The complete tree-level result up to order 1/Q for polarized deep-inelastic leptoproduction

Abstract

The complete tree-level result up to order 1/Q for polarized deep-inelastic leptoproduction [Nucl. Phys. B461 (1996) We present the results of the tree-level calculation of deep-inelastic leptoproduction, including polarization of target hadron and produced hadron. We also discuss the dependence on transverse momenta of the quarks, which leads to azimuthal asymmetries for the produced hadrons.

Azimuthal and single spin asymmetries in hard scattering processes

“…[126,108]. For the twist-three case these functions have no partonic interpretation since they are related to quark-quark-gluon matrix elements.…”

“…All functions above depend on x and |k ⊥ |. Few words on the above notation are helpful: f , g and h stand for unpolarized, longitudinally polarized, and transversely polarized quarks, respectively: the subscript "1" stands for leading twist; the apex ⊥ indicates the explicit presence of transverse momenta with a noncontracted index [126]; the subscripts L, T stand for the longitudinal and transverse polarization of the hadron. Therefore, for instance, f 1 is the TMD unpolarized PDF, f ⊥ 1T is the Sivers function and h 1T , h ⊥ 1T are related to the TMD transversity distribution.…”

“…This TMD function, first introduced in Ref. [126], needs not to vanish, and is in a sense the analogue of the Sivers PDF in the fragmentation sector. As it will be discussed in section 5, it can play a relevant role for the description of transverse Λ polarization in unpolarized hadronic collisions within a pQCD approach.…”

Leading-twist single-transverse-spin asymmetries: Drell–Yan and deep-inelastic scattering

“…• Another time-reversal odd parton distribution is permitted [2,7,8]: this is labeled h ⊥ 1 , and it gives a transversity to quarks taken from an unpolarized hadron. (The transversity is dependent on the transverse momentum of the quark.…”

“…(1) can be decomposed [7,8] into the conventional spin-independent term and a spin-dependence s T × k T /M times a special parton density, labeled f ⊥ 1T . Calculations can be readily performed to reproduce the BHS result from the SSA of the parton density defined by Eq, (1).…”