Measurements of double-helicity asymmetries in inclusive J/ψ production in longitudinally polarized p+p collisions at √s = 510 GeV

Scientific paper - Original scientific paper

• Author: A. Adare
• Author: ...
• Author: Mihael Makek; MBZ: 256122
• Author: ...
• Author: L. Zou
• Collaboration: PHENIX Collaboration
• Author's institution: University of Zagreb; Faculty of Science; (Department of Physics)
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics

Abstract (english)

We report the double-helicity asymmetry, ALLJ/ψ, in inclusive J/ψ production at forward rapidity as a function of transverse momentum pT and rapidity |y|. The data analyzed were taken during s=510 GeV longitudinally polarized p+p collisions at the Relativistic Heavy Ion Collider in the 2013 run using the PHENIX detector. At this collision energy, J/ψ particles are predominantly produced through gluon-gluon scatterings, thus ALLJ/ψ is sensitive to the gluon polarization inside the proton. We measured ALLJ/ψ by detecting the decay daughter muon pairs μ+μ- within the PHENIX muon spectrometers in the rapidity range 1.2<|y|<2.2. In this kinematic range, we measured the ALLJ/ψ to be 0.012±0.010 (stat) ±0.003 (syst). The ALLJ/ψ can be expressed to be proportional to the product of the gluon polarization distributions at two distinct ranges of Bjorken x: one at moderate range x≈5×10-2 where recent data of jet and π0 double helicity spin asymmetries have shown evidence for significant gluon polarization, and the other one covering the poorly known small-x region x≈2×10- 3. Thus our new results could be used to further constrain the gluon polarization for x<5×10-2.

• Keywords (english): p+p collision; gluon polarization; helicity assymetry
• Language: english
• Publication type: Scientific paper - Original scientific paper
• Publication status: Published
• Peer review: Peer review - international
• Publication version: Published version
• Journal title: Physical Review D
• Numbering: vol. 94, no. 11, 112008
• p-ISSN: 2470-0029
• DOI: https://doi.org/10.1103/PhysRevD.94.112008
• URN:NBN: urn:nbn:hr:217:526062
• Publication: 2016
• Document URL: https://journals.aps.org/prd/abstract/10.1103/PhysRevD.94.112008
• Type of resource: Text
• Access conditions: Open access
• Public note: © 2016 American Physical Society. Received 19 August 2016. Published 29 December 2016.
• Created on: 2020-02-24 19:20:14