N ov 2 00 2 Single Transverse - Spin Asymmetry in pp ↑ → πX and ep ↑ → πX

40 0 v 1 2 6 N ov 2 00 2 1 Single Transverse Spin Asymmetry in p ↑ p → πX and ep ↑ → πX

ar X iv : h ep - p h / 02 11 19 8 v 1 1 3 N ov 2 00 2 Sivers effect and transverse single spin asymmetries in Drell - Yan processes ∗

Sivers asymmetry, adopted to explain transverse single spin asymmetries (SSA) observed in inclusive pion production, p↑ p → πX and p̄↑ p → πX, is used here to compute SSA in Drell-Yan processes; in this case, by considering the differential cross section in the lepton-pair invariant mass, rapidity and transverse momentum, other mechanisms which may originate SSA cannot contribute. Estimates for ...

Predictions for single spin asymmetries in ℓp ↑ → πX and γ ∗ p ↑ → πX

Predictions for the single transverse spin asymmetry AN in semi-inclusive DIS processes are given; non negligible values of AN may arise from spin effects in the fragmentation of a polarized quark into a final hadron with a transverse momentum k⊥ with respect to the jet axis, the so-called Collins effect. The elementary single spin asymmetry of the fragmenting quark has been fixed in a previous...

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 ...

ar X iv : h ep - p h / 99 05 49 0 v 1 2 6 M ay 1 99 9 1 Single transverse spin asymmetries in inclusive hadron production

A consistent phenomenological approach to the computation of transverse single spin asymmetries in inclusive hadron production is presented, based on the assumed generalization of the QCD factorization theorem to the case in which quark intrinsic motion is taken into account. New k⊥ and spin dependent quark distribution and fragmentation functions are considered: some of them are fixed by fitti...