Related papers: Sivers and Collins Single Spin Asymmetries
We carry out the first calculation for the twist-3 gluon contribution to the single transverse-spin asymmetry(SSA) in $J/\psi$ production in semi-inclusive deep inelastic scattering. Our result shows that the $J/\psi$ SSA is an ideal…
We analyse the role of partonic transverse motion in unpolarized Semi-Inclusive Deep Inelastic Scattering (SIDIS) processes. Imposing appropriate kinematical conditions, we find some constraints which fix an upper limit to the range of…
We have presented the results for the single and double spin asymmetries in semi-inclusive deep inelastic scatterings for proton in a light front quark-diquark model. The asymmetries generated by the T-even TMDs are discussed here. The…
New data on the Sivers azimuthal asymmetry measured in semi-inclusive deep-inelastic scattering processes have recently been released by the COMPASS Collaboration at CERN. Their increased precision and their particular binning, in terms of…
A complete, fundamental understanding of the proton must include knowledge of the underlying spin structure. The transversity distribution, $h_1\left(x\right)$, which describes the transverse spin structure of quarks inside of a…
Transverse single-spin asymmetries (SSA) in inclusive reactions are now considered to be directly related to the transverse momentum $k_{T}$ of the fundamental partons involved in the process. Several possible leading-twist QCD mechanisms…
In this article we review the present understanding of azimuthal and single spin asymmetries for inclusive and semi-inclusive particle production in unpolarized and polarized hadronic collisions at high energy and moderately large…
We present a global analysis of Sivers functions, transversity distribution functions, and Collins fragmentation functions within the transverse momentum dependent factorization. This analysis encompasses the latest data from semi-inclusive…
We report the first measurements of transverse single-spin asymmetries for inclusive jet and jet + $\pi^{\pm}$ production at midrapidity from transversely polarized proton-proton collisions at $\sqrt{s} = 500$ GeV. The data were collected…
The abundant production of lepton pairs via $J/\Psi$ creation at COMPASS, $\pi ^\pm \, p^\uparrow \to J/\Psi \, X \to \ell^+ \ell^- X$, allows a measurement of the transverse Single Spin Asymmetry generated by the Sivers effect. The crucial…
We illustrate, in a semi-classical picture, how the Wilson line phase factor in gauge invariantly defined unintegrated parton density can lead to a nonzero single-spin asymmetry (Sivers effect).
Some recent analyses of single-spin and azimuthal asymmetries in SIDIS and Drell-Yan processes, focusing in particular on Collins, Sivers and Boer-Mulders effects, are briefly reviewed. The perspectives for future phenomenological studies…
COMPASS is a fixed target experiment presently running at CERN. In 2002, 2003, and 2004 the experiment used a 160 GeV polarized muon beam coming from SPS and scattered off a $^6$LiD target. The nucleons in the target can be polarized either…
Transverse spin physics is an important part of the scientific programme of the COMPASS experiment at CERN. The analysis of the data taken with the target polarized orthogonally to the 160 GeV/c muon beam momentum has allowed to measure for…
We report the first measurement of the opening angle distribution between pairs of jets produced in high-energy collisions of transversely polarized protons. The measurement probes (Sivers) correlations between the transverse spin…
We extend the improved Collins-Soper-Sterman (iCSS) $W+Y$ construction recently presented in~\cite{Collins:2016hqq} to the case of polarized observables, where we focus in particular on the Sivers effect in semi-inclusive deep-inelastic…
Some properties of intrinsic transverse momentum dependent nucleon distribution functions are considered in the simple quark-diquark model. The transverse target polarization dependent asymmetries for SIDIS are calculated and compared with…
In this talk I want to illustrate the many possibilities for studying the structure of hadrons in hard scattering processes by giving a number of examples involving increasing complexity in the demands for particle polarization, particle…
Some general remarks on parton transverse spin distributions and transverse motions are presented. The issue of accessing experimental information on the transversity distributions h_1^q is discussed. In particular direct information could…
In the list of the main items studied by the CERN COMPASS experiment there are the transverse spin and momentum effects visible in the azimuthal distributions of hadrons produced in the deep inelastic scattering. In the years 2002-2004…