Abstract
In the field theoretical description of hadronic scattering processes, single transverse-spin asymmetries arise due to gluon initial and final state interactions. These interactions lead to process dependent Wilson lines in the operator definitions of transverse momentum dependent parton distribution functions. In particular for hadron–hadron scattering processes with hadronic final states this has important ramifications for possible factorization formulas in terms of (non)universal TMD parton distribution functions. In this paper we will systematically separate the universality-breaking parts of the TMD parton correlators from the universal T-even and T-odd parts. This might play an important role in future factorization studies for these processes. We also show that such factorization theorems will (amongst others) involve the gluonic pole cross sections, which have previously been shown to describe the hard partonic scattering in weighted spin asymmetries.
Highlights
Many theoretical as well as experimental studies in recent years have been aimed at better understanding the processes that cause spin asymmetries in hadronic scattering
We have argued that the gluonic pole cross sections, the hard partonic scattering functions that are folded with the collinear parton distribution functions in weighted spin-asymmetries, appear in unintegrated, unweighted hadronic cross sections
Assuming as a starting point that the hadronic cross section factorizes at the diagrammatic level in a hard partonic function and for each of the observed hadrons a soft parton correlator, we have shown that the transverse momentum dependent cross section can be written in terms of soft and hard functions that are separately manifestly gauge-invariant
Summary
Many theoretical as well as experimental studies in recent years have been aimed at better understanding the processes that cause spin asymmetries in hadronic scattering. Upon integration over intrinsic transverse momenta all the effects of the complicated gauge link structures in the TMD correlators disappear, while for the transverse moment they contribute a gluonic pole matrix element with multiplicative prefactors, referred to as gluonic pole strengths These are color-fractions that, in principle, differ for each Feynman diagram that contributes to the partonic subprocess. [20,21] a TMD factorization formula based on onegluon radiation was proposed for the quark-Sivers contribution to the SSA in dijet production in proton–proton scattering This result involves the gluonic pole cross sections found in Refs. By using the gluonic pole strengths we will in this paper systematically separate the universality-breaking parts of the TMD parton correlators from the universal T -even and T -odd matrix elements It is a non-trivial observation that this is possible and we believe that it constitutes another important ingredient in trying to relate the results of Refs.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
