The transversity distribution, which describes transversely polarized quarks in a transversely polarized nucleon, is a fundamental component of the current picture of the spin structure of the nucleon, and is only loosely constrained by existing semi-inclusive deep inelastic scattering data. The di-hadron interference fragmentation function (IFF), which describes the fragmentation of transversely polarized quarks, is expected to give rise to spin-dependent di-hadron correlations in p[Formula: see text]+p collisions. Significant di-hadron correlations have recently been measured at RHIC in p[Formula: see text]+p collisions at [Formula: see text] = 200 GeV at mid-rapidity. In 2011, STAR collected p[Formula: see text]+p data at [Formula: see text] = 500 GeV, allowing STAR to extend these di-hadron asymmetries into a previously unexplored kinematic region. The status of the charge-ordered pion pair asymmetry measurement from [Formula: see text] = 500 GeV p[Formula: see text]+p collisions will be presented.
Resonance-like coherent production of a pion pair in the reaction $pd \rightarrow pd \pi\pi$pd→pdππ in the GeV region
