European Physical Journal C, vol.83, no.9, 2023 (SCI-Expanded)
A generic search is presented for the associated production of a Z boson or a photon with an additional unspecified massive particle X, pp → pp + Z / γ + X , in proton-tagged events from proton–proton collisions at s=13TeV , recorded in 2017 with the CMS detector and the CMS-TOTEM precision proton spectrometer. The missing mass spectrum is analysed in the 600–1600 GeV range and a fit is performed to search for possible deviations from the background expectation. No significant excess in data with respect to the background predictions has been observed. Model-independent upper limits on the visible production cross section of pp → pp + Z / γ + X are set.