Hard probes created through large momentum transfers are used to study
the properties of QCD matter created in heavy-ion collisions, by
comparing the measurements to those in p+p collisions. Jets, and the
"quenching" or suppression of jets in the medium created in heavy-ion
collisions, are studied through various different observables. We
present the most recent measurements from $\sqrt{s_{NN}}$ = 200 GeV
Au+Au collisions, with p+p collisions as the reference, by the STAR
Collaboration. The observables are semi-inclusive charged
jets and di-jet transverse momentum imbalance. Additionally, correlation
measurements of direct photon-hadron and neutral pion-hadron are
presented and discussed.