Studies of Jet-related Two-Particle Correlations in Small and Peripheral Heavy Ion Systems with PHENIX

The study of high pT 2-particle correlation observables in small systems like $d+Au$ is considered to be useful to isolate cold-nuclear matter effects. Comparison of the correlations in small systems to that in Au+Au can help to identify effects from the final-state interactions in the quark gluon plasma, QGP, created in $Au+Au$. The quantity, $R_I$, the double ratio of near- to away-side per-trigger yields divided by the same in the $p+p$ reference, can cancel out the systematics to the level where very small suppressions or enhancements could be observable. Since these types of signals could be qualitatively similar to energy-loss jet modification due to presence of hot QGP seen in $Au+Au$, we investigate possible cold nuclear effects, systematics, and backgrounds for an existing PHENIX preliminary result for RI in the $d+Au$ system. Also, we present the status and possibilities of making the RI measurement in other small systems, such as $p+Au$, and $^{3}$$He+Au$ and also in peripheral $Au+Au$ for reference.