Transverse Spin Dependent Azimuthal Correlations of Charged Pion Pairs in p↑p collisions at √s = 510 GeV at STAR

The transverse polarization of quarks within a transversely polarized nucleon, hq₁(x), can only be accessed through processes involving its coupling with another chiral-odd functions, such as the spin-dependent interference fragmentation function (IFF) in polarized proton-proton collisions. The coupling of hq₁(x) and IFF leads to a measurable azimuthal correlation asymmetry (A_UT^sin(φ_RS)) of di-hadron pairs in the final state. In previous work, the STAR experiment at RHIC measured a non-zero A_UT^sin(φ_RS) using polarized proton-proton (p^↑ p) data from 2011 at √ s = 500 GeV, with an integrated luminosity of 25 pb⁻¹. The precise measurement of A_UT^sin(φ_RS) together with unpolarized di-hadron cross section will help to constrain the hq₁(x) in the global fits. In 2017, the STAR experiment collected dataset of approximately 350 pb⁻¹ from p^↑ p collisions at √ s = 510 GeV. This new dataset will significantly improve the statistical precision of the A_UT^sin(φ_RS) measurement. In this proceedings, we will present preliminary result of the measurement of A_UT^sin(φ_RS) for pion pairs in the pseudorapidity region |η|<1 based on the STAR 2017 p^↑ p dataset.