Evidence for quenched chiral logs

Evidence for Quenched Chiral Logs *

Using the pole shifting procedure of the modified quenched approximation (MQA) to cure the exceptional configuration problem, accurate hadron spectrum calculations can be obtained at very light quark mass. Here we use the MQA to extend and improve our previous investigation of chiral logs in the pion mass. At β = 5.7 for Wilson fermions, we see clear evidence for quenched chiral logarithms in t...

Evidence for hard chiral logarithms in quenched lattice QCD.

Quenched chiral logarithms.

I develop a diagrammatic method for calculating chiral logarithms in the quenched approximation. While not rigorous, the method is based on physically reasonable assumptions, which can be tested by numerical simulations. The main results are that, at leading order in the chiral expansion, (a) there are no chiral logarithms in quenched fπ, for mu = md; (b) the chiral logarithms in BK and related...

Quenched Chiral Perturbation Theory

Partially quenched theories are theories in which the valenceand seaquark masses are different. In this paper we calculate the nonanalytic one-loop corrections of some physical quantities: the chiral condensate, weak decay constants, Goldstone boson masses, BK and the K + → π+π0 decay amplitude, using partially quenched chiral perturbation theory. Our results for weak decay constants and masses...

Quenched chiral perturbation theory for baryons.

We develop chiral perturbation theory for baryons in quenched QCD. Quenching (the elimination of diagrams containing virtual quark loops) is achieved by extending the Lagrangian method of Bernard and Golterman, and is implemented in a theory where baryons are treated as fixed velocity sources. Our method requires that the octet baryons be represented by a three index tensor rather than by the u...