XXVIII International Workshop on Deep Inelastic Scattering and Related Subjects

Measurements of the gluon polarization in the proton from longitudinally polarized pp collisions at STAR at RHIC

24 Mar 2020, 11:20

20m

Brooklyn, NY

Contributed Talk Spin Physics Spin Physics

Speaker

Dmitry Kalinkin (Indiana University / Brookhaven National Laboratory)

Description

Jet production is the primary signal for hard scattering of the partons inside protons, which is one of the dominant processes in proton-proton collisions at the RHIC energies. The jet double-spin asymmetries $A_{\text{LL}}$, measured at the STAR detector in polarized $pp$ collisions, remain one of the main sources of constraint for the polarized gluon parton distribution function $\mathrm{\Delta }g$. An earlier STAR jet measurement at the center of mass energy $\sqrt{s}=200$~GeV provided the first-of-its-kind, clear evidence for the non-zero gluon polarization at $x\ge 0.05$. This talk presents the latest result from the STAR jet measurement at $\sqrt{s}=510$~GeV using a year 2012 data set. The new limit of the kinematic reach down to $x\simeq 0.015$ is achieved by our data at $\sqrt{s}=510$~GeV from both inclusive jets and di-jets. We will also discuss the future opportunities for jet measurements after realisation of an ongoing STAR forward upgrade.