Related papers: Single Spin Asymmetry in Lepton Angular Distributi…
We derive a general framework for describing semi-inclusive deep-inelastic lepton-nucleon scattering in terms of the unintegrated parton distributions and other higher twist parton correlations. Such a framework provides a consistent…
We present predictions of the unweighted and weighted double spin asymmetries related to the transversal helicity distribution $g_{1T}$ and the longitudinal transversity distribution $h_{1L}^\perp$, two of eight leading-twist transverse…
Using the latest quark Sivers functions extracted from the global analysis of available data on single transverse spin asymmetry (SSA), we calculate the SSA of Drell-Yan inclusive production of lepton pairs of invariant mass $Q$ at both…
Using {\sc Sphinx tt}, a new MC simulation program for transverse polarized nucleon--nucleon scattering based on {\sc Pythia~5.6}, we calculate the transverse double spin asymmetry $A^{TT}$ in the Drell-Yan process. If one assumes (quite…
A single-spin asymmetry in the azimuthal distribution of neutral pions relative to the lepton scattering plane has been measured for the first time in deep-inelastic scattering of positrons off longitudinally polarized protons. The…
Nucleon spin structure functions have been investigated mainly by longitudinally-polarized ones for finding the origin of the nucleon spin. Other types of spin structure functions are transversely-polarized ones. In particular, quark…
We describe a new way to access the chiral odd transversity parton distribution in the proton through the photoproduction of lepton pairs. The basic ingredient is the interference of the usual Bethe Heitler or Drell-Yan amplitudes with the…
I report on precision comparisons of theoretical predictions for Drell-Yan (DY) transverse momentum spectra from two approaches: the analytical resummation approach based on Collins-Soper-Sterman (CSS) formalism and the parton branching…
We check numerically if Soffer's inequality for quark distributions is preserved by next-to-leading order QCD evolution. Assuming that the inequality is saturated at a low hadronic scale we estimate the maximal transverse double spin…
Single spin asymmetries in polarized proton(antiproton) + proton -> pion + X have been measured to be large. They can be understood within perturbative QCD by introducing new k_perp and spin dependences in fragmentation and/or distribution…
We show that for Drell-Yan events by unpolarized hadronic projectiles and nuclear targets, azimuthal asymmetries can arise from the nuclear distortion of the hadronic projectile wave function, typically a spin-orbit effect occurring on the…
We consider the various asymmetries, notably single spin asymmetries, that appear in leptoproduction as a consequence of the presence of time-reversal odd distribution functions. This could facilitate experimental searches for time-reversal…
During the INT-18-3 workshop, we presented an analysis of unpolarized Drell-Yan pair production in pion-nucleus scattering with a particular focus into the pion Transverse Momentum Distributions in view of the future Electron Ion Collider.…
We show that initial-state interactions contribute to the $\cos 2 \phi$ distribution in unpolarized Drell-Yan lepton pair production $p p$ and $ p \bar p \to \ell^+ \ell^- X$, without suppression. The asymmetry is expressed as a product of…
We report recent theoretical progress on a polarization asymmetry in the proton-deuteron Drell-Yan process with a polarized-deuteron target and the tensor-polarized structure function $b_1$. Experimental measurements are possible at JLab…
We investigate Drell-Yan pair production in a QCD inspired model, which takes into account all relevant hard processes up to $O(\alpha_s)$. To address the known shortfalls of such a fixed order calculation we introduce phenomenological…
We discuss the double-spin asymmetry \aqt in the transversely polarized Drell-Yan process at small transverse-momentum Q_T of the produced dilepton. The soft gluon corrections relevant for small Q_T are resummed to all orders in \alpha_s,…
The COMPASS experiment at CERN is one of the leading experiments studying the nucleon spin structure. Until 2012 the Parton Distribution Functions and the Transverse Momentum Dependent Parton Distribution Functions (TMDs) were extensively…
We analyze the transverse momentum dependent distribution and fragmentation functions in space-like and time-like hard processes involving at least two hadrons, in particular 1-particle inclusive leptoproduction, the Drell-Yan process and…
We map the distribution of unpolarized quarks inside a unpolarized pion as a function of the quark's transverse momentum, encoded in unpolarized Transverse Momentum Distributions (TMDs). We extract the pion TMDs from available data of…