Evolution Equations for QCD String Operators
Dec, 198744 pages
Published in:
- Nucl.Phys.B 311 (1989) 541-584
- Published: 1989
Report number:
- LENINGRAD-87-1351
Citations per year
Abstract: (Elsevier)
It is shown that all of the usual programs for the operator expansion can be performed in terms of string operators on the light cone; namely, the separation of contributions from large and small distances, the study of higher twist corrections and the renormalization group analysis. Evolution equations for the leading-twist QCD string operators such as g ̄ y(x)P exp (ig∫ C A μ d x μ )ψ(0) are studied in the coordinate space, which has an advantage of preserving explicitly the Lorentz and (in one-loop) conformal invariance of the theory. The solution is found, relating the two string operators in different normalization points. Its short-distance expansion reproduces conventional results for the summation of leading logs in deep inelastic scattering and evolution of hadron wave functions. The light-cone expansion of string operators provides an effective covariant technique for a separation of higher twist effects. As an illustration we calculate the twist-three and twist-four corrections for the deep inelastic scattering and confirm in this way the recent results on the renormalization of twist-three operators.- QUANTUM CHROMODYNAMICS
- MODEL: STRING
- FIELD THEORY: OPERATOR PRODUCT EXPANSION
- EFFECT: HIGHER-TWIST
- OPERATOR: EXPANSION
- LIGHT CONE BEHAVIOR
- RENORMALIZATION GROUP
- INTERFERENCE: (QUARK GLUON)
- INVARIANCE: CONFORMAL
- INVARIANCE: LORENTZ
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