Certain Uncertainties in QCD Theory Predictions for Large-PT Photons and Other Processes

  • A. P. Contogouris
Part of the NATO ASI Series book series (NSSB, volume 197)


In general there are more than one scale (large variable) determining perturbative QCD quantities: E.g. the renormalization scale μ entering the running coupling α 8 (μ) (related with the renormalization procedure), and the factorization scale M entering the structure functions F(x,M) (determining the scale violations). Until recently, for large transverse momentum P T ) processes, simplicity suggested the choice
$${{\mu }^{2}}={{M}^{2}}=\alpha p_{T}^{2}$$
where α = positive and of 0(1), or other choices phenomenologically equivalent; hereafter P T will be called physical scale.


Gluon Distribution Soft Gluon Physical Scale Inclusive Cross Section Direct Photon 
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Copyright information

© Plenum Press, New York 1988

Authors and Affiliations

  • A. P. Contogouris
    • 1
  1. 1.Department of PhysicsMcGill UniversityMontrealCanada

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