Inclusive cross section and double-helicity asymmetry for π0 production at midrapidity in p + p collisions at √s=510 GeV

Adare, A. and Makek, Mihael and Zou, L. (PHENIX Collaboration) (2016) Inclusive cross section and double-helicity asymmetry for π0 production at midrapidity in p + p collisions at √s=510 GeV. Physical Review D, 93 (1). pp. 11501-8. ISSN 1550-7998

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Abstract

PHENIX measurements are presented for the cross section and double-helicity asymmetry (ALL) in inclusive π^0 production at midrapidity from p+p collisions at √s=510  GeV from data taken in 2012 and 2013 at the Relativistic Heavy Ion Collider. The next-to-leading-order perturbative-quantum-chromodynamics theory calculation is in excellent agreement with the presented cross section results. The calculation utilized parton-to-pion fragmentation functions from the recent DSS14 global analysis, which prefer a smaller gluon-to-pion fragmentation function. The π^0ALLresults follow an increasingly positive asymmetry trend with pT and √s with respect to the predictions and are in excellent agreement with the latest global analysis results. This analysis incorporated earlier results on π^0 and jet ALL and suggested a positive contribution of gluon polarization to the spin of the proton ΔG for the gluon momentum fraction range x>0.05. The data presented here extend to a currently unexplored region, down to x∼0.01, and thus provide additional constraints on the value of ΔG.

Item Type: Article
Date: 7 January 2016
Subjects: NATURAL SCIENCES > Physics
Additional Information: Copyright (2016) by the American Physical Society. Received 8 October 2015; published 7 January 2016.
Divisions: Faculty of Science > Department of Physics
Publisher: American Physical Society
Depositing User: Gordana Stubičan Ladešić
Date Deposited: 03 Feb 2016 13:21
Last Modified: 03 Feb 2016 13:21
URI: http://digre.pmf.unizg.hr/id/eprint/4498

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