First Measurement of the Jet Charge in $\sqrt{s} = 200$ GeV $pp$ Collisions at STAR

The total electrical charge in an isolated system is conserved, so the charge of a parton, i.e. quark or gluon, originating from a high-$Q^{2}$ process within a high-energy proton-proton collision, is conserved throughout the parton shower evolution and hadronization process. Consequently, this should be reflected in the overall charge of a measured jet. In this talk, we present the first measurement of the jet charge at RHIC using data from $\sqrt{s} = 200$ GeV $pp$ collisions at STAR. By performing the measurement differentially in jet transverse momentum, the jet energy dependent fractions of quark- and gluon-initiated jets can be studied. On the other hand, in heavy-ion collisions, hard gluons traversing the quark-gluon plasma are expected to lose more energy via gluon bremsstrahlung than quarks due to the increased color factor. Therefore, this reference measurement can also be used as a baseline for a study of the quark and gluon energy loss in the hot medium.