Twist-4 contributions to the azimuthal asymmetry in semi-inclusive deeply inelastic scattering

Abstract

We calculate the differential cross section for the unpolarized semi-inclusive deeply inelastic scattering (SIDIS) process e − + N → e − + q + X in leading order (LO) of perturbative QCD and up to twist-4 in power corrections and study in particular the azimuthal asymmetry cos 2φ . The final results are expressed in terms of transverse momentum dependent (TMD) parton matrix elements of the target nucleon up to twist-4. We also apply it to e − + A → e − + q + X and illustrate numerically the nuclear dependence of the azimuthal asymmetry cos 2φ by using a Gaussian ansatz for the TMD parton matrix elements.

Leading and higher twist contributions in semi-inclusivee+e−annihilation at high energies

“…The collinear expansion was first applied to deeply inelastic lepton-nucleon scattering (DIS) and provides an unique way to obtain a consistent formalism that relates the gauge invariant parton distribution and/or correlation functions to the measurable quantities such as the differential cross section including leading as well as higher twist contributions. Recently, we have shown that it can be applied to semi-inclusive DIS with nucleon and nucleus targets for jet production [32][33][34][35][36] and corresponding expressions for the azimuthal asymmetries and nuclear dependences have been obtained. Furthermore, we have also successfully applied it to the inclusive hadron production in e + e − annihilation and obtained the corresponding gauge invariant formalism for the hadronic tensor and the differential cross section.…”

“…Recently, the collinear expansion has been applied successfully to semi-inclusive deep inelastic lepton-nucleon scattering process l + N → l + q(jet) + X [32,33], where q denotes a quark that corresponds to a jet in experiments. With this process, TMD parton distribution and/or correlation functions can be studied.…”

“…With this process, TMD parton distribution and/or correlation functions can be studied. Calculations have been carried out where leading and higher twist contributions and also nuclear dependences have been obtained and expressed in terms of the gauge invariant parton distribution and correlation functions [32][33][34][35][36][37].…”

Three Dimensional Imaging of the Nucleon — TMD (Theory and Phenomenology)

“…[25][26][27].For unpolarized e − + N → e − + q(jet) + X, the results up to twist 4 have also been obtained. 24 These results can be used as the basis for measuring these TMDs via the corresponding process at the LO in pQCD. I call in particular the attention to …”

“…14 A proper treatment of such twist-4 effect involves twist-4 TMDs as discussed in Ref. [24]. Because of the multiple gluon scattering shown in Fig.…”