Measurement of transverse single-spin asymmetries for dijet production in polarized proton-proton collisions at $\sqrt{\mathbf{s}}$ = 200 $\mathrm{G}\mathrm{e}\mathrm{V}$

We report a new measurement of transverse single-spin asymmetries for dijet production in collisions of polarized protons at $\sqrt{s}$ = 200 $\mathrm{G}\mathrm{e}\mathrm{V}$$\mathrm{.}Correlationsbetweentheprotonspinandthetransversemomentaofitspartons,eachperpendiculartotheprotonmomentumdirection,areprobedathigh$Q^2$ $\approx$160 ${\mathrm{G}\mathrm{e}\mathrm{V}}^2$. Evidence for nonzero Sivers effects is measured for the first time in dijets from proton-proton collisions, but only when the jets are sorted by their net charge, which enhances the otherwise canceling opposite-sign $u$- or $d$-quark contributions to separate data samples. The resulting asymmetries are compared to recent theoretical calculations. Separately, the associated Sivers observable $\text{kt}$, the average parton transverse momentum, is extracted using a simple kinematics approach which further enables a determination of the individual partonic contributions to the observed asymmetries.