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Abstract The Precision Proton Spectrometer (PPS) of the CMS and TOTEM experiments collected 107.7 fb -1 in proton-proton (pp) collisions at the LHC at 13 TeV (Run 2). This paper describes the key features of the PPS alignment and optics calibrations, the proton reconstruction procedure, as well as the detector efficiency and the performance of the PPS simulation. The reconstruction and simulation are validated using a sample of (semi)exclusive dilepton events. The performance of PPS has proven the feasibility of continuously operating a near-beam proton spectrometer at a high luminosity hadron collider. 

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

 

A bstract A search is performed for exclusive high-mass γγ → WW and γγ → ZZ production in proton-proton collisions using intact forward protons reconstructed in near-beam detectors, with both weak bosons decaying into boosted and merged jets. The analysis is based on a sample of proton-proton collisions collected by the CMS and TOTEM experiments at $$ \sqrt{s} $$ s = 13 TeV, corresponding to an integrated luminosity of 100 fb − 1 . No excess above the standard model background prediction is observed, and upper limits are set on the pp → pWWp and pp → pZZp cross sections in a fiducial region defined by the diboson invariant mass m (VV) > 1 TeV (with V = W , Z) and proton fractional momentum loss 0 . 04 < ξ < 0 . 20. The results are interpreted as new limits on dimension-6 and dimension-8 anomalous quartic gauge couplings. 

Abstract The production of Z bosons associated with jets is measured in $$\text {p}\text {p}$$ pp collisions at $$\sqrt{s}=13\,\text {Te}\hspace{-.08em}\text {V} $$ s = 13 Te V with data recorded with the CMS experiment at the LHC corresponding to an integrated luminosity of 36.3 $$\,\text {fb}^{-1}$$ fb - 1 . The multiplicity of jets with transverse momentum $$p_{\textrm{T}} > 30\,\text {Ge}\hspace{-.08em}\text {V} $$ p T > 30 Ge V is measured for different regions of the Z boson’s $$p_{\textrm{T}} (\text {Z })$$ p T ( Z ) , from lower than 10 $$\,\text {Ge}\hspace{-.08em}\text {V}$$ Ge V to higher than 100 $$\,\text {Ge}\hspace{-.08em}\text {V}$$ Ge V . The azimuthal correlation $$\varDelta \phi $$ Δ ϕ between the Z boson and the leading jet, as well as the correlations between the two leading jets are measured in three regions of $$p_{\textrm{T}} (\text {Z })$$ p T ( Z ) . The measurements are compared with several predictions at leading and next-to-leading orders, interfaced with parton showers. Predictions based on transverse-momentum dependent parton distributions and corresponding parton showers give a good description of the measurement in the regions where multiple parton interactions and higher jet multiplicities are not important. The effects of multiple parton interactions are shown to be important to correctly describe the measured spectra in the low $$p_{\textrm{T}} (\text {Z })$$ p T ( Z ) regions.