Tests of QCD in Two Photon Collisions and High p(t) Photon Production

Jan, 1979
62 pages
Published in:
  • Phys.Rev.D 20 (1979) 147
Report number:
  • UCD-78-5,
  • UCSD-10P10-199

Citations per year

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Abstract: (APS)
We use the diagrammatic approach to scale breaking to rederive the results of the renormalization-group approach to two-photon, γ*γ, collisions, where one of the photons is highly virtual and the other nearly real. In an axial gauge only ladder diagrams contribute to leading-logarithmic accuracy. When interpreted in terms of the quark distribution of the real photon we obtain the result Gqγ(q2,x)=[ααs(q2)]f̃q(x)+O(1), where f̃q(x) is an exactly calculable scaling function. By virtue of the fact that only ladder diagrams contribute in leading-logarithmic accuracy for this and other short-distance photon-target probes, we find that this form for Gqγ can be employed (to leading-logarithmic accuracy) in any short-distance application involving a photon target. We give a summary of these additional applications with emphasis on high-transverse-momentum phenomena. We present also estimates of the vector-dominance background to the pointlike component of the photon distribution function. In addition we present a convenient summary of leading-logarithmic quantum-chromodynamic corrections including dominant x→1 behaviors.
  • QUANTUM CHROMODYNAMICS: VALIDITY TEST
  • PHOTON PHOTON: INTERACTION
  • INTERACTION: PHOTON PHOTON
  • TRANSVERSE MOMENTUM: HIGH
  • SCALING: VIOLATION
  • RENORMALIZATION GROUP
  • APPROXIMATION: LADDER
  • APPROXIMATION: LEADING LOGARITHM
  • PHOTON: STRUCTURE FUNCTION
  • MOMENT