相关论文: Transversity
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…
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…
A review is given on single spin asymmetries in deep inelastic semi-inclusive scattering (SIDIS) and their possible theoretical understanding in the framework of QCD-induced factorization approach, wherefore predictions for transversity…
Information on the Sivers distribution and the Collins fragmentation functions and their transverse momentum dependence is mainly based on fitting single spin asymmetry data from semi-inclusive deep inelastic scattering (SIDIS). Independent…
It is studied the possibility of direct extraction of the transversity and its accompanying T-odd parton distribution function (PDF) from Drell-Yan (DY) processes with unpolarized pion beam and with both unpolarized and transversely…
In semi-inclusive deep inelastic scattering of polarized leptons on a transversely polarized target eight target transverse spin-dependent azimuthal modulations are allowed. In the QCD parton model half of these asymmetries can be…
We consider the leading twist $T$-odd contributions as the dominant source of the azimuthal and transverse single spin asymmetries in SIDIS and dilepton production in Drell-Yan Scattering. These asymmetries contain information on the…
Single-spin asymmetries in semi-inclusive pion production are measured by the HERMES experiment for the first time, with a transversely polarised hydrogen target. Two different sine-dependencies are extracted which can be related to the…
HERMES has measured azimuthal single-spin asymmetries of charged pions produced in deep-inelastic scattering of positrons on a transversely polarised hydrogen target. The presented azimuthal moments provide access to two yet unknown quark…
We discuss transverse polarization distribution and fragmentation functions, in particular, T-odd functions with transverse momentum dependence, which might be relevant for the description of single transverse spin asymmetries. The role of…
We give a brief overview on some of the latest results on the transversity function. We focus on some recent extractions from azimuthal asymmetries data measured in semi-inclusive deep-inelastic scattering processes, and on the impact of…
A short review of problems with parton distribution functions in nucleons, non-polarized and polarized, is given. The main part is devoted to the transversity distribution its possible measurement and its first experimental probe via spin…
We report the results of a quark model calculation of the transverse polarization distribution $h_1$. Predictions for the Drell-Yan double spin transverse asymmetry are also presented.
A new, preliminary global analysis of the experimental data on azimuthal asymmetries in SIDIS from HERMES and COMPASS collaborations, and in e+e- --> h_1 h_2 X processes from the BELLE collaboration, is performed. The new data allow for a…
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…
The Sivers parton distribution has been predicted to obey a particular ``universality relation'', namely to have opposite sign in semi-inclusive deeply inelastic scattering (SIDIS) and the Drell-Yan process. We discuss how, on the basis of…
Sivers asymmetry, adopted to explain transverse single spin asymmetries (SSA) observed in inclusive pion production, p(transv. polarized) p --> pion + X and p-bar(transv. polarized) p --> pion + X is used here to compute SSA in Drell-Yan…
The most recent data on the weighted transverse single spin asymmetry A_{UT}^{\sin(\phi_h-\phi_S)} from HERMES and COMPASS collaborations are analysed within LO parton model; all transverse motions are taken into account. Extraction of the…
The most recent data on the weighted transverse single spin asymmetry $A_{UT}^{\sin(\phi_h-\phi_S)}$ from HERMES and COMPASS collaborations are analysed within LO parton model with unintegrated parton distribution and fragmentation…
We discuss our present understanding of the transverse spin structure of the nucleon and of related properties originating from parton transverse motion. Starting from the transversity distribution and the ways to access it, we then address…