Analysis of the double-spin asymmetryALTin inelastic nucleon-nucleon collisions

Abstract

Within the collinear twist-3 framework, we analyze the double-spin asymmetry in collisions between longitudinally polarized nucleons and transversely polarized nucleons with focus on hadron and jet production. As was the case in direct photon production, the double-spin dependent cross section for hadron and jet production has the advantage of involving a complete set of collinear twist-3 functions for a transversely polarized nucleon. In addition, we outline further benefits of this observable for a potential future measurement at RHIC, which includes insight on the gluon helicity distribution as well as information on the Efremov-Teryaev-Qiu-Sterman function T F (x, x) that plays a crucial role in single-spin asymmetries.

Twist-three relations of gluonic correlators for the transversely polarized nucleon

“…The result of this is a set of exact identities which relate G 3T to a certain integral of three-gluon light-cone correlation functions. Not only do these three-gluon correlators emerge in the QCD evolution of g T (x) and the quark-gluon correlators [4,[11][12][13][14], but already at leading order they contribute to SSAs in pion (light hadron) production, jet production, Drell-Yan and direct photon production [9,15] at high P T , and also to A LT with various high-P T final states [16]. As a matter of fact, there is a priori no fundamental argument that the three-gluon contribution is negligible compared to the quark-gluon contribution in these processes.…”

Double spin asymmetries of inclusive hadron electroproduction from a transversely polarizedHe3target

“…Furthermore, it has been proposed that g(x) and quark-gluon-quark correlations are responsible for DSAs of inclusive jet (or hadron) production in polarized nucleon-nucleon reactions and lepton-nucleon reactions in [7,8].…”

Operator constraints for twist-3 functions and Lorentz invariance properties of twist-3 observables

“…Much theoretical work has been performed over the years to develop the collinear twist-3 formalism needed to describe these proton-proton SSAs [14][15][16][17][19][20][21][22][23][24][25][26][27][28][29][30][31] and DSAs [32][33][34][35][36][37][38], including recent extensions to include fragmentation effects [26,27,29,30,38] and tri-gluon correlations [31,37,[39][40][41][42]. Nevertheless, whether this framework can provide a * tuf29138@temple.edu † koike@phys.sc.niigata-u.ac.jp ‡ metza@temple.edu § dpitonyak@quark.phy.bnl.gov ¶ marc.schlegel@uni-tuebingen.de definitive explanation of these observables (especially SSAs) remains an open question.…”