Parameter free calculation of hadronic masses from instantons

Nov, 2001
9 pages
Published in:
  • Phys.Rev.D 65 (2002) 094014
e-Print:

Citations per year

20022005200820112013301
Abstract:
We propose a non-perturbative calculation scheme which is based on the semi-classical approximation of QCD and can be used to evaluate quantities of interest in hadronic physics. As a first application, we evaluate the mass of the pion and of the nucleon. Such masses are related to a particular combination of Green functions which, in some limit, is dominated by the contribution of \emph{very small-sized} instantons. The size distribution of these pseudo-particles is determined by the 't Hooft tunneling amplitude formula and therefore our calculation is free from any model parameters. We prove that instanton forces generate a light pion and a nucleon with realistic mass (Mn970MeVM_n \sim 970 MeV). In connection with sum-rules approaches, we discuss the overlap of instantons with pion and nucleon resonances.
  • 12.38.Lg
  • pi: mass
  • nucleon: mass
  • instanton: force
  • quantum chromodynamics
  • approximation: semiclassical
  • nonperturbative
  • tunneling
  • sum rule
  • pi: resonance