Gluon-spin contribution to the proton spin from the double-helicity asymmetry in inclusive pi0 production in polarized p+p collisions at [sqrt]s=200 GeV

The double helicity asymmetry in neutral pion production for pT=1 to 12 GeV/c was measured with the PHENIX experiment to access the gluon-spin contribution, DeltaG, to the proton spin. Measured asymmetries are consistent with zero, and at a theory scale of micro2=4 GeV2 a next to leading order QCD a...

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Bibliographic Details
Published in:Physical review letters 2009-07, Vol.103 (1), p.012003-012003
Main Authors: Adare, A, Afanasiev, S, Aidala, C, Ajitanand, N N, Akiba, Y, Al-Bataineh, H, Alexander, J, Aoki, K, Aphecetche, L, Asai, J, Atomssa, E T, Averbeck, R, Awes, T C, Azmoun, B, Babintsev, V, Bai, M, Baksay, G, Baksay, L, Baldisseri, A, Barish, K N, Barnes, P D, Bassalleck, B, Basye, A T, Bathe, S, Batsouli, S, Baublis, V, Baumann, C, Bazilevsky, A, Belikov, S, Bennett, R, Berdnikov, A, Berdnikov, Y, Bickley, A A, Boissevain, J G, Borel, H, Boyle, K, Brooks, M L, Buesching, H, Bumazhnov, V, Bunce, G, Butsyk, S, Camacho, C M, Campbell, S, Chand, P, Chang, B S, Chang, W C, Charvet, J-L, Chernichenko, S, Chi, C Y, Chiu, M, Choi, I J, Choudhury, R K, Chujo, T, Chung, P, Churyn, A, Cianciolo, V, Citron, Z, Cole, B A, Constantin, P, Csanád, M, Csörgo, T, Dahms, T, Dairaku, S, Das, K, David, G, Denisov, A, d'Enterria, D, Deshpande, A, Desmond, E J, Dietzsch, O, Dion, A, Donadelli, M, Drapier, O, Drees, A, Drees, K A, Dubey, A K, Durum, A, Dutta, D, Dzhordzhadze, V, Efremenko, Y V, Egdemir, J, Ellinghaus, F, Engelmore, T, Enokizono, A, En'yo, H, Esumi, S, Eyser, K O, Fadem, B, Fields, D E, Finger, M, Finger, Jr, M, Fleuret, F, Fokin, S L, Fraenkel, Z, Frantz, J E, Franz, A, Frawley, A D, Fujiwara, K, Fukao, Y, Fusayasu, T
Format: Article
Language:English
Subjects:
ASYMMETRY
CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS
DEEP INELASTIC SCATTERING
GLUONS
HELICITY
PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
PIONS
PRODUCTION
PROTONS
QUANTUM CHROMODYNAMICS
SPIN
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Summary:The double helicity asymmetry in neutral pion production for pT=1 to 12 GeV/c was measured with the PHENIX experiment to access the gluon-spin contribution, DeltaG, to the proton spin. Measured asymmetries are consistent with zero, and at a theory scale of micro2=4 GeV2 a next to leading order QCD analysis gives DeltaG[0.02,0.3]=0.2, with a constraint of -0.7
ISSN:0031-9007
1079-7114
DOI:10.1103/PhysRevLett.103.012003