Related papers: Gluon saturation effects on single spin asymmetrie…
Measurements by the STAR collaboration of the cross section and transverse single spin asymmetry (SSA) of neutral pion production at large Feynman x (x_F) in pp-collisions at \sqrt{s}=200 GeV were reported previously. The x_F dependence of…
First measurements of large Feynman x (x_F) neutral pion production in polarized proton collisions at sqrt(s)=200 GeV were reported previously. Cross section measurements at <eta>=3.3 and 3.8$ and analyzing power (A_N) measurements at…
We calculated the single spin asymmetry in the inclusive pion production in the fragmentation region of transversely polarized proton-proton collisions. We generated the asymmetry at the level of fragmentation function (Collins effect) by…
We present a phenomenological analysis of available data on single spin asymmetries for pion and $D$ meson production in proton-proton collisions at RHIC within the color gauge invariant generalized parton model (CGI-GPM), which includes…
Single transverse spin asymmetry for the pion production in pp and ep collisions is studied in the framework of collinear factorization. The soft-gluon pole contributions with twist-3 distribution and fragmentation functions are identified…
Measurements by the STAR collaboration of neutral pion production at large Feynman x (x_F) in the first polarized proton collisions at $\sqrt{s}=200$ GeV were reported previously. Cross sections measured at $\eta=3.3$, 3.8 and 4.0 are found…
The role of intrinsic transverse momentum both in unpolarized and polarized processes is discussed. We consider inclusive cross sections for pion production in hadronic collisions and for Drell-Yan processes; the results are compared with…
We study a weighted asymmetry in the azimuthal distribution of photon-jet pairs produced in the process p^\uparrow p --> \gamma jet X with a transversely polarized proton. We focus on the contribution of the Sivers effect only, considering…
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…
In order to understand the gluon contribution to the nucleon spin, some experiments can study the production of hadrons at high transverse momemtum from lepton-nucleon or nucleon-nucleon scattering. RHIC has recently measured such double…
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…
We investigate the Collins effect in single spin asymmetries (SSAs) of the $p^{\uparrow}p \to \pi X$ process, by taking into account the transverse momentum dependence of the microscopic sub-processes cross sections, with the transverse…
We present a study of transverse single-spin asymmetries (SSAs) in $p^\uparrow p\to J/\psi\,X$ and $p^\uparrow p\to D X$ within the framework of the generalized parton model (GPM), which includes both spin and transverse momentum effects,…
We compute the twist-three fragmentation contribution to the transverse single spin asymmetry (SSA) in light hadron production $p^\uparrow p\to hX$ and $p^\uparrow A\to hX$ including the gluon saturation effect in the unpolarized…
Mechanism for the single transverse spin asymmeties in the pion production, p^\uparrow + p'\to \pi(\ell_T) + X, and the \Lambda hyperon polarization, p + p' \to \Lambda^\uparrow (\ell_T)+ X, is investigated in the framework of QCD…
We study the transverse single spin asymmetry in direct photon production in pA collisions with incoming protons being transversely polarized. To facilitate the calculation, we formulate a hybrid approach in which the nucleus is treated in…
The single transverse spin asymmetry in D meson production at RHIC can provide a clean measure of the gluon Sivers distribution function. At intermediate rapidity, D production is largely dominated by the elementary gg -> c c-bar channel,…
We investigate the resummation of large logarithmic perturbative corrections to the partonic cross sections for single-inclusive high-p_T hadron production in collisions of transversely polarized hadrons. We perform the resummation to…
We study the effects of gluon saturation on pion production in high energy proton-nucleus collisions using the color glass condensate model. At high p_perp, we show that the p_perp-distribution of gluons behaves as ~ 1/(p_perp^7) in…
In a perturbative QCD approach, with inclusion of spin and transverse momentum effects, experimental data on azimuthal asymmetries observed in polarized semi-inclusive deeply inelastic scattering and e+ e- annihilations can be used to…