Speaker
Prof.
Kazuhiro Tanaka
(Dept. of Physics, Juntendo University)
Description
It is known that a dominant QCD mechanism for the single transverse-spin
asymmetry in hard processes is induced by the twist-3 quark-gluon correlations
inside a hadron, combined with the soft-gluonic poles to produce the
interfering phase for the associated partonic hard scattering. We show that
the coupling of the relevant soft gluon to partonic subprocess can be
systematically disentangled, so that the corresponding interfering amplitude
can be calculated entirely in terms of the partonic cross section for 2-to-2
Born subprocess which participates in the twist-2 cross section formula. We
establish a new formula that represents the exact rules to derive the SSA due
to soft-gluon poles from the knowledge of the twist-2 cross section formula.
This master formula is applicable to a range of processes like Drell-Yan and
direct-photon production, and pion production in semi-inclusive deep inelastic
scattering and in pp collisions. The detail is reported in our recent paper
HEP-PH 0612117.
Author
Prof.
Kazuhiro Tanaka
(Dept. of Physics, Juntendo University)
Co-author
Prof.
Yuji Koike
(Department of Physics, Niigata University)
