# CMS Hardware Track Trigger: New Opportunities for Long-Lived Particle Searches at the HL-LHC

## TL;DR

The paper explores how the upgraded CMS hardware track trigger at the HL-LHC can enable new physics searches, particularly for long-lived particles, by utilizing detailed track information in the first-level trigger.

## Contribution

It demonstrates the potential of the CMS hardware track trigger for innovative long-lived particle searches using a simple simulation approach.

## Key findings

- Track trigger can identify long-lived particles with millimeter-scale decay lengths.
- Potential to discover rare Higgs decays into new particles.
- Enhanced physics reach beyond traditional trigger capabilities.

## Abstract

The planned upgrade of the CMS detector for the High Luminosity LHC allows to find tracks in the silicon tracker for every single LHC collision and use them in the first level (hardware) trigger decision. So far, studies by CMS collaboration concentrated on the maintaining the overall trigger performance in the punishing pile up environment. We argue that the potential capabilities of the track trigger are much wider, and may offer groundbreaking opportunities for new physics searches. As an example, and to facilitate community discussion, we use a simple toy simulation to study rare Higgs decays into new particles with lifetime of order of a few mm.