Searching for Displaced Higgs Decays

TL;DR

This paper investigates a simplified model of Higgs decays into long-lived scalars, proposing new search strategies to detect such displaced decays and setting bounds on Higgs branching ratios.

Contribution

It introduces novel tracker search strategies for displaced Higgs decays and provides sensitivity projections for Run II at 13 TeV.

Findings

Bounds for displaced Higgs decays below 10 cm are established from Run I data.

New search strategies can probe Higgs branching ratios down to 7×10⁻⁴ with 20 fb⁻¹ at 13 TeV.

Projected sensitivities for Run II are presented.

Abstract

We study a simplified model of the SM Higgs boson decaying to a degenerate pair of scalars which travel a macroscopic distance before decaying to SM particles. This is the leading signal for many well-motivated solutions to the hierarchy problem that do not propose additional light colored particles. Bounds for displaced Higgs decays below $10$ cm are found by recasting existing tracker searches from Run I. New tracker search strategies, sensitive to the characteristics of these models and similar decays, are proposed with sensitivities projected for Run II at $\sqrt{s} = 13 $ TeV. With 20 fb$^{-1}$ of data, we find that Higgs branching ratios down to $7 \times 10^{-4}$ can be probed for centimeter decay lengths.