A complete, fundamental understanding of the proton must include knowledge of the underlying

spin structure. The transversity distribution (h_1 (x)), which describes the transverse spin structure

of quarks inside of a transversely polarized proton, is only accessible through channels that couple

h_1 (x) to another chiral odd distribution, such as the Collins fragmentation function (∆D (z, j_T )).

Significant Collins asymmetries of charged pions have been observed in semi-inclusive deep inelastic

scattering (SIDIS) data. These SIDIS asymmetries combined with e^+ e^- process asymmetries from

Belle have allowed for the extraction of h_1 (x) and ∆D (z, j_T ). The current uncertainties on h_1 (x)

are large compared to the corresponding quark momentum and helicity distributions and reflect

the limited statistics and kinematic reach of the available data. In transversely polarized hadronic

collisions, Collins asymmetries may be isolated and extracted by measuring the spin dependent

azimuthal distributions of charged pions in jets. An exploratory STAR analysis with the 2006

s = 200 GeV dataset hinted at a charge dependent Collins asymmetry and motivated a dedicated

transversely polarized proton run in 2012 where an order of magnitude more data was collected (20 pb^{−1})

at an average polarization of 63%. This measurement, coupled with the same measurement

at √s=510 GeV and interference fragmentation function (IFF) measurements at √s = 200 and

500 GeV at midrapidity (|η| < 1) access higher momentum scales than the existing SIDIS data,

and will allow for a comprehensive study of evolution and factorization of the Collins channel.

Preliminary results from the √s = 200 and 500 GeV Collins and IFF analyses will be presented.