Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gluon polarization measurements from longitudinally polarized
  proton-proton collisions at STAR   The gluon polarization contribution to the proton spin is an integral part to
solve the longstanding proton spin puzzle. At the Relativistic Heavy Ion
Collider (RHIC), the STAR experiment has measured jets produced in
mid-pseudo-rapidity, $|\eta| < $ 1.0, and full azimuth, $\phi$, from
longitudinally polarized $pp$ collisions to study the gluon polarization in the
proton. At center of mass energies $\sqrt{s} =$ 200 and 510 GeV, jet production
is dominated by hard QCD scattering processes such as gluon-gluon ($gg$) and
quark-gluon ($qg$), thus making the longitudinal double-spin asymmetry
($A_{LL}$) sensitive to the gluon polarization. Early STAR inclusive jet
$A_{LL}$ results at $\sqrt{s} = $ 200 GeV provided the first evidence of the
non-zero gluon polarization at momentum fraction $x > $ 0.05. The higher center
of mass energy $\sqrt{s} = 510$ GeV allows to explore the gluon polarization as
low as $x \sim$ 0.015. In this talk we will present the recent STAR inclusive
jet and dijet $A_{LL}$ results at $\sqrt{s} = 510$ GeV, and discuss the
relevant new analysis techniques for the estimation of trigger bias and
reconstruction uncertainty, the underlying event correction on the jet energy
and its effect on jet $A_{LL}$. Dijet results are shown for different
topologies in regions of pseudo-rapidity, effectively scanning the
$x$-dependence of the gluon polarization.

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The categories of this paper are: cond-mat
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The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
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The categories of this paper are: physics
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: hep-th
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The categories of this paper are: q-alg
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The categories of this paper are: gr-qc
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The categories of this paper are: nucl-th
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The categories of this paper are: math-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: nlin