarks distributions and the importance of the Pauli exclusion principle is…
We initiate the studies on the structural physics of the tower of stable large-$N_c$ mesons through a first computation of the collinear quark-structure of a large-$N_c$ pion using lattice Monte-Carlo methods. We adapt the large-$N_c$…