Related papers: Update on transversity and Collins functions from …
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…
In semi-inclusive DIS of polarized leptons on a transversely polarized target eight azimuthal modulations appear in the cross-section. Within QCD parton model four azimuthal asymmetries can be interpreted at leading order, two of them being…
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 production of vector mesons in SIDIS is a particularly interesting channel to study the polarized fragmentation and related phenomena. Preliminary COMPASS results for the first measurement of inclusive $\rho^0$ Collins and Sivers…
We present an updated study of the Collins azimuthal asymmetries for pion-in-jet production in polarized $pp$ collisions. To this aim, we employ a recent extraction of the transversity and Collins fragmentation functions from semi-inclusive…
We study the Sivers effect in transverse single spin asymmetries (SSA) for pion and kaon production in Semi-Inclusive Deep Inelastic Scattering (SIDIS) processes. We perform a fit of A^{sin(phi_h-phi_S)}_UT taking into account the recent…
By adopting a generalised parton model approach at leading order in QCD, including spin and intrinsic parton motion effects, we study the Collins azimuthal asymmetries for pions within a large-$p_T$ jet produced at mid-rapidity in polarised…
The Collins effect connects transverse quark spin with a measurable azimuthal asymmetry in the yield of hadronic fragments around the quark's momentum vector. Using two different reconstruction methods we measure statistically significant…
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…
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 present preliminary results for an updated extraction of the transversity parton distribution based on the analysis of pion-pair production in deep-inelastic scattering off transversely polarized targets in collinear factorization. Data…
Azimuthal correlations in two hadron production in deep inelastic scattering of unpolarized leptons off transversely polarized nucleon are discussed. Specifically, a simple approach for accessing ratios of structure functions corresponding…
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…
We perform global fit to the quark Sivers function within the transverse momentum dependent (TMD) factorization formalism in QCD. We simultaneously fit Sivers asymmetry data from Semi-Inclusive Deep Inelastic Scattering (SIDIS) at COMPASS,…
Azimuthal asymmetries measured in unpolarized semi-inclusive deep inelastic scattering bring important information on the inner structure of the nucleons, and can be used both to estimate the average quark transverse momentum k_T and to…
Predictions are made for azimuthal asymmetries in pion and kaon production from SIDIS off a longitudinally polarized deuterium target for HERMES kinematics, based on information on the 'Collins fragmentation function' from DELPHI data and…
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…
We study the Collins mechanism for the single transverse spin asymmetry in the collinear factorization approach. The correspondent twist-three fragmentation function is identified. We show that the Collins function calculated in this…
Since 2005, measurements of Collins and Sivers asymmetries from the HERMES and COMPASS experiments have allowed to assess that the transversity and the Sivers PDFs are different from zero and measurable in semi-inclusive DIS on transversely…
Understanding the internal spin structure of the nucleon still remains a challenge in strong interaction physics. Transversity, which describes the transverse spin structure of quarks in a transversely polarized proton, is poorly…