Neutrino Jets from High-Mass $W_R$ Gauge Bosons in TeV-Scale Left-Right Symmetric Models

Abstract

We re-examine the discovery potential at hadron colliders of high-mass right-handed (RH) gauge bosons $W_R$ - an inherent ingredient of Left-Right Symmetric Models (LRSM). We focus on the regime where the $W_R$ is very heavy compared to the heavy Majorana neutrino $N$, and investigate an alternative signature for $W_R\to N$ decays. The produced neutrinos are highly boosted in this mass regime. Subsequently, their decays via off-shell $W_R$ bosons to jets, i.e., $N\to {\ell }^{\pm }jj$ are highly collimated, forming a single neutrino jet $(j_N)$. The final-state collider signature is then ${\ell }^{\pm }{j}_N$, instead of the widely studied ${\ell }^{\pm }{\ell }^{\pm }jj$. Present search strategies are not sensitive to this hierarchical mass regime due to the breakdown of the collider signature definition. We take into account QCD corrections beyond next-to-leading order (NLO) that are important for high-mass Drell-Yan processes at the 13 TeV Large Hadron Collider (LHC). For the first time, we evaluate $W_R$ production at NLO with threshold resummation at next-to-next-to-leading logarithm (NNLL) matched to the threshold-improved parton distributions. With these improvements, we find that a $W_R$ of mass $M_{W_R}=3(4)[5]$ TeV and mass ratio of $(m_N/M_{W_R})<0.1$ can be discovered with a $5-6\ddot{I}ƒ$ statistical significance at 13 TeV after $10(100)[2000]{\text{fb}}^{-1}$ of data. Extending the analysis to the hypothetical 100 TeV Very Large Hadron Collider (VLHC), $5\ddot{I}ƒ$ can be obtained for $W_R$ masses up to $M_{W_R}=15(30)$ with approximately $100{\text{fb}}^{-1}(10{\text{ab}}^{-1})$.

v2, journal version. PRD (2016). Results unchanged