CMS-PAS-EXO-20-003

CMS-PAS-EXO-20-003
Search for Higgs boson decays into long-lived particles in associated Z boson production
CMS Collaboration
May 2021

Abstract: We present a search for long-lived particles (LLPs) produced in association with a Z boson. The search is performed with data from 13 TeV proton-proton collisions recorded by the CMS experiment during 2016-2018, corresponding to an integrated luminosity of 117 fb$^{-1}$. The LLPs are assumed to decay into a pair of standard model fermions inside the tracker volume, which results in displaced jets. A trigger and selections based on Z boson decays to electron or muon pairs provide sensitivity to light (15 GeV or less) LLPs, which have up to now been difficult to access. Decays of LLPs are selected by requiring the presence of displaced jets which are identified using information from the CMS tracking system. The results are interpreted in the context of exotic decays of the Higgs boson to LLPs ($\mathrm{H} \to \mathrm{S}\mathrm{S}$). The search is sensitive to branching fractions $\mathcal{B}( \mathrm{H} \to \mathrm{S}\mathrm{S})$ of 4-5% (less than 20%) for LLP masses of 40 (15) GeV and mean proper decay lengths of 10-100 mm (10-50 mm).
Links: CDS record (PDF) ; inSPIRE record ; Physics Briefing ; CADI line (restricted) ; These preliminary results are superseded in this paper, JHEP 03 (2022) 160. The superseded preliminary plots can be found here.

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