Dilepton bounds on left-right symmetry at the LHC run II and neutrinoless double beta decay

TL;DR

This paper uses 13 TeV dilepton data from the LHC to set new limits on the mass of the $Z'$ boson in left-right symmetric models, showing dilepton data's importance in constraining new physics.

Contribution

It provides the strongest direct bounds on $Z'$ mass from left-right models to date, considering variable gauge coupling ratios and complementing other experimental searches.

Findings

Excluded $Z'$ masses below 3 TeV for $g_R=g_L$

Excluded $Z'$ masses up to 4 TeV for $g_R \,\sim\, 1$

Dilepton data probes parameter space inaccessible to neutrinoless double beta decay and $lljj$ studies.

Abstract

In the light of the new 13 TeV dilepton data set with $ 3.2\, {\rm fb^{-1}}$ integrated luminosity from the ATLAS collaboration, we derive limits on the $Z^{\prime}$ mass in the context of left-right symmetric models and exploit the complementarity with dijet and $lljj$ data, as well as neutrinoless double beta decay. We keep the ratio of the left- and right-handed gauge coupling free in order to take into account different patterns of left-right symmetry breaking. By combining the dielectron and dimuon data we can exclude $Z^{\prime}$ masses below $3$ TeV for $g_R=g_L$, and for $g_R \sim 1$ we rule out masses up to $\sim 4$ TeV. Those comprise the strongest direct bounds on the $Z^{\prime}$ mass from left-right models up to date. We show that in the usual plane of right-handed neutrino and charged gauge boson mass, dilepton data can probe a region of parameter space inaccessible to neutrinoless double beta decay and $lljj$ studies. Lastly, through the mass relation between $W_R$ and $Z^{\prime}$ we present an indirect bound on the lifetime of neutrinoless double beta decay using dilepton data. Our results prove that the often ignored dilepton data in the context of left-right models actually provide important complementary limits.