Azimuthal asymmetries of hadrons produced in muon SIDIS off longitudinally polarized deuterons

Abstract

Abstract. The azimuthal asymmetries in the cross sections of charged-hadron production in the muon SIDIS reactions off the longitudinally polarised deuterons are determined using the COMPASS data of 2006 and combined data of [2002][2003][2004][2005][2006]. The asymmetries are presented as functions of the hadron azimuthal angle ϕ in two ways: first, for hadrons integrated over the kinematic variables and, second, as a function of one of the kinematic variables x, z or p h T while integrating over two other. In each case asymmetries were fitted by functions included the ϕ-independent terms and terms amplitude of which are modulated with ϕ as predicted by the theory: sin ϕ, sin 2ϕ, sin 3ϕ and cos ϕ. Results for amplitudes are presented and discussed.

T-odd proton-helicity asymmetry in semi-inclusive DIS in perturbative QCD

“…Second, measurements of the relevant azimuthal terms have been carried out in various fixedtarget experiments by the HERMES [25][26][27][28], CLAS [29] and COMPASS [30][31][32] collaborations, albeit in kinematic regions that are not clearly in the perturbative regime. Nevertheless, it is interesting to see whether the perturbative calculations give results that are roughly consistent with data at the highest transverse momenta P h⊥ of the produced hadron accessed so far.…”