Measurement of transverse single-spin asymmetries for J/ψ production in polarized p + p collisions at √s = 15GeV*

The transverse single-spin asymmetry (TSSA) is a measure of the imbalance in particle production concerning the plane defined by the transverse spin axis and the direction of momentum of a polarized hadron. TSSAs have gained recognition as a method for examining Quantum Chromodynamics (QCD), both within the initial-state hadrons and during the process of hadronization from partons. In J/ψ production, which involves processes with initial-state gluons, TSSAs of J/ψ offer insight into gluon dynamics within the nucleon. The SpinQuest experiment (E1039) at Fermilab employs an unpolarized 120GeV proton beam colliding with a polarized fixed target composed of either NH₃ or ND₃. This experiment aims to derive Sivers functions for the light sea-quarks within the range of 0.1 < xB < 0.5. These measurements are crucial for deducing the gluon Sivers function and provide a unique kinematic coverage, acting as a link between investigating valence quarks and the kinematics studied in future Electron-Ion Collider (EIC) experiments. In this talk, I will discuss the present status of SpinQuest and preliminary results obtained from beam commissioning data.