Related papers: Single Transverse-Spin Asymmetries in Drell-Yan Pr…
New possibilities arising from the availability at GSI of antiproton beams, possibly polarised, are discussed. The investigation of the nucleon structure can be boosted by accessing in Drell-Yan processes experimental asymmetries related to…
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…
We study the semi-inclusive production of real, high-$p_T$, isolated photons in unpolarized and polarized lepton-proton collisions, $\ell p\to \ell\gamma X$. In particular we analyze the transverse nucleon single-spin asymmetry within the…
The Drell-Yan $K$-factors for transversely polarised hadrons are examined. Since transverse spin is peculiar in having no DIS reference point, the effects of higher-order corrections on DY asymmetries are examined via a DIS definition for…
In this paper, we extend the study of Drell-Yan processes with antiproton beams already presented in a previous work. We consider the fully polarized $\bar{p}^\uparrow p^\uparrow \to \mu^+ \mu^- X$ process, because this is the simplest…
We study the scattering of a single parton state with a multi-parton state to derive the complete results of perturbative coefficient functions at leading order, which appear in the collinear factorization for Single transverse-Spin…
We use multi-parton states to examine the leading order collinear factorization of single transverse-spin asymmetries in Drell-Yan processes. Twist-3 operators are involved in the factorization. We find that the so-called soft-gluon-pole…
Estimates are given for the double spin asymmetry in lepton-pair production from collisions of transversely polarized protons and antiprotons for the kinematics of the recently proposed PAX experiment at GSI on the basis of predictions for…
We study single-spin asymmetries in semi-inclusive deep inelastic scattering with transversely polarized target. Based on the QCD factorization approach, we consider Sivers and Collins contributions to the asymmetries. We fit simple…
We calculate the Drell-Yan cross section, resolving the full kinematics of the lepton pair, at high transverse momentum for hadron nucleus collisions. We use the general framework of Luo, Qiu and Sterman to calculate double scattering…
The gluon transversity distribution in the deuteron is defined by the matrix element between linearly-polarized deuteron states, and it could be investigated in proton-deuteron collisions in addition to lepton-deuteron scattering. The…
We study the single spin asymmetries for the $\pi p^\uparrow\rightarrow\mu^+\mu^-X$ process. We consider the asymmetries contributed by the coupling of the Boer-Mulders function with the transversity distribution and the pretzelosity…
We explore the electromagnetic gauge invariance of the hadron tensor of the Drell-Yan process with one transversely polarized hadron. The special role is played by the contour gauge for gluon fields. The prescription for the gluonic pole in…
We calculate the perturbative $T$-odd contributions to the lepton angular distribution in the Drell-Yan process. Using collinear factorization, we work at the first order in QCD perturbation theory where these contributions appear, ${\cal…
We discuss transversity distributions and transverse spin asymmetries. First, $Q^2$ evolution results are shown for transversity and longitudinally polarized distributions. Second, the antiquark flavor asymmetry $\Delta_{_T} \bar…
We investigate the theoretical framework of the $\cos 2\phi$ azimuthal asymmetry contributed by the coupling of two Boer-Mulders functions in the dilepton production unpolarized $\pi p$ Drell-Yan process by applying the transverse momentum…
We present predictions for the non-singlet Drell-Yan longitudinal spin cross sections and spin asymmetry, $A_{LL}$, in proton-proton collisions at large $p_T$ at the RHIC energy of $200\gev$ at next-to-leading order QCD. The higher order…
Estimates are given for the double spin asymmetry in lepton-pair production from collisions of transversely polarized protons and antiprotons for the kinematics of the recently proposed PAX experiment at GSI on the basis of predictions for…
We discuss transverse double-spin asymmetries for dimuon production at small transverse-momentum $Q_T$ in $pp$ and $p\bar{p}$ collisions. All order resummation of large logarithms relevant in small $Q_T$ region is performed at…
Taking into account the effect of final state interaction, we calculate the non-zero (na\"{i}ve) $T$-odd transverse momentum dependent distribution $h_1^{\perp}(x,\kp^2)$ of the pion in a quark-spectator-antiquark model with effective…