Related papers: On the Relation Between Mechanisms for Single-Tran…
Single-spin asymmetry appears due to the interference of single and double gluon exchange between protons. A heavy fermion model is used to describe the jet production in the interaction of gluon with the proton implying the further…
A consistent phenomenological approach to the computation of transverse single spin asymmetries in inclusive hadron production is presented, based on the assumed generalization of the QCD factorization theorem to the case in which quark…
We report progresses on leading-twist transverse-momentum-dependent (TMD) gluon distributions, calculated in a spectator-model framework for the parent nucleon. We encode in our formalism a fit-based parameterization for the spectator-mass…
We reexamine the scale dependence of the gluonic pole tri-gluon correlations relevant for the transverse single spin asymmetries. Our results differ from those of all previous similar calculations. The corresponding asymptotic behavior of…
The longitudinal double spin asymmetry A_LL in the reaction pp --> pi X has been measured at RHIC with extremely interesting consequences. If the gluon polarization in a proton were as big as needed to resolve the famous "spin crisis" then…
We present preliminary results on the leading-twist transverse-momentum-dependent (TMD) gluon linearity function, which is directly connected to nucleon transverse-spin asymmetries originating from the density of linearly-polarized gluons.…
The investigation of transverse spin and transverse momentum effects in deep inelastic scattering is one of the key physics programs of the COMPASS collaboration. In the years 2002-2004 COMPASS took data scattering 160 GeV muons on a…
It is shown that the azimuthal dependence of the distribution of hadrons in a quark jet is a probe of the transverse spin of the quark initiating the jet. This results in a new spin-dependent fragmentation function that acts at the twist-2…
Transverse single-spin asymmetries in the semi-inclusive deep-inelastic production of isolated photons ($\gamma$SIDIS), $A_{UT}^{\gamma {\rm SIDIS}}$, provide an unprecedented opportunity to extract the quark-gluon-quark correlators…
We study the beam single spin asymmetry in semi-inclusive hadron production in deep inelastic scattering in at order 1/Q. There are two competing contributions: the leading order transverse momentum dependent parton distribution…
This is a review of what is currently known about the gluon Sivers distribution and of what are the opportunities to learn more about it. Because single transverse spin asymmetries in $p^\uparrow \, p \to \pi \, X$ provide only indirect…
A single-spin asymmetry was measured in the azimuthal distribution of pi+pi- pairs produced in semi-inclusive deep-inelastic scattering on a transversely polarized hydrogen target. For the first time, evidence is found for a correlation…
Single-spin asymmetries in the semi-inclusive production of charged pions in deep-inelastic scattering from transversely and longitudinally polarized proton targets are combined to evaluate the subleading-twist contribution to the…
The high energy and large p_T inclusive polarized process, (A, S_A) + (B, S_B) --> C + X, is considered under the assumption of a generalized QCD factorization scheme. For the first time all transverse motions, of partons in hadrons and of…
The fragmentation of an unpolarized quark into a transversely polarized spin-1/2 particle is studied in the framework of a simple model. Special attention is payed to the gluon exchange which is incorporated in the gauge link of the…
We present a measurement of the longitudinal spin cross section asymmetry for deep inelastic muon-nucleon interactions with two high transverse momentum hadrons in the final state. Two methods of event classification are used to increase…
Within the theoretical framework we apply, a suggested origin for single spin asymmetries is the presence of gauge links in transverse momentum dependent distribution functions. Recently we found new gauge link structures in a number of…
We study the single transverse-spin asymmetry for open charm production in the semi-inclusive lepton-hadron deep inelastic scattering (SIDIS) and $pp$ collision. Within collinear factorization approach, we find that the asymmetry is…
We present the first calculation of the Efremov-Teryaev-Qiu-Sterman functions and associated twist-3 quark-gluon correlation functions for both the proton and pion. These functions are determined using the light-front wave functions…
We shortly review the various methods suggested for determining the transversity function. Among such methods, we consider especially those based on semi-inclusive deep inelastic scattering. In the framework of this kind of reactions, we…