Related papers: Gluon Sivers function and transverse single spin a…
We present a calculation of the twist-3 generalized parton distributions (GPDs) for gluons in the proton. Our analysis is performed within a light-front constituent model where the proton is treated as a two-body state of a spin-1 gluon and…
We calculate the gluon gravitational form factors (GFFs) of the proton using a light-front spectator model based on soft-wall AdS/QCD, where the active parton is a gluon. The model parameters are determined by fitting the unpolarized gluon…
Within a TMD approach we discuss the impact of quasi-real (Weizs\"acker-Williams) photon contribution to the transverse single-spin asymmetry, $A_N$, for the inclusive process $\ell p^\uparrow \to \pi\, X$. This study extends a previous one…
A dominant QCD mechanism for the single transverse-spin asymmetry in hard processes is induced by the twist-3 quark-gluon correlations inside nucleon, combined with the soft-gluonic poles to produce the interfering phase for the associated…
We consider within a generalized QCD factorization approach, the high energy inclusive polarized process p p --> pion + X, including all intrinsic partonic motions. Several new spin and k_T-dependent soft functions appear and contribute to…
A measurement of the electroproduction of photons off protons in the deeply inelastic regime was performed at Jefferson Lab using a nearly 6-GeV electron beam, a longitudinally polarized proton target and the CEBAF Large Acceptance…
We have measured the spin-dependent structure function $g_1^p$ in inclusive deep-inelastic scattering of polarized muons off polarized protons, in the kinematic range $0.003 < x < 0.7$ and $1 GeV^2 < Q^2 < 60 GeV^2$. A next-to-leading order…
Recently, it has been shown, contrary to previous beliefs, that the k_T distribution of quarks in a transversely polarized proton can be asymmetric. This ``Sivers effect'' had already been used to explain transverse single spin asymmetries…
We study the single-spin (left-right) asymmetry in single-inclusive pion production in hadronic scattering. This asymmetry is power-suppressed in the transverse momentum of the produced pion and can be analyzed in terms of twist-three…
Measurements of the production of forward high-energy pi0 mesons from transversely polarized proton collisions at \sqrt{s}=200 GeV are reported. The cross section is generally consistent with next-to-leading order perturbative QCD…
New results on single spin asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarised LiD target are presented. The data were taken in the years 2002, 2003 and 2004 with the COMPASS…
We analyze in the framework of pQCD the properties of the single spin asymmetry in heavy flavor production by linearly polarized photons. At leading order, the parallel- perpendicular asymmetry in azimuthal distributions of both charm and…
Within the collinear twist-3 framework, we study the single-spin asymmetry (SSA) in collisions between unpolarized protons and transversely polarized protons with focus on the fragmentation term. The fragmentation mechanism must be analyzed…
One of the important objectives of the COMPASS experiment (SPS, CERN) \cite{Abbon:2007pq} is the exploration of the transverse spin structure of the nucleon via spin dependent azimuthal asymmetries in single-hadron production in deep…
We study the single-spin asymmetries of pions produced in semi-inclusive deep-inelastic scattering on the longitudinally polarized nucleon targets. We particularly consider the effects of the twist-3 transverse-momentum dependent…
In this paper we briefly review the transverse momentum dependent generalized parton model and its application to the study of azimuthal asymmetries in the distribution of leading hadrons (mainly pions) inside large transverse momentum jets…
Inspired by the recent near-threshold $J/\psi$ photoproduction measurements, we discuss gluon gravitational form factors (GFFs) and internal properties of the proton. This work presents a complete analysis of the proton gluon GFFs…
In this paper we study the single spin asymmetry $A_{UT}^{\sin(\phi_h-\phi_S)}$ of a single hadron production in semi-inclusive deep inelastic scattering (SIDIS) within the framework of transverse momentum dependent (TMD) factorization up…
We propose that back-to-back correlations in azimuthal angle of jets produced in collisions of unpolarized with transversely polarized proton beams could be used to determine Sivers functions. The corresponding single-spin asymmetry is not…
We compute the transverse single spin asymmetry in light hadron production $p^\uparrow p\to hX$ and $p^\uparrow A\to hX$ including the gluon saturation effect in the unpolarized nucleon/nucleus. In the forward (large-$x_F$) region, the…