Double distributions and evolution equations

Journal Article · Fri Jan 01 04:00:00 EST 1999 · Physical Review, D

DOI:https://doi.org/10.1103/PhysRevD.59.014030· OSTI ID:289057

Radyushkin, A V ^[1]

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1. Department of Physics, Old Dominion University, Norfolk, Virginia 23529 (United States)

Applications of perturbative QCD to deeply virtual Compton scattering and hard exclusive meson electroproduction processes require a generalization of usual parton distributions for the case when long-distance information is accumulated in nonforward matrix elements {l_angle}p{sup {prime}}{vert_bar}O(0,z){vert_bar}p{r_angle} of quark and gluon light-cone operators. In our previous papers we used two types of nonperturbative functions parametrizing such matrix elements: double distributions F(x,y;t) and nonforward distribution functions F{sub {zeta}}(X;t). Here we discuss in more detail the double distributions (DD{close_quote}s) and evolution equations which they satisfy. We propose simple models for F(x,y;t=0) DD{close_quote}s with correct spectral and symmetry properties which also satisfy the reduction relations connecting them to the usual parton densities f(x). In this way, we obtain self-consistent models for the {zeta} dependence of nonforward distributions. We show that, for small {zeta}, one can easily obtain nonforward distributions (in the X{gt}{zeta} region) from the parton densities: F{sub {zeta}}(X;t=0){approx}f(X{minus}{zeta}/2). {copyright} {ital 1998} {ital The American Physical Society}

• OSTI ID: 289057
• Journal Information: Physical Review, D, Journal Name: Physical Review, D Journal Issue: 1 Vol. 59; ISSN 0556-2821; ISSN PRVDAQ
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
COMPTON EFFECT
ELECTRON-NUCLEON INTERACTIONS
ELECTROPRODUCTION
GLUONS
MATRIX ELEMENTS
MESONS
PARTON MODEL
QUANTUM CHROMODYNAMICS
QUARKS