Hayrapetyan, A.Tumasyan, A.Adam, W.Andrejkovic, J. W.Bergauer, T.Chatterjee, S.Damanakis, K.2025-03-232025-03-2320240031-90071079-7114https://doi.org/10.1103/PhysRevLett.132.041802https://hdl.handle.net/11486/5468A search for dark matter in events with a displaced nonresonant muon pair and missing transverse momentum is presented. The analysis is performed using an integrated luminosity of 138 fb-1 of protonproton (pp) collision data at a center -of -mass energy of 13 TeV produced by the LHC in 2016-2018. No significant excess over the predicted backgrounds is observed. Upper limits are set on the product of the inelastic dark matter production cross section sigma(pp -> A0 -> chi 1 chi 2) and the decay branching fraction B(chi 2 -> chi 1 mu thorn mu-), where A0 is a dark photon and chi 1 and chi 2 are states in the dark sector with near mass degeneracy. This is the first dedicated collider search for inelastic dark matter.eninfo:eu-repo/semantics/openAccessArticle132410.1103/PhysRevLett.132.041802389493502-s2.0-85184280909Q1WOS:001190906300004Q1