Axial vector current matrix elements and QCD sum rules

Pasupathy, J. ; Singh, Ritesh K. (2006) Axial vector current matrix elements and QCD sum rules International Journal of Modern Physics A, 21 (25). pp. 5099-5117. ISSN 0217-751X

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Official URL: http://www.worldscinet.com/ijmpa/21/2125/S0217751X...

Related URL: http://dx.doi.org/10.1142/S0217751X06032563

Abstract

The matrix element of the isoscalar axial vector current,u-γμ γ5u+d-γμ γ5d , between nucleon states is computed using the external field QCD sum rule method. The external field induced correlator,(0|q-γμ γ5 , is calculated from the spectrum of the isoscalar axial vector meson states. Since it is difficult to ascertain, from QCD sum rule for hyperons, the accuracy of validity of flavor SU(3) symmetry in hyperon decays when strange quark mass is taken into account, we rely on the empirical validity of Cabbibo theory to determine the matrix element u-γμγ5u+d-γμγ5d-2s-γ μγ5s between nucleon states. Combining with our calculation of u-γμ γ5u+d-γμ γ5d and the well-known nucleon β-decay constant allows us to determine(p,s|4/9u-γμγ5u+1/9d-γμγ5d+1/9s-γμγ5s|p,s) occurring in the Bjorken sum rule. The result is in reasonable agreement with experiment. We also discuss the role of the anomaly in maintaining flavor symmetry and validity of OZI rule.

Item Type:Article
Source:Copyright of this article belongs to World Scientific Publishing Company.
Keywords:Proton Spin; Bjorken Sum Rule; Axial Vector Current; Anomaly; QCD Sum Rules
ID Code:58105
Deposited On:31 Aug 2011 12:40
Last Modified:31 Aug 2011 12:40

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