Inclusive cross section and double helicity asymmetry for Pi0 production in p+p collisions at sqrt(s)=200 GeV: Implications for the polarized gluon distribution in the proton
Result description
The PHENIX experiment presents results from the Relativistic Heavy Ion Collider 2005 run with polarized proton collisions at root s=200 GeV, for inclusive pi(0) production at midrapidity. Unpolarized cross section results are given for transverse momentap(T)=0.5 to 20 GeV/c, extending the range of published data to both lower and higher p(T). The cross section is described well for p(T)< 1 GeV/c by an exponential in p(T), and, for p(T)> 2 GeV/c, by perturbative QCD. Double helicity asymmetries A(LL) are presented based on a factor of 5 improvement in uncertainties as compared to previously published results, due to both an improved beam polarization of 50%, and to higher integrated luminosity. These measurements are sensitive to the gluon polarizationin the proton. Using one representative model of gluon polarization it is demonstrated that the gluon spin contribution to the proton spin is significantly constrained.
Keywords
asymmetryhelicityinclusive cross sectionpi0 productionpolarized gluon distribution
The result's identifiers
Result code in IS VaVaI
Alternative codes found
RIV/00216208:11320/07:10084091
Result on the web
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DOI - Digital Object Identifier
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Alternative languages
Result language
angličtina
Original language name
Inclusive cross section and double helicity asymmetry for Pi0 production in p+p collisions at sqrt(s)=200 GeV: Implications for the polarized gluon distribution in the proton
Original language description
The PHENIX experiment presents results from the Relativistic Heavy Ion Collider 2005 run with polarized proton collisions at root s=200 GeV, for inclusive pi(0) production at midrapidity. Unpolarized cross section results are given for transverse momentap(T)=0.5 to 20 GeV/c, extending the range of published data to both lower and higher p(T). The cross section is described well for p(T)< 1 GeV/c by an exponential in p(T), and, for p(T)> 2 GeV/c, by perturbative QCD. Double helicity asymmetries A(LL) are presented based on a factor of 5 improvement in uncertainties as compared to previously published results, due to both an improved beam polarization of 50%, and to higher integrated luminosity. These measurements are sensitive to the gluon polarizationin the proton. Using one representative model of gluon polarization it is demonstrated that the gluon spin contribution to the proton spin is significantly constrained.
Czech name
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Czech description
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Classification
Type
Jx - Unclassified - Peer-reviewed scientific article (Jimp, Jsc and Jost)
CEP classification
BF - Elementary particle theory and high energy physics
OECD FORD branch
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Result continuities
Project
Result was created during the realization of more than one project. More information in the Projects tab.
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)
Others
Publication year
2007
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Physical Review D
ISSN
1550-7998
e-ISSN
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Volume of the periodical
76
Issue of the periodical within the volume
5
Country of publishing house
US - UNITED STATES
Number of pages
7
Pages from-to
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UT code for WoS article
000249786800006
EID of the result in the Scopus database
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Basic information
Result type
Jx - Unclassified - Peer-reviewed scientific article (Jimp, Jsc and Jost)
CEP
BF - Elementary particle theory and high energy physics
Year of implementation
2007