Large mass hierarchies from strongly-coupled dynamics

TL;DR

This paper explores how large mass hierarchies between resonances can emerge dynamically in strongly-coupled gauge theories, using lattice data and gauge/gravity dualities, potentially explaining new physics signals at the TeV scale.

Contribution

It demonstrates that large mass ratios in strongly-coupled theories with near-conformal behavior can arise due to large anomalous dimensions, providing a possible dynamical origin for TeV-scale resonance hierarchies.

Findings

Mass ratio R can exceed 5 in models with large anomalous dimensions.

Large mass ratios may be related to universal properties of IR fixed points.

Results suggest a dynamical explanation for large hierarchies in new resonances.

Abstract

Besides the Higgs particle discovered in 2012, with mass 125 GeV, recent LHC data show tentative signals for new resonances in diboson as well as diphoton searches at high center-of-mass energies (2 TeV and 750 GeV, respectively). If these signals are confirmed (or other new resonances are discovered at the TeV scale), the large hierarchies between masses of new bosons require a dynamical explanation. Motivated by these tentative signals of new physics, we investigate the theoretical possibility that large hierarchies in the masses of glueballs could arise dynamically in new strongly-coupled gauge theories extending the standard model of particle physics. We study lattice data on non-Abelian gauge theories in the (near-)conformal regime as well as a simple toy model in the context of gauge/gravity dualities. We focus our attention on the ratio $R$ between the mass of the lightest spin-2 and spin-0 resonances, that for technical reasons is a particularly convenient and clean observable to study. For models in which (non-perturbative) 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.