The role of three-gluon correlation functions in the single spin asymmetry

¹ Graduate School of Science and Technology, Niigata University, Ikarashi, Niigata 950-2181, Japan
² Department of Physics, Barton Hall, Temple University, Philadelphia, Pennsylvania 19122, USA
³ Department of Physics, Niigata University, Ikarashi, Niigata 950-2181, Japan
⁴ Theoretical Research Division, Nishina Center, RIKEN, Wako 351-0198, Japan
⁵ Physics Department, Brookhaven National Laboratory, Upton, NY 11973, USA

^a e-mail: beppu@nt.sc.niigata-u.ac.jp
^b e-mail: koichi.kanazawa@temple.edu
^c e-mail: koike@nt.sc.niigata-u.ac.jp
^d e-mail: shinsuke.yoshida@riken.jp

Published online: 23 January 2015

Abstract

We study the twist-3 three-gluon contribution to the single spin asymmetry in the light-hadron production in pp collision in the framework of the collinear factorization. We derive the corresponding cross section formula in the leading order with respect to the QCD coupling constant. We also present a numerical calculation of the asymmetry at the RHIC energy, using a model for the three-gluon correlation functions suggested by the asymmetry for the D-meson production at RHIC. We found that the asymmetries for the light-hadron and the jet productions are very useful to constrain the magnitude and form of the correlation functions. Since the three-gluon correlation functions shift the asymmetry for all kinds of hadrons in the same direction, it is unlikely that they become a main source of the asymmetry.