CMS-PAS-EXO-19-013

CMS-PAS-EXO-19-013
Search for long-lived particles decaying to jets with displaced vertices
CMS Collaboration
September 2020

Abstract: We report the results of a search for long-lived particles produced in pairs in proton-proton collisions at the LHC operating at a center-of-mass energy of $\sqrt{s}= $ 13 TeV. The data were collected by the CMS detector during the full Run 2 data taking period from 2015 through 2018, corresponding to a total integrated luminosity of 140 fb$^{-1}$. This search targets long-lived particles with a mean proper decay length between 0.1 and 100 mm that each decay into at least two quarks. The signature is a pair of displaced vertices each formed from many tracks. This search extends a previous CMS search using the 2015 and 2016 dataset, with improvements in background rejection, background estimation techniques, as well as uncertainty estimation. By requiring two reconstructed vertices inside the beam pipe, this search has particularly high sensitivity to decay lengths below 20 mm, which complements similar long-lived search strategies that are less sensitive to such short decay lengths. Results are compared with $R$-parity violating supersymmetry models that predict pair-produced long-lived particles, each decaying into multijet or dijet final states. No events are observed with two reconstructed high-track-multiplicity vertices. For models of long-lived pair-produced neutralinos, gluinos, and top squarks, pair-production cross sections larger than 0.08 fb are excluded at 95% confidence level for masses between 800 and 3000 GeV and mean proper decay lengths between 1 and 25 mm.
Links: CDS record (PDF) ; inSPIRE record ; CADI line (restricted) ; These preliminary results are superseded in this paper, Submitted to PRD. The superseded preliminary plots can be found here.

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