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Johan Bijnens in front of his whiteboard

Johan Bijnens

Professor, Deputy Head of Division

Johan Bijnens in front of his whiteboard

Low-energy behaviour of two-point functions of quark currents

Author

  • Johan Bijnens
  • Eduardo de Rafael
  • Hanqing Zheng

Summary, in English

We discuss vector, axial-vector, scalar and pseudoscalar two-point functions at low and intermediate energies. We first review what is known from chiral perturbation theory, as well as from a heat kernel expansion within the context of an extended Nambu-Jona-Lasinio (ENJL) model. We derive then these two-point functions to all orders in the momenta and to leading order in 1/N c within the framework of this model. We find an improved high-energy behaviour and a general way of parametrizing them that shows relations between some of the two-point functions, which are also valid in the presence of gluonic interactions. The similarity between the shape of the experimentally known spectral functions and the ones we derive, is greatly improved with respect to those predicted by the usual constituent quark like models. We also obtain the scalar mass M s =2 M Q independent of the regularization scheme. In the end, we calculate fully an example of a nonleptonic matrix element in the ENJL-model, the π + -π 0 electromagnetic mass difference and find good agreement with the measured value.

Publishing year

1994-09-01

Language

English

Pages

437-454

Publication/Series

Zeitschrift für Physik C Particles and Fields

Volume

62

Issue

3

Document type

Journal article

Publisher

Springer

Topic

  • Subatomic Physics

Status

Published

ISBN/ISSN/Other

  • ISSN: 0170-9739