engleski

Spectral representation of nonperturbative quark propagators

We consider a fermion propagator possessing a spectral representation enabling positivity violation of spectral densities. In such a case there is no Källén–Lehmann representation, whereby the corresponding states cannot appear in the spectrum of physical particles. This is very suitable for representing quark propagators in the nonperturbative regime of QCD, where confinement is essential. Phenomenological consequences of this propagator are investigated for the lightest quark-antiquark composites - the charged and neutral pions.

non-perturbative QCD ; quark propagator ; spectral representation ; analytic

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