Longitudinal double-spin asymmetry and cross section for inclusive neutral pion production at midrapidity in polarized proton collisions {radical}{ovr s} = 200 GeV.

Journal Article · Thu Jan 01 00:00:00 EST 2009 · Physical Review. D, Particles, Fields, Gravitation and Cosmology

DOI:https://doi.org/10.1103/PhysRevD.80.111108· OSTI ID:1050165

Abelev, B I; Aggarwal, M M; Ahammed, Z; Alakhverdyants, A V; Anderson, B D; Bridgeman, A; Krueger, K; Spinka, H M; Underwood, D G

We report a measurement of the longitudinal double-spin asymmetry A{sub LL} and the differential cross section for inclusive {pi}{sup 0} production at midrapidity in polarized proton collisions at {radical}s = 200 GeV. The cross section was measured over a transverse momentum range of 1 < p{sub T} < 17 GeV/c and found to be in good agreement with a next-to-leading order perturbative QCD calculation. The longitudinal double-spin asymmetry was measured in the range of 3.7 < p{sub T} < 11 GeV/c and excludes a maximal positive gluon polarization in the proton. The mean transverse momentum fraction of {pi}{sup 0}'s in their parent jets was found to be around 0.7 for electromagnetically triggered events.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC); National Science Foundation (NSF); Sloan Foundation; ESPRC - United Kingdom
• DOE Contract Number: DE-AC02-06CH11357
• OSTI ID: 1050165
• Report Number(s): ANL-HEP-PR-10-32; TRN: US1204545
• Journal Information: Physical Review. D, Particles, Fields, Gravitation and Cosmology, Vol. 80, Issue 11; ISSN 1550-7998
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ASYMMETRY
CROSS SECTIONS
DIFFERENTIAL CROSS SECTIONS
GLUONS
PIONS
POLARIZATION
PRODUCTION
PROTONS
QUANTUM CHROMODYNAMICS
TRANSVERSE MOMENTUM