The principle of minimum sensitivity and moments of nonsinglet structure functions

1983 ◽  
Vol 61 (1) ◽  
pp. 99-101 ◽  
Author(s):  
Gerry McKeon
Keyword(s):  
Perturbation Theory ◽  
Quantum Chromodynamics ◽  
Finite Order ◽  
Parton Model ◽  
Structure Functions ◽  
Renormalization Procedure ◽  
Dependent Part ◽  
Model Predictions ◽  
Minimum Sensitivity

The corrections implied by quantum chromodynamics to parton model predictions are not unique to finite order in perturbation theory on account of the possibility of choosing different renormalization schemes. Stevenson has provided a criterion for selecting the "best" renormalization procedure; the so-called "principle of minimum sensitivity" (PMS). This criterion is applied here to the Q2-dependent part of the moments of the nonsinglet structure functions in lepton–hadron scattering.

Measuring the scale parameter of quantum chromodynamics at CHEER

1981 ◽  
Vol 59 (11) ◽  
pp. 1769-1773
Author(s):  
Lawrence M. Krauss
Keyword(s):  
Quantum Chromodynamics ◽  
Scale Parameter ◽  
Structure Functions ◽  
High Q ◽  
Advantages And Disadvantages ◽  
Almost All

The possibility of measuring the scale parameter of quantum chromodynamics, Λs, at CHEER is discussed. Rationale for the measurement of this quantity are given, along with a discussion of the theoretical difficulties involved. The measurement of the Q2 dependence of structure functions and their moments, and methods of measuring αs and its Q2 evolution, are discussed, and arguments are given for the advantages and disadvantages of going to high Q2 values at CHEER. It is concluded that while sensitivity to Λ is lowered at high Q2, CHEER will, in principle, be able to provide the first clean measurements of Λ, free from almost all the theoretical confusion involved in interpretations of present data.

scholarly journals The Leutwyler–Smilga relation on the lattice

2019 ◽  
Vol 35 (01) ◽  
pp. 1950346 ◽  
Author(s):  
Gernot Münster ◽  
Raimar Wulkenhaar
Keyword(s):  
Perturbation Theory ◽  
Quantum Chromodynamics ◽  
Lattice Qcd ◽  
Chiral Perturbation Theory ◽  
Effective Action ◽  
Lattice Spacing ◽  
Chiral Perturbation ◽  
Quark Masses

According to the Leutwyler–Smilga relation, in Quantum Chromodynamics (QCD), the topological susceptibility vanishes linearly with the quark masses. Calculations of the topological susceptibility in the context of lattice QCD, extrapolated to zero quark masses, show a remnant nonzero value as a lattice artefact. Employing the Atiyah–Singer theorem in the framework of Symanzik’s effective action and chiral perturbation theory, we show the validity of the Leutwyler–Smilga relation in lattice QCD with lattice artefacts of order a2 in the lattice spacing a.

Measurement of Separated Structure Functions in thep(e,e′p)π0Reaction at Threshold and Chiral Perturbation Theory

1998 ◽  
Vol 80 (11) ◽  
pp. 2294-2297 ◽  
Author(s):  
M. O. Distler ◽  
A. M. Bernstein ◽  
K. I. Blomqvist ◽  
W. U. Boeglin ◽  
R. Böhm ◽  
...  
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Structure Functions ◽  
Chiral Perturbation
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