Running bumps from stealth bosons

TL;DR

This paper reveals that jet substructure cuts significantly influence the mass distribution of stealth bosons, causing multiple bumps that complicate experimental interpretation and anomaly detection in high-energy physics.

Contribution

It demonstrates the strong correlation between groomed jet mass and substructure variables for stealth bosons, highlighting the impact on resonance searches and interpretation.

Findings

Jet mass distributions are affected by substructure cuts.

Multiple bumps appear at various masses depending on selection.

Interpretation of experimental results requires caution due to these effects.

Abstract

For the "stealth bosons" $S$, light boosted particles with a decay $S \to A A \to q \bar q q \bar q$ into four quarks and reconstructed as a single fat jet, the groomed jet mass has a strong correlation with groomed jet substructure variables. Consequently, the jet mass distribution is strongly affected by the jet substructure selection cuts when applied on the groomed jet. We illustrate this fact by recasting a CMS search for low-mass dijet resonances and show a few representative examples. The mass distributions exhibit narrow and wide bumps at several locations in the 100 - 300 GeV range, between the masses of the daughter particles $A$ and the parent particle $S$, depending on the jet substructure selection. This striking observation introduces several caveats when interpreting and comparing experimental results, for the case of non-standard signatures. The possibility that a single boosted particle decaying hadronically produces multiple bumps, at quite different jet masses, and depending on the event selection, brings the game of anomaly chasing to the next level.