Optimizing pixel tracklet searches for shorter lifetimes

TL;DR

This paper proposes an optimized pixel tracklet search method with fewer hits and additional soft track requirements to improve sensitivity to shorter-lived dark matter candidates at the LHC.

Contribution

It introduces a new tracklet search strategy optimized for shorter lifetimes, enhancing detection capabilities for nearly-degenerate electroweak multiplet dark matter.

Findings

Enhanced sensitivity to shorter-lived particles.

Effective background suppression with soft track requirement.

Potential extension of existing search reach.

Abstract

Pixel tracklets, disappearing tracks reconstructed with only pixel hits, have proven to be a promising technique in LHC analyses to search for dark matter candidates at the LHC that belong to a nearly-degenerate electroweak multiplet. However, a Pseudo-Dirac electroweak doublet fermion, arguably the most interesting such possibility, has a shorter lifetime and therefore existing tracklet searches are less sensitive in this case. We assess the performance of a tracklet search optimized for shorter lifetimes by requiring only three pixel hits for the tracklet reconstruction, and by demanding an accompanying soft track for suppressing backgrounds. We estimate how far the sensitivity of existing searches can be extended into the region of parameter space with this optimized search.