EMMI Workshop: Light-ion collisions 2026

The sPHENIX detector at RHIC was designed for precision measurements of jets, photons, and heavy flavor to study the quark-gluon plasma (QGP). Its recently completed data-taking campaign includes p+p and O+O collisions at √s_NN = 200 GeV, recording integrated luminosities of 115/pb and 53/nb, respectively. This dataset provides a new opportunity to investigate how QGP signatures depend on system size and how collision geometry and nucleon substructure influence observables in small systems. This talk will present an overview of the sPHENIX O+O program and its underlying physics motivation, including the first measurement from this dataset, the nuclear modification of inclusive jets. Additional analyses are underway, spanning both bulk observables and hard probes. Together, these measurements will provide a broad picture of small-system dynamics at RHIC energies and complement the light-ion program at the LHC by extending these studies to lower collision energies.