Probing the Gluon Sivers Function with an Unpolarized Target: GTMD Distributions and the Odderons

Renaud Boussarie , Yoshitaka Hatta , Lech Szymanowski , Samuel Wallon (1, 2)

1 LPTHE - Laboratoire de Physique Théorique et Hautes Energies
2 UP4 - Université Paris-Sorbonne

It is commonly believed that the Sivers function has uniquely to do with processes involving a transversely polarized nucleon. In this Letter we show that this is not necessarily the case. We demonstrate that exclusive pion production in unpolarized electron-proton scattering in the forward region is a direct probe of the gluon Sivers function due to its connection to the QCD odderon.

Mots clés: Nuclear Physics; electron p: scattering; pi: production; exclusive reaction; Sivers function; polarization: transverse; odderon; quantum chromodynamics; nucleon; gluon

Domaines: Physique des Hautes Energies - Phénoménologie [hep-ph]; Physique des Hautes Energies - Expérience [hep-ex]; Physique Nucléaire Expérimentale [nucl-ex]; Physique Nucléaire Théorique [nucl-th]

Renaud Boussarie, Yoshitaka Hatta, Lech Szymanowski, Samuel Wallon. Probing the Gluon Sivers Function with an Unpolarized Target: GTMD Distributions and the Odderons. Physical Review Letters, 2020, 124 (17), pp.172501. ⟨10.1103/PhysRevLett.124.172501⟩. ⟨hal-02439997⟩