Optimal renormalization scale and scheme for exclusive processes

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ID: 270250
1998
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Abstract
We use the Brodsky-Lepage-Mackenzie (BLM) method to fix the renormalization scale of the QCD coupling in exclusive hadronic amplitudes such as the pion form factor and the photon-to-pion transition form factor at large momentum transfer. Renormalization-scheme-independent commensurate scale relations are established which connect the hard scattering subprocess amplitudes that control exclusive processes to other QCD observables such as the heavy quark potential and the electron-positron annihilation cross section. The commensurate scale relation connecting the heavy quark potential, as determined from lattice gauge theory, to the photon-to-pion transition form factor is in excellent agreement with γe→π0e data assuming that the pion distribution amplitude is close to its asymptotic form 3fπx(1−x). We also reproduce the scaling and normalization of the γγ→π+π− data at large momentum transfer. Because the renormalization scale is small, we argue that the effective coupling is nearly constant, thus accounting for the nominal scaling behavior of the data. However, the normalization of the space-like pion form factor Fπ(Q2) obtained from electroproduction experiments is somewhat higher than that predicted by the corresponding commensurate scale relation. This discrepancy may be due to systematic errors introduced by the extrapolation of the γ*p→π+n electroproduction data to the pion pole.
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robertson1998physicaloptimal Use this key to autocite in the manuscript while using SciMatic Manuscript Manager or Thesis Manager
Authors Stanley J. Brodsky,Chueng-Ryong Ji,Alex Pang,David G. Robertson;Stanley J. Brodsky;Chueng-Ryong Ji;Alex Pang;David G. Robertson;
Journal physical review d
Year 1998
DOI
10.1103/physrevd.57.245
URL
https://sciprofiles.com/publication/view/f69349e50fae37c86cb99457eaa86eb6
Keywords
physics scaling cross section renormalization quarks quantum chromodynamics perturbation theory scattering amplitude momentum transfer pions form factor coupling renormalization group lattice gauge theory systematic error scattering amplitudes

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