Azimuthal Transverse Single-Spin Asymmetries of Charged Pions Within Jets from Polarized $pp$ Collisions at $\sqrt{s}$ = 200 GeV

Understanding the internal spin structure of the nucleon remains an open question in strong interaction physics. Transversity, which describes the transverse spin structure of quarks in a transversely polarized proton, is still quite unconstrained in global analyses. It can be accessed through channels that couple to another chiral-odd distribution like the Collins fragmentation function or the interference fragmentation function. STAR reported the first measurements of Collins asymmetries from jet + $\pi^{\pm}$ production in polarized proton+proton collisions at $\sqrt{s}$ = 500 GeV and 200 GeV based on the data taken during the years 2011 and 2012. These results probe higher momentum scales ($Q^{2}$ $\sim$ 960 $\mathrm{GeV^{2}}$ for 500 GeV and $\sim$ 170 $\mathrm{GeV^{2}}$ for 200 GeV) than the measurements from semi-inclusive deep inelastic scattering (SIDIS, $Q^{2}$ $<$ 20 $\mathrm{GeV^{2}}$) and enable the test of the evolution, universality and factorization breaking in the transverse momentum dependent (TMD) formalisms. Status of the measurement of Collins asymmetry from 2015 proton+proton collisions at $\sqrt{s}$ = 200 GeV with much higher statistics will be presented.