Detecting a Boosted Diboson Resonance

TL;DR

This paper develops specialized algorithms to detect highly boosted scalar particles decaying into dibosons at the LHC, focusing on scenarios where the scalar is produced via decay of heavier particles, leading to merged jet signatures.

Contribution

It introduces new algorithms for tagging boosted diboson signals in complex jet structures, improving detection sensitivity in challenging mass ranges.

Findings

Enhanced sensitivity to boosted scalar resonances at the LHC.

Effective identification of merged jet signatures from boosted dibosons.

Potential to explore previously unconstrained mass regions.

Abstract

New light scalar particles in the mass range of hundreds of GeV, decaying into a pair of $W/Z$ bosons can appear in several extensions of the SM. The focus of collider studies for such a scalar is often on its direct production, where the scalar is typically only mildly boosted. The observed $W/Z$ are therefore well-separated, allowing analyses for the scalar resonance in a standard fashion as a low-mass diboson resonance. In this work we instead focus on the scenario where the direct production of the scalar is suppressed, and it is rather produced via the decay of a significantly heavier (a few TeV mass) new particle, in conjunction with SM particles. Such a process results in the scalar being highly boosted, rendering the $W/Z$'s from its decay merged. The final state in such a decay is a "fat" jet, which can be either four-pronged (for fully hadronic $W/Z$ decays), or may be like a $W/Z$ jet, but with leptons buried inside (if one of the $W/Z$ decays leptonically). In addition, this fat jet has a jet mass that can be quite different from that of the $W/Z$/Higgs/top quark-induced jet, and may be missed by existing searches. In this work, we develop dedicated algorithms for tagging such multi-layered "boosted dibosons" at the LHC. As a concrete application, we discuss an extension of the standard warped extra-dimensional framework where such a light scalar can arise. We demonstrate that the use of these algorithms gives sensitivity in mass ranges that are otherwise poorly constrained.