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Title: Measurement of transverse single-spin asymmetries for dijet production in proton-proton collisions at {radical}{ovr s} = 200 GeV.

Abstract

We report the first measurement of the opening angle distribution between pairs of jets produced in high-energy collisions of transversely polarized protons. The measurement probes (Sivers) correlations between the transverse spin orientation of a proton and the transverse momentum directions of its partons. With both beams polarized, the wide pseudorapidity (-1 {le} {eta} {le} +2) coverage for jets permits separation of Sivers functions for the valence and sea regions. The resulting asymmetries are all consistent with zero and considerably smaller than Sivers effects observed in semi-inclusive deep inelastic scattering. We discuss theoretical attempts to reconcile the new results with the sizable transverse spin effects seen in semi-inclusive deep inelastic scattering and forward hadron production in pp collisions.

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC); National Science Foundation (NSF); Swiss NSF
OSTI Identifier:
967042
Report Number(s):
ANL-HEP-PR-09-89
Journal ID: ISSN 0031-9007; PRLTAO; TRN: US0904169
DOE Contract Number:
DE-AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Phys. Rev. Lett.; Journal Volume: 99; Journal Issue: 2007
Country of Publication:
United States
Language:
ENGLISH
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; DEEP INELASTIC SCATTERING; DISTRIBUTION; HADRONS; OPENINGS; PROBES; PRODUCTION; PROTONS; SEAS; SPIN; SPIN ORIENTATION; TRANSVERSE MOMENTUM; VALENCE

Citation Formats

Abelev, B. I., Aggarwal, M. M., Ahammed, Z., Anderson, B. D., Arkhipkin, D., Krueger, K., Spinka, H. M., Underwood, D. G., STAR Collaboration, High Energy Physics, Univ. of Illinois, Panjab Univ., Variable Energy Cyclotron Centre, Kent State Univ., and Particle Physic Lab.. Measurement of transverse single-spin asymmetries for dijet production in proton-proton collisions at {radical}{ovr s} = 200 GeV.. United States: N. p., 2007. Web. doi:10.1103/PhysRevLett.99.142003.
Abelev, B. I., Aggarwal, M. M., Ahammed, Z., Anderson, B. D., Arkhipkin, D., Krueger, K., Spinka, H. M., Underwood, D. G., STAR Collaboration, High Energy Physics, Univ. of Illinois, Panjab Univ., Variable Energy Cyclotron Centre, Kent State Univ., & Particle Physic Lab.. Measurement of transverse single-spin asymmetries for dijet production in proton-proton collisions at {radical}{ovr s} = 200 GeV.. United States. doi:10.1103/PhysRevLett.99.142003.
Abelev, B. I., Aggarwal, M. M., Ahammed, Z., Anderson, B. D., Arkhipkin, D., Krueger, K., Spinka, H. M., Underwood, D. G., STAR Collaboration, High Energy Physics, Univ. of Illinois, Panjab Univ., Variable Energy Cyclotron Centre, Kent State Univ., and Particle Physic Lab.. Mon . "Measurement of transverse single-spin asymmetries for dijet production in proton-proton collisions at {radical}{ovr s} = 200 GeV.". United States. doi:10.1103/PhysRevLett.99.142003.
@article{osti_967042,
title = {Measurement of transverse single-spin asymmetries for dijet production in proton-proton collisions at {radical}{ovr s} = 200 GeV.},
author = {Abelev, B. I. and Aggarwal, M. M. and Ahammed, Z. and Anderson, B. D. and Arkhipkin, D. and Krueger, K. and Spinka, H. M. and Underwood, D. G. and STAR Collaboration and High Energy Physics and Univ. of Illinois and Panjab Univ. and Variable Energy Cyclotron Centre and Kent State Univ. and Particle Physic Lab.},
abstractNote = {We report the first measurement of the opening angle distribution between pairs of jets produced in high-energy collisions of transversely polarized protons. The measurement probes (Sivers) correlations between the transverse spin orientation of a proton and the transverse momentum directions of its partons. With both beams polarized, the wide pseudorapidity (-1 {le} {eta} {le} +2) coverage for jets permits separation of Sivers functions for the valence and sea regions. The resulting asymmetries are all consistent with zero and considerably smaller than Sivers effects observed in semi-inclusive deep inelastic scattering. We discuss theoretical attempts to reconcile the new results with the sizable transverse spin effects seen in semi-inclusive deep inelastic scattering and forward hadron production in pp collisions.},
doi = {10.1103/PhysRevLett.99.142003},
journal = {Phys. Rev. Lett.},
number = 2007,
volume = 99,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • We report the first measurement of the opening angle distribution between pairs of jets produced in high-energy collisions of transversely polarized protons. The measurement probes (Sivers) correlations between the transverse spin orientation of a proton and the transverse momentum directions of its partons. With both beams polarized, the wide pseudorapidity (-1{<=}{eta}{<=}+2) coverage for jets permits separation of Sivers functions for the valence and sea regions. The resulting asymmetries are all consistent with zero and considerably smaller than Sivers effects observed in semi-inclusive deep inelastic scattering. We discuss theoretical attempts to reconcile the new results with the sizable transverse spin effectsmore » seen in semi-inclusive deep inelastic scattering and forward hadron production in pp collisions.« less
  • We report precision measurements of the Feynman x (x{sub F}) dependence, and first measurements of the transverse momentum (p{sub T}) dependence, of transverse single-spin asymmetries for the production of {pi}{sup 0} mesons from polarized proton collisions at {radical}s = 200 GeV. The x{sub F} dependence of the results is in fair agreement with perturbative QCD model calculations that identify orbital motion of quarks and gluons within the proton as the origin of the spin effects. Results for the p{sub T} dependence at fixed x{sub F} are not consistent with these same perturbative QCD-based calculations.
  • Transverse single-spin asymmetries to probe the transverse-spin structure of the proton have been measured for neutral pions and nonidentified charged hadrons from polarized proton-proton collisions at midrapidity and {radical}(s)=200 GeV. The data cover a transverse momentum (p{sub T}) range 1.0-5.0 GeV/c for neutral pions and 0.5-5.0 GeV/c for charged hadrons, at a Feynman-x value of approximately zero. The asymmetries seen in this previously unexplored kinematic region are consistent with zero within errors of a few percent. In addition, the inclusive charged hadron cross section at midrapidity from 0.5<p{sub T}<7.0 GeV/c is presented and compared to next-to-leading order perturbative QCD (pQCD)more » calculations. Successful description of the unpolarized cross section above {approx}2 GeV/c suggests that pQCD is applicable in the interpretation of the asymmetry results in the relevant kinematic range.« less
  • We report the first measurement of the opening angledistribution between pairs of jets produced in high-energy collisions oftransversely polarized protons. The measurement probes (Sivers)correlations between the transverse spin orientation of a proton and thetransverse momentum directions of its partons. With both beams polarized,the wide pseudorapidity (-1 leq eta leq +2) coverage for jets permitsseparation of Sivers functions for the valence and sea regions. Theresulting asymmetries are all consistent with zero and considerablysmaller than Sivers effects observed in semi-inclusive deep inelasticscattering (SIDIS). We discuss theoretical attempts to reconcile the newresults with the sizable transverse spin effects seen in SIDIS andforward hadronmore » production in pp collisions.« less
  • No abstract prepared.