2017/07/31 by U. D’Alesio, Umberto D'Alesio, F. Murgia +2
Physics and Astronomy · #Asymmetry #Deep inelastic scattering #Gluon #Hadron #High-Energy Particle Collisions Research #Inelastic scattering #Jet (fluid) #Nuclear physics #Particle physics #Particle physics theoretical and experimental studies #Parton #Physics #Pion #Quantum Chromodynamics and Particle Interactions #Quantum chromodynamics #Quark #Rapidity #Scattering #Universality (dynamical systems) #hep-ph
paper · pdf · doi:10.1016/j.physletb.2017.08.023
published as Phys.Lett. B773 (2017) 300-306 · 10 pages, 5 figures (10 plots); v2: discussion on jet kT dependence of the SSAs extended and one plot on the corresponding unpolarized cross section added (Fig. 3, right panel); few comments on factorization breaking effects and on the universality issue of the Collins function added; three references added; results unchanged; matches the published version
openalex created_date 2017/07/14 · openalex publication_date 2017/08/25 · arxiv created 2017/10/18 · arxiv updated 2017/10/19 · openalex updated_date 2026/08/05
By adopting a generalised parton model approach at leading order in QCD, including spin and intrinsic parton motion effects, we study the Collins azimuthal asymmetries for pions within a large-pT jet produced at mid-rapidity in polarised hadronic collisions. Using available information on the quark transversity distributions and the pion Collins functions, as extracted from semi-inclusive deeply inelastic scattering and e+e−→h1h2X processes, we compute estimates for the Collins asymmetries in kinematical configurations presently investigated at RHIC by the STAR Collaboration. Collins-like asymmetries, involving linearly polarised gluons, are also considered. Our predictions, compared against available preliminary data, show a very good agreement, even if some discrepancies, to be further scrutinized both theoretically and experimentally, appear in the transverse momentum dependence of the Collins asymmetry. These results are in favour of the predicted universality of the Collins function and of a mild, if any, evolution with the hard scale of the asymmetries.