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

Autori
Adare, A. ; ... ; Makek, Mihael ; ... ; Zou, L.

Kolaboracija
PHENIX Collaboration

Izvornik
Physical review. D (2470-0010) 94 (2016), 11; 112008, 10

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
p+p collision ; gluon polarization ; helicity assymetry

Sažetak
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.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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