On the Ambiguity of Composite Operators, ir Renormalons and the Status of the Operator Product Expansion

1990 ◽  
pp. 493-507
Author(s):  
F. DAVID
Keyword(s):  
Operator Product Expansion ◽  
Operator Product ◽  
The Status

THE OPERATOR PRODUCT EXPANSION OF THE QCD PROPAGATORS

1992 ◽  
Vol 07 (39) ◽  
pp. 3617-3630 ◽  
Author(s):  
MARTIN LAVELLE ◽  
MICHAEL OLESZCZUK
Keyword(s):  
Operator Product Expansion ◽  
Arbitrary Dimension ◽  
Light Quark ◽  
Equations Of Motion ◽  
Internal Symmetry ◽  
Operator Product ◽  
General Belief ◽  
Quark Masses ◽  
Acceleration Technique ◽  
The Status

We bring together for the first time the coefficients in covariant gauges of all the condensates of dimension four or less in the operator product expansion (OPE) of the quark, gluon and ghost propagators. It is stressed that contrary to general belief the condensates do not enter the OPE of the propagators in gauge-invariant combinations like [Formula: see text] and 〈G2〉. The results are presented in arbitrary dimension to lowest order in the light quark masses for the SU (Nc) internal symmetry group. All terms which, through the equations of motion, may be viewed as being effectively of order αs are included. The importance of the equations of motion if one is to fulfill the Slavnov-Taylor identities is demonstrated. We briefly consider the equivalent, but less complete, calculations in other gauges and give an overview of the status of the OPE of the QCD vertices. Finally we discuss what these non-perturbative structures tell us about the correct solutions of QCD and point out their significance for the Fourier acceleration technique as applied to lattice QCD.

scholarly journals High-energy operator product expansion at sub-eikonal level

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Giovanni Antonio Chirilli
Keyword(s):  
Operator Product Expansion ◽  
Evolution Equations ◽  
Energy Operator ◽  
High Energy ◽  
Structure Functions ◽  
Distribution Functions ◽  
Impact Factors ◽  
Operator Product ◽  
The Impact ◽  
New Distribution

Abstract The high energy Operator Product Expansion for the product of two electromagnetic currents is extended to the sub-eikonal level in a rigorous way. I calculate the impact factors for polarized and unpolarized structure functions, define new distribution functions, and derive the evolution equations for unpolarized and polarized structure functions in the flavor singlet and non-singlet case.

scholarly journals Conformal Regge theory at finite boost

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Simon Caron-Huot ◽  
Joshua Sandor
Keyword(s):  
Field Theory ◽  
Operator Product Expansion ◽  
Operator Product ◽  
Exact Results ◽  
Double Integral ◽  
Regge Theory ◽  
Conformal Field ◽  
Regge Trajectories ◽  
Continuous Spins ◽  
Regge Limit

Abstract The Operator Product Expansion is a useful tool to represent correlation functions. In this note we extend Conformal Regge theory to provide an exact OPE representation of Lorenzian four-point correlators in conformal field theory, valid even away from Regge limit. The representation extends convergence of the OPE by rewriting it as a double integral over continuous spins and dimensions, and features a novel “Regge block”. We test the formula in the conformal fishnet theory, where exact results involving nontrivial Regge trajectories are available.

Operator product expansion in the minimal subtraction scheme

1982 ◽  
Vol 119 (4-6) ◽  
pp. 407-411 ◽  
Author(s):  
K.G. Chetyrkin ◽  
S.G. Gorishny ◽  
F.V. Tkachov
Keyword(s):  
Operator Product Expansion ◽  
Operator Product ◽  
Minimal Subtraction ◽  
Subtraction Scheme ◽  
Minimal Subtraction Scheme

scholarly journals OPERATOR-PRODUCT EXPANSION AND ANALYTICITY

1999 ◽  
Vol 14 (30) ◽  
pp. 4819-4840
Author(s):  
JAN FISCHER ◽  
IVO VRKOČ
Keyword(s):  
Operator Product Expansion ◽  
Deflection Angle ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Operator Product ◽  
Coupling Constant ◽  
Expectation Value ◽  
Euclidean Region ◽  
The Deflection Angle ◽  
Class Of Functions

We discuss the current use of the operator-product expansion in QCD calculations. Treating the OPE as an expansion in inverse powers of an energy-squared variable (with possible exponential terms added), approximating the vacuum expectation value of the operator product by several terms and assuming a bound on the remainder along the Euclidean region, we observe how the bound varies with increasing deflection from the Euclidean ray down to the cut (Minkowski region). We argue that the assumption that the remainder is constant for all angles in the cut complex plane down to the Minkowski region is not justified. Making specific assumptions on the properties of the expanded function, we obtain bounds on the remainder in explicit form and show that they are very sensitive both to the deflection angle and to the class of functions considered. The results obtained are discussed in connection with calculations of the coupling constant αs from the τ decay.

Sign in / Sign up

Export Citation Format

Share Document