Large mass hierarchies from strongly-coupled dynamics
Résumé
Motivated by the absence of signals of new physics at the LHC, which seems to imply the presence of large mass hierarchies, we investigate the theoretical possibility that these could arise dynamically in new strongly-coupled gauge theories extending the standard model of particle physics. To this purpose, we study lattice data on non-Abelian gauge theories in the (near-)conformal regime---specifically, $\mathrm{SU}(2)$ with $N_{\mathrm{f}}=1$ and $2$ dynamical fermion flavours in the adjoint representation. We focus our attention on the ratio $R$ between the masses of the lightest spin-2 and spin-0 resonances, and draw comparisons with a simple toy model in the context of gauge/gravity dualities. For models in which large anomalous dimensions arise dynamically, we show indications that this mass ratio can be large, with $R > 5$. Moreover, our results suggest that $R$ might be related to universal properties of the IR fixed point. Our findings provide an interesting step towards understanding large mass ratios in the non-perturbative regime of quantum field theories with (near) IR conformal behaviour.
Mots clés
mass: hierarchy
new physics
Higgs particle: composite
strong interaction: new interaction
gauge field theory: nonabelian
gravitation: duality
gauge field theory: SU(2)
fermion: flavor
fermion: Wilson
flavor: 1
flavor: 2
fixed point: infrared
mass ratio
resonance: mass
field theory: conformal
anomalous dimension
nonperturbative
CERN LHC Coll
toy model
lattice field theory
numerical calculations