Photon-photon production in Hadron-Hadron collisions
Quantum Chromodynamic (QCD) estimates are made for the large transverse momentum production of single and double photons in pp, \(\overline p p\), and π±p collisions.In addition to the pure QED annihilation term \(q\overline q\) → γγ, it is found that the QCD induced gluon-gluon subprocess gg → γγ, is an important source of double photons. Photon Bremsstrahlung contributions are also examined.
KeywordsTransverse Momentum Photon Bremsstrahlung Naive Estimate Invariant Cross Section Photon Rate
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- 7.I have not included the effects of the parton intrinsic transverse momentum within the initial hadrons in the analysis presented here. The effect of “smearing” over the parton intrinsic transverse momentum is, however, important at low PT and in regions where the cross section is steeply falling. For example, smearing over the parton intrinsic transverse momentum can raise the W=27.4 GeV single photon rates by as much as a factor of two. On the other hand, the ratios of the double to single photon production presented in Figs. 2, 8, 11, and 14 are not affected greatly by smearing since I have not required the two photons to balance transverse momentum. The ratio simply measures the fraction of photon triggers that contain a photon on the away-side.Google Scholar
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