Koichi Kanazawa

Towards an explanation of transverse single-spin asymmetries in proton-proton collisions: the role of fragmentation in collinear factorization

We study the transverse single-spin asymmetry for single-hadron production in proton-proton collisions within the framework of collinear twist-3 factorization in Quantum Chromodynamics. By taking into account the contribution due to parton fragmentation we obtain a very good description of all high transverse-momentum data for neutral and charged pion production from the Relativistic Heavy Ion Collider. Our study may provide the crucial step towards a final solution to the longstanding problem of what causes transverse single-spin asymmetries in hadronic collisions within Quantum Chromodynamics. We show for the first time that it is possible to simultaneously describe spin/azimuthal asymmetries in proton-proton collisions, semi-inclusive deep-inelastic scattering, and electron-positron annihilation by using collinear twist-3 factorization in the first process along with transverse momentum dependent functions extracted from the latter two reactions.

Twist-2 generalized transverse-momentum dependent parton distributions and the spin/orbital structure of the nucleon

K. Kanazawa, C. Lorcé, A. Metz, B. Pasquini, M. Schlegel 1 Graduate School of Science and Technology, Niigata University, Ikarashi, Niigata 950-2181, Japan Department of Physics, Barton Hall, Temple University, Philadelphia, PA 19122, USA 3 IPNO, Université Paris-Sud, CNRS/IN2P3, 91406 Orsay, France and IFPA, AGO Department, Université de Liège, Sart-Tilman, 4000 Liège, Belgium Dipartimento di Fisica, Università degli Studi di Pavia, and Istituto Nazionale di Fisica Nucleare, Sezione di Pavia, I-27100 Pavia, Italy Institute for Theoretical Physics, Tübingen University, Auf der Morgenstelle 14, D-72076 Tübingen, Germany

New analysis of the single transverse-spin asymmetry for hadron production at RHIC

We analyze the single transverse-spin asymmetry (SSAs) for inclusive hadron production in the pp collision at RHIC based on the twist-3 mechanism in QCD. As an origin of SSAs, we take into account of all kinds of pole contributions associated with the twist-3 quark-gluon correlation functions in the polarized proton. By the inclusion of the soft-fermion-pole contribution in addition to the soft-gluon-pole contribution, we find SSAs observed at RHIC are better described for all kinds of mesons. P{sub T} dependence of the asymmetry and the comparison with the FNAL data are also presented.

A phenomenological study of single transverse-spin asymmetry for inclusive light-hadron productions at RHIC

We study the single transverse-spin asymmetry for inclusive light-hadron productions in the proton-proton collision,

Contribution of the twist-3 fragmentation function to the single transverse-spin asymmetry in semi-inclusive deep inelastic scattering

\pphx

Three-gluon contribution to the single spin asymmetry for light hadron production in pp collision

(

Single transverse-spin asymmetry for direct-photon and single-jet productions at RHIC

h=\pi,K,\eta

Longitudinal-transverse double-spin asymmetries in single-inclusive leptoproduction of hadrons

), for the RHIC kinematics based on the twist-3 mechanism in the collinear factorization. The analysis includes all the contributions from the soft-gluon pole and the soft-fermion pole for the twist-3 quark-gluon correlation functions in the transversely polarized proton. After discussing the flavor decomposition and the

Transverse Single-Spin Asymmetries in Proton-Proton Collisions at the AFTER@LHC Experiment

P_T

Proper definition and evolution of generalized transverse momentum dependent distributions

-dependence of the asymmetry obtained in the previous analysis at the center-of-mass energy