Abstract
We investigate chiral and conformal properties of the lattice QCD with eight flavors () through meson spectrum using the highly improved staggered quark (HISQ) action. We also compare our results with those of and which we study on the same systematics. We find that the decay constant of the pseudoscalar meson “pion” is nonzero, with its mass consistent with zero, both in the chiral limit extrapolation of the chiral perturbation theory. We also measure other quantities which we find are in accord with the data results: The meson mass is consistent with nonzero in the chiral limit, and so is the chiral condensate, with its value neatly coinciding with that from the Gell-Mann-Oakes-Renner relation in the chiral limit. Thus, our data for the QCD are consistent with the spontaneously broken chiral symmetry. Remarkably enough, while the data near the chiral limit are well described by the chiral perturbation theory, those for the relatively large fermion bare mass away from the chiral limit actually exhibit a finite-size hyperscaling relation, suggesting a large anomalous dimension . This implies that there exists a remnant of the infrared conformality, and suggests that a typical technicolor (“one-family model”) as modeled by the QCD can be a walking technicolor theory having an approximate scale invariance with large anomalous dimension .
21 More- Received 27 February 2013
DOI:https://doi.org/10.1103/PhysRevD.87.094511
© 2013 American Physical Society