Speaker
Prof.
Yuji Koike
(Niigata University)
Description
In this talk, I will present an overview on the current status of the analyses of the
spin asymmetries, in particular, single spin asymmetries, using the framework of
the collinear twist-3 (CT3) factorization.
In this framework, twist-3 quark-gluon or three-gluon correlation functions
in the initial nucleon and the twist-3 fragmentation function for the final hadron
play a critical role as a source of the asymmetries. I will summerize the formalism
and the characteristics features of the analyses. Though this mechanism is designed for the
description of the spin asymmetries in the region of the large transverse momentum P_T
of the final hadron, it also provides the asymmetries at lower P_T
which is consistent with the transverse-momentum-dependent (TMD) factorization.
Some of the functions in the CT3 and TMD factorizations are related to each other
by the QCD equation of motion, which allows us to perform a global analysis of the
spin asymmetries including both low P_T and large P_T data. I will summerized these features
of the CT3 factorization.
Author
Prof.
Yuji Koike
(Niigata University)
