Run12 Inclusive and Dijet Jet A_LL Paper Page


Longitudinal double-spin asymmetry for inclusive jet and dijet production in pp collisions at $\sqrt{s} =$ 510 GeV


Zilong Chang, Renee Fatemi, Carl Gagliardi, Suvarna Ramachandran

GPC members:

Ernst Sichtermann (Chair), Raghav Elayavalli (Member at large), Stephen Trentalange (Member), Dmitry Kalinkin (Member), and Oleg Eyser (PWG rep)

Target Journal:

Physical Review D 


We report the first measurement of the inclusive jet and dijet longitudinal double-spin asymmetry, $A_{LL}$, at midrapidity in polarized $pp$ collisions at a center-of-mass energy, $\sqrt{s} = 510$ GeV. The inclusive jet $A_{LL}$ measurement provides sensitivity to the gluon helicity distribution down to a gluon momentum fraction of $x\approx 0.015$, while the dijet measurements, separated into four jet-pair topologies, provide constraints on the $x$ dependence of the gluon polarization. Both results are consistent with previous measurements made at $\sqrt{s}= 200$ GeV in the overlapping kinematic region, $x > 0.05$, and show good agreement with predictions from recent next-to-leading order global analyses.

STAR publication page:

Paper Proposal Page:

Current paper draft version:

Journal Resubmission, Dated : July 31, 2019

Responses to Referees,  Dated: July 31, 2019
Responses to Referees,  Dated: July 29, 2019
Institutional Responses, Dated : May 20, 2019

Current analysis note versions:

Part I: Inclusive jet ALL (08/12/2018)
Part II:
 Dijet ALL
Part III: Correlation matrix


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Figure 9 upper panel
Figure 9 lower panel
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Figure 14 left panel
Figure 14 right panel

Figure data I
Figure data II

Additional figures:
Correlation matrix


Inclusive jet table file (format is not adjusted to what is in the paper draft)

Analysis code:


Older paper draft versions:

Version 0, Dated: July 23, 2018
Version 1.1Dated: September 24, 2018
Version 1.3Dated: December 17, 2018
Version 1.4,
Dated: February 7, 2019
Version 1.5, Dated : February 27, 2019
Version 2.0, for institutional review, Dated : March 2, 2019
Version 3.0, Dated : May 20, 2019
Version 3.1, Dated : May 26, 2019
Version 3.2, Dated : June 4, 2019

Journal Resubmission, Dated : July 29, 2019

Older analysis note versions:

Inclusive jet ALL (07/30/18)
Dijet ALL