Investigating Nucleon Structure and Hadronization with Hadrons in Jets at STAR

The STAR collaboration at RHIC provides insight into the spin structure of the nucleon through collisions of longitudinally and transversely polarized beams of protons. Spin-dependent azimuthal distributions of hadrons within jets from transversely polarized proton collisions provide access to the transversity distribution function at a range of $x$ complementary to semi-inclusive deep inelastic scattering (SIDIS) experiments but at a much higher range of $Q^2$. Asymmetries from STAR data collected in 2011 at $\sqrt{s}=500$ GeV and in 2012 at $200$ GeV give the first experimental hints that the universality of this ``Collins mechanism'' may extend to proton-proton collisions, as it does in SIDIS and $e^{+}e^{-}$. The STAR data also provide unique insight to the in-jet transverse momentum dependence of the Collins asymmetry, crucial for a deeper understanding of the Collins fragmentation function. The final 2011 and preliminary 2012 STAR hadron-in-jet data will be presented and discussed in context with recent global transversity analyses and model calculations.