Hayrapetyan A.Makarenko V.Tumasyan A.Adam W.Andrejkovic J.W.Benato L.Snigirev A.2026-03-102026-03-1020262470-00102470-0029https://doi.org/10.1103/7ldn-snznhttps://hdl.handle.net/20.500.13091/13091A search for long-lived particles originating from the decay of b hadrons produced in proton-proton collisions with a center-of-mass energy of 13 TeV at the LHC is presented. The analysis is performed on a dataset recorded in 2018, corresponding to an integrated luminosity of 41.6 fb-1. Interactions of the long-lived particles in the CMS endcap muon system would create hadronic or electromagnetic showers, producing clusters of detector hits. Selected events contain at least one such high-multiplicity cluster in the muon endcaps and require the presence of a displaced muon. The most stringent upper limits to date on the branching fraction B(B - ΚΦ), where the long-lived particle Φ decays to a pair of hadrons, are obtained for Φ masses of 0.3-3.0 GeV and Φ mean proper decay lengths in the range of 1-500 cm. © 2026 CERN, for the CMS Collaborationeninfo:eu-repo/semantics/openAccessArticle10.1103/7ldn-snzn2-s2.0-105030632370