Mesonic spectroscopy of minimal walking technicolor

Abstract

We investigate the structure and the novel emerging features of the mesonic nonsinglet spectrum of the minimal walking technicolor theory. Precision measurements in the nonsinglet pseudoscalar and vector channels are compared to the expectations for an IR-conformal field theory and a QCD-like theory. Our results favor a scenario in which minimal walking technicolor is (almost) conformal in the infrared, while spontaneous chiral symmetry breaking seems less plausible.

Large mass hierarchies from strongly-coupled dynamics

“…At large L, the leading behaviour with M 0 of the previous equation predicts constant mass ratios as m is varied [33][34][35]. Equipped with these considerations, in subsections 2.4 and 2.5 we present lattice results for the ratio R ≡ M T /M 0 with M T and M 0 respectively the mass of the tensor and scalar, determined by probing the theory with glueball-like operators.…”

“…A vast body of literature exists on its spectrum [33][34][35][36][37][38][39][40][41][42], on the running of its coupling [43][44][45][46][47] and on the anomalous dimension of its chiral condensate [48][49][50][51][52]. From a phenomenological point of view, this theory is likely to be of limited relevance, since the anomalous dimension of the condensate is small.…”

“…The dimensionless variable describing scaling with m and L is then x = Lm 1/∆ . From the Widom form of the effective action, one can derive the scaling law [34,35,48,82] …”

Lattice studies of quantum chromodynamics-like theories with many fermionic degrees of freedom

“…Then, the mass is the relevant perturbation and all the statistical mechanics machinery for scaling near a critical point can be employed. This gives g m (g 2 ) for SU (2) in a wide variety of ways [51][52][53]. It turns out to be small, less than about 0.5, and consistent with perturbation theory, equation (1.6).…”

“…Many groups (a representative list includes [48][49][50][51][52][53]) have studied N f = 2 flavours of adjoint representation fermions in SU (2). All studies to date use Wilson-type quarks.…”