Collins Function and the Single Transverse Spin Asymmetry

Collins Fragmentation and the Single Transverse Spin Asymmetry

Single Transverse - Spin Asymmetry in pp ↑ → πX and ep ↑ → πX

where the functions Ga(x1, x2), Eb(x ′ 1, x ′ 2) and Êc(z1, z2) are the twist-3 quantities representing, respectively, the transversely polarized distribution, the unpolarized distribution, and the fragmentation function for the pion. δqa(x) is the transversity distribution in p↑. a, b and c stand for the parton’s species, sum over which is implied. δqa, Eb and Êc are chiral-odd. Corresponding ...

Single transverse-spin asymmetry in Drell-Yan lepton angular distribution

We calculate a single transverse-spin asymmetry for the Drell-Yan lepton-pair’s angular distribution in perturbative QCD. At leading order in the strong coupling constant, the asymmetry is expressed in terms of a twist-3 quark-gluon correlation function T (V ) F (x1, x2). In our calculation, the same result was obtained in both light-cone and covariant gauge in QCD, while keeping explicit elect...

Single spin asymmetry in inclusive pion production, Collins effect and the string model

We calculate the single spin asymmetry in the inclusive pion production in protonproton collisions. We generate the asymmetry at the level of fragmentation function (Collins effect) by the Lund coloured string mechanism. We compare our results with the Fermilab E704 data from p↑p collisions at 200 GeV. We show that the transversely polarized quark densities at high Bjorken x strongly differ fro...

Single Transverse-Spin Asymmetry in Drell-Yan Production at Large and Moderate Transverse Momentum

We study the single-transverse spin asymmetry for the Drell-Yan process. We consider production of the lepton pair at large transverse momentum, q⊥ ∼ Q, where Q is the pair’s mass. The spin asymmetry is then of higher twist and may be generated by twist-three quark-gluon correlation functions. Expanding the result for q⊥ ≪ Q, we make contact with the transversemomentum-dependent QCD factorizati...