Speaker
Daniel Pitonyak
(RIKEN BNL Research Center)
Description
Transverse single-spin asymmetries (TSSAs), denoted A_N, in single-inclusive hard scattering processes are fundamental observables to test perturbative QCD that have been around for almost 40 years. However, many open issues remain as to the origin of TSSAs. Currently two theoretical formalisms are widely used: collinear twist-3 (CT3) factorization and the Generalized Parton Model (GPM). We discuss our work in this area using the framework of the former, including recent calculations of pion and direct photon production in proton-proton collisions. We also briefly talk about how lepton-nucleon scattering can offer complementary information to that from proton-proton reactions. Given the progress that has been made so far, continued experimental and theoretical work could finally allow us to understand this longstanding problem.
Primary author
Daniel Pitonyak
(RIKEN BNL Research Center)
Co-authors
Andreas Metz
(Temple University)
Koichi Kanazawa
(Temple University)
Yuji Koike
(Niigata University)
