Isolated prompt photon production in hadronic final states of {ital e}{sup +}{ital e}{sup {minus}} annihilation

Journal Article · Thu Oct 31 23:00:00 EST 1996 · Physical Review, D

DOI:https://doi.org/10.1103/PhysRevD.54.5470· OSTI ID:392064

Berger, E L ^[1]; Guo, X; Qiu, J ^[2]

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1. High Energy Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
2. Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States)

We provide complete analytic expressions for the isolated prompt photon production cross section in {ital e}{sup +}{ital e}{sup {minus}} annihilation reactions through one-loop order in quantum chromodynamics (QCD) perturbation theory. Functional dependences on the isolation cone size {delta} and isolation energy parameter {epsilon} are derived. The energy dependence as well as the full angular dependence of the cross section on {theta}{sub {gamma}} are displayed, where {theta}{sub {gamma}} specifies the direction of the photon with respect to the {ital e}{sup +}{ital e}{sup {minus}} collision axis. We point out that conventional perturbative QCD factorization breaks down for isolated photon production in {ital e}{sup +}{ital e}{sup {minus}} annihilation reactions in a specific region of phase space. We discuss the implications of this breakdown for the extraction of fragmentation functions from {ital e}{sup +}{ital e}{sup {minus}} annihilation data and for computations of prompt photon production in hadron-hadron reactions. {copyright} {ital 1996 The American Physical Society.}

• DOE Contract Number: FG02-92ER40731; FG02-92ER40730; W-31109-ENG-38
• OSTI ID: 392064
• Journal Information: Physical Review, D, Journal Name: Physical Review, D Journal Issue: 9 Vol. 54; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ANNIHILATION
CROSS SECTIONS
ELECTRON-POSITRON INTERACTIONS
ENERGY DEPENDENCE
FACTORIZATION
FRAGMENTATION
HADRON-HADRON INTERACTIONS
PARTICLE PRODUCTION
PERTURBATION THEORY
PHASE SPACE
PHOTONS
QUANTUM CHROMODYNAMICS