Transverse Single-Spin Asymmetries in Single-Inclusive Pion Production from Lepton-Nucleon Collisions with Unpolarized Next-to-Leading Order Corrections*

At high energies, collisions between transversely polarized nucleons and leptons can result in a left-right asymmetric production of hadrons referred to as a transverse single-spin asymmetry A_N. This is the focus of our study.  While leading order (LO) predictions have been produced before, these did not provide a solid enough description of the measurements, like those from HERMES. To attempt to improve these calculations, we aim to include next-to-leading order (NLO) corrections for the unpolarized cross section in the denominator of the asymmetry.  These results can then be compared with datasets to determine, in the absence of a full analytical calculation, empirically how large the NLO contributions in the transversely polarized cross section in the numerator of A_N are expected to/must be. We use recent phenomenological extractions of quark-gluon-quark contributions from Sivers-like and Collins-like functions in our analysis to compute A_N and compare to data from HERMES as well as provide predictions for JLab-12, COMPASS, and the future Electron-Ion Collider (EIC).