Semi-visible emerging jets

TL;DR

This paper introduces semi-visible emerging jets (SVEJ), a new dark-shower signature that bridges semi-visible and emerging jets, with optimized detection strategies for specific dark pion lifetimes, enhancing sensitivity in collider searches.

Contribution

It proposes the SVEJ signature, outlines an analysis strategy for dark pion lifetimes around 10 mm, and reinterprets existing LLP searches to improve detection sensitivity.

Findings

Sensitivity to cross sections of about 0.1 fb for 10 mm dark pion lifetimes.

SVEJ signatures interpolate between semi-visible and emerging jets regimes.

Reinterpretation of existing LLP searches extends detection reach.

Abstract

We propose a new class of dark-shower signatures in Standard Model extensions featuring Hidden Valleys or dark sectors coupled through an s-channel mediator. In this framework, unstable dark pions appear as long-lived particles (LLPs), with their lifetimes treated as free parameters. The resulting signatures, which we term semi-visible emerging jets (SVEJ), continuously interpolate between the established semi-visible and emerging jet regimes. We outline an analysis strategy optimized for dark pion lifetimes of order $\mathcal{O}(10)$ mm, and reinterpret existing LLP searches targeting lifetimes of $\mathcal{O}(100)$-$\mathcal{O}(1000)$ mm. Our proposed SVEJ search, exploiting the current ATLAS emerging-jet trigger, achieves sensitivity to cross sections of $\mathcal{O}(0.1)$ fb for lifetimes around $\mathcal{O}(10)$ mm. Finally, we advocate a more detailed study, including hadronization uncertainties and detector-level effects.