Performance of Same Sign Dimuon Trigger with 2016 pp Collision Data

A same-sign double muon trigger was developed and implemented in LHC Run-2 to search for light pseudoscalar boson pairs produced in the decay of the 125 GeV Higgs boson and resulting in final states with four tau leptons. Each pseudoscalar boson is required to decay into a muon and a charged particle which could either be an electron or a muon or a charged hadron from tau decay, with at least two identified muons in the event which are required to have the same charge sign. The triggering strategy for 13 TeV pp collisions was to keep non-isolated double muon path with low p$\rm_T$ thresholds and implement the same-sign requirement online in order to keep an unprescaled trigger with a significantly reduced rate below 10~Hz. The performance of the same-sign non-isolated double muon trigger in terms of the online charge identification efficiency, vertex filter efficiency and efficiencies of the two muon legs with pp collision data collected by the CMS detector in 2016 is reported in this note.