Tumblers: A Novel Collider Signature for Long-Lived Particles

TL;DR

This paper introduces 'tumblers', a new collider signature involving multiple displaced vertices from long-lived particle decays, and explores their observability and distinguishability at the LHC and future colliders.

Contribution

The paper proposes the 'tumbler' signature, develops methods for reconstructing particle properties, and highlights the importance of timing information for detection.

Findings

Tumblers can be observed at the LHC with enhanced timing information.

Reconstruction techniques for masses and lifetimes are effective for tumbler signatures.

Timing layers significantly improve the discovery prospects of long-lived particles.

Abstract

In this paper, we point out a novel signature of physics beyond the Standard Model which could potentially be observed both at the Large Hadron Collider (LHC) and at future colliders. This signature, which emerges naturally within many proposed extensions of the Standard Model, results from the multiple displaced vertices associated with the successive decays of unstable, long-lived particles along the same decay chain. We call such a sequence of displaced vertices a "tumbler." We examine the prospects for observing tumblers at the LHC and assess the extent to which tumbler signatures can be distinguished from other signatures of new physics which also involve multiple displaced vertices within the same collider event. As part of this analysis, we also develop a procedure for reconstructing the masses and lifetimes of the particles involved in the corresponding decay chains. We find that the prospects for discovering and distinguishing tumblers can be greatly enhanced by exploiting precision timing information such as would be provided by the CMS timing layer at the high-luminosity LHC. Our analysis therefore provides strong additional motivation for continued efforts to improve the timing capabilities of collider detectors at the LHC and beyond.