Prospects of polarized fixed target Drell-Yan experiments

TL;DR

This paper discusses the potential of polarized fixed target Drell-Yan experiments to test the predicted sign change of Sivers functions, offering insights into transverse spin phenomena and QCD validation.

Contribution

It evaluates the prospects and physics sensitivities of upcoming polarized Drell-Yan experiments at Fermilab and RHIC, highlighting their potential to test fundamental QCD predictions.

Findings

Potential to confirm or refute Sivers function sign change

Ability to map quark and antiquark Sivers distributions

Critical measurements over a wide kinematic range

Abstract

It has been proposed that the Siverse transverse single spin asymmetry in Drell-Yan production in transversely polarized p+p collisions would have an opposite sign compared to what has been observed in the polarized Semi-Inclusive Deep Inelastic Scattering (SIDIS) experiments. Experimental confirmation or disproval of this prediction would provide a new fundamental test of QCD and shed new light on our theoretical understanding of the transverse spin physics phenomena. We discuss the prospects and physics sensitivities of polarized fixed target Drell-Yan experiments that could utilize the existing proton and other hadron beams at Fermilab, and polarized proton beams at RHIC with a polarized solid proton and/or neutron target option. We show that if realized, the new experiments would provide critical measurements of not only the sign change (or not) of Sivers functions, but also the information of quark and antiquark's Sivers distributions over a wide kinematic range.