A search for new physics in central exclusive production using the missing mass technique with the CMS detector and the CMS-TOTEM precision proton spectrometer

A generic search is presented for the associated production of a Z boson or a photon with an additional unspecified massive particle X, $\text{pp}\to \text{pp}+\text{Z}/\gamma +\text{X}$ , in proton-tagged events from proton–proton collisions at $\sqrt{s}=13\phantom{\rule{0.166667em}{0ex}}\text{TeV}$ , 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 $\text{pp}\to \text{pp}+\text{Z}/\gamma +\text{X}$ are set.