Single-spin asymmetry from pomeron-odderon interference
Abstract
Description
The transverse single-spin asymmetry A_N observed in high energy proton-proton collisions p^\uparrow p \to pi X has been found to increase with the momentum fraction x_F of the pion up to the largest measured x_F \sim 0.8, where A_N \simeq 40%. We consider the possibility that the asymmetry is due to a non-perturbatively generated spin-flip coupling in soft rescattering on the target proton. We demonstrate using perturbation theory that a non-vanishing asymmetry can be generated through interference between exchanges of even and odd charge conjugation provided both helicity flip and non-flip couplings contribute. Pomeron and odderon exchange can thus explain the energy independence of the asymmetry and predicts that the asymmetry should persist in events with large rapidity gaps.
6 pages, 4 figures. Talk at the "Advanced studies institute on symmetries and spin", Prague, July 19-26. v2: Added references
6 pages, 4 figures. Talk at the "Advanced studies institute on symmetries and spin", Prague, July 19-26. v2: Added references