Search for long-lived particles decaying into displaced jets

An inclusive search for long-lived particles decaying into jets is presented. The search uses a data sample corresponding to an integrated luminosity of $132~\mathrm{fb}^{-1}$ from proton-proton collisions at a center-of-mass energy of $13~\mathrm{TeV}$, collected with the CMS detector at the LHC in 2016, 2017, and 2018. The analysis examines the distinctive topology of displaced tracks and displaced vertices within a dijet system. For a simplified model, where pair-produced long-lived neutral particles decay into quark-antiquark pairs, pair production cross sections larger than $0.07~\mathrm{fb}$ are excluded at $95\%$ confidence level for long-lived particle masses larger than $500~\mathrm{GeV}$ and mean proper decay lengths between 2 and $250~\mathrm{mm}$. For a model where the standard model Higgs boson decays to two long-lived scalars and then each scalar decays to a quark-antiquark pair, branching fractions larger than $1\%$ can be excluded for mean proper decay lengths between $1~\mathrm{mm}$ and $1~\mathrm{m}$. A group of supersymmetry models with pair-produced long-lived gluinos or top squarks decaying into different final-state topologies containing displaced jets is also tested. Gluino masses up to $2500~\mathrm{GeV}$ and top squark masses up to $1600~\mathrm{GeV}$ are excluded for mean proper decay lengths between 3 and $300~\mathrm{mm}$. The best mass bounds reach $2600~\mathrm{GeV}$ for long-lived gluinos and $1800~\mathrm{GeV}$ for long-lived top squarks. These are currently the most restrictive limits on these models.