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Volume 352 - XXVII International Workshop on Deep-Inelastic Scattering and Related Subjects (DIS2019) - Working Group 6: Spin and 3D Structure
Constraining the Polarized Gluon Distribution Function of the Proton with Recent STAR Measurements
N. Lukow* on behalf of the STAR collaboration
*corresponding author
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Pre-published on: 2019 July 03
Published on: 2019 October 04
The contribution of the gluon helicity to the spin of the proton is being studied through the use of the unique capability of the Relativistic Heavy Ion Collider (RHIC) to collide polarized protons at $\sqrt{s}=200\,$GeV and $\sqrt{s}=510\,$GeV. The kinematic coverage of the Solenoidal Tracker At RHIC (STAR) allows access to gluons through quark-gluon and gluon-gluon scattering processes which dominate jet production at low and medium transverse momentum. The polarized gluon distribution function, $\Delta g(x)$, can be constrained through a global analysis by measuring the longitudinal double-spin asymmetry ($A_{LL}$) of inclusive jet and di-jet production.

\noindent Published inclusive jet results from 2009 at mid-rapidity ($|\eta| < 1$ ) at $\sqrt{s}=200\,$GeV have been used in global analyses and suggest a statistically significant non-zero truncated first moment of $\Delta g(x)$ for $x>0.05$. An additional data sample of $43\,$pb$^{-1}$ has been collected in 2015. This new data sample is 115\% larger than the previous sample and will improve the precision of $\Delta g(x)$ for $x>0.05$. The status of this new inclusive jet analysis will be presented along with the status of di-jet measurements and previous measurements at $\sqrt{s} = 510\,$GeV which will further constrain $\Delta g(x)$ at lower $x$.
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