Observation of the Naive-T-Odd Sivers Effect in Deep-Inelastic Scattering

Abstract

Azimuthal single-spin asymmetries of leptoproduced pions and charged kaons were measured on a transversely polarized hydrogen target. Evidence for a naive-T-odd, transverse-momentum-dependent parton distribution function is deduced from nonvanishing Sivers effects for pi(+), pi(0), and K(+/-), as well as in the difference of the pi(+) and pi(-) cross sections.

Longitudinal and transverse spin asymmetries for inclusive jet production at mid-rapidity in polarizedp+pcollisions ats=200 GeVAdamczyk1, Agakishiev2, Aggarwal3 et al. 2012Phys. Rev. DSelf Cite805380View full textAdd to dashboardCite

“…This supports the use of this framework in interpreting our measurements of A LL . Semi-inclusive deep-inelastic scattering experiments have also measured a broad range of transverse spin asymmetries (see for example [31][32][33][34][35][36]), including asymmetries sensitive to the Collins and Sivers effects. The Collins effect involves the convolution of quark transversity with the transverse-spin-dependent Collins fragmentation function, which has been measured in e þ e À scattering [37,38].…”

Relating transverse structure of various parton distributions

“…Recently, there are many theoretical investigations as well as experiments (e.g. ZEUS, COMPASS, HERMES, CLAS [1][2][3][4][5]) to understand the generalized parton distributions(GPDs) and transverse momentum dependent(TMDs) distributions which encode these informations. These objects represent similar albeit non-identical transverse structure and in this paper we are aiming to relate these in a straightforward manner.…”

Imaging the proton

“…the Sivers effect. The Sivers effect has been measured by three different collaborations: HERMES at DESY [30], COMPASS at CERN [31], and Hall A at Jefferson Lab [32]. Several parametrizations have been figured out to extract the x dependence of the Sivers function from these data.…”