New mechanism for generating a single transverse spin asymmetry

作者：Kovchegov Yuri V^*; Sievert Matthew D

来源：Physical Review D - Particles, Fields, Gravitation and Cosmology, 2012, 86(3): 034028.

DOI：10.1103/PhysRevD.86.034028

We propose a new mechanism for generating a single transverse spin asymmetry (STSA) in polarized proton-proton and proton-nucleus collisions in the high-energy scattering approximation. In this framework the STSA originates from the q -> qG splitting in the projectile (proton) light-cone wave function followed by a perturbative (C-odd) odderon interaction, together with a C-even interaction, between the projectile and the target. We show that some aspects of the obtained expression for the STSA of the produced quarks are in qualitative agreement with experiment: STSA decreases with decreasing projectile x(F) and is a nonmonotonic function of the transverse momentum k(T). In our framework the STSA peaks at k(T) near the saturation scale Q(s). Our mechanism predicts that the quark STSA in proton-nucleus collisions should be much smaller than in proton-proton collisions. We also observe that in our formalism the STSA for prompt photons is zero.

• 出版日期2012-8-29