Elsevier

Physics Letters B

Volume 317, Issues 1–2, 4 November 1993, Pages 250-256
Physics Letters B

Determination of αs and the gluon distribution using direct photon production in pp and pp collisions

https://doi.org/10.1016/0370-2693(93)91601-IGet rights and content

Abstract

Direct photon cross sections obtained in pp and pp collisions at √s = 24.3 GeV at the CERN SPS, are used in a next-to-leading order QCD analysis. From the cross-section difference σ(pp → γX) − σ (pp → γX), and quark distributions measured in deep inelastic scattering, a determination of the strong coupling constant, αs, is performed via a measurement of Λ(4)MS. This first measurement of Λ(4)MS using direct photon data yields a value Λ(4)MS = 235 ± 79 (stat.) ± 70 (syst.) MeV. The corresponding value of αs expressed at MZ2 is αs (MZ2) = 0.112±0.006 (stat.)±0.005 (syst.)−0.001+0.009 (theor.). The gluon distribution in the proton for x > 0.2 is determined both from the pp and from the pp data, and the results agree with each other and with previous determinations using the same method.

References (23)

  • P. Aurenche et al.

    Phys. Lett. B

    (1984)
    P. Aurenche et al.

    Nucl. Phys. B

    (1988)
  • A.C. Benvenuti

    Phys. Lett. B

    (1989)
    A.C. Benvenuti

    Phys. Lett. B

    (1989)
    A.C. Benvenuti

    Phys. Lett. B

    (1990)
    A.C. Benvenuti

    Phys. Lett. B

    (1990)
  • W. Furmanski et al.

    Z. Phys. C

    (1982)
  • W.A. Bardeen et al.

    Phys. Rev. D

    (1978)
  • P. Aurenche et al.

    Z. Phys. C

    (1990)
  • M. Virchaux et al.

    Phys. Lett. B

    (1992)
  • M. Bonesini

    Z. Phys. C

    (1988)
  • A.D. Martin et al.

    Phys. Rev. D

    (1993)
  • H. Plothow-Besch

    Comput. Phys. Commun.

    (1993)
  • P. Aurenche et al.

    Phys. Rev. D

    (1989)
  • UA6 Collab., G. Sozzi et al., previous...
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    1

    Present address: KEK 1-1-OHO, Tsukuba-Shi Ibaraki-Ken 305, Japan.

    2

    Deceased.

    3

    Present address: INFN, I-20133 Milan, Italy.

    4

    Present address: University of Virginia, VA 22901, USA.

    5

    Present address: Fermilab, Batavia, IL 60510, USA.

    6

    Present address: Università di Trieste, I-34127 Trieste, Italy.

    7

    Present address: INFN, I-40126 Bologna, Italy.

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