Search for central exclusive production of top quark pairs in proton-proton collisions at √s = 13 TeV with tagged protons

A bstract A search for the central exclusive production of top quark-antiquark pairs ( tt̄ t t ¯ ) is performed for the first time using proton-tagged events in proton-proton collisions at the LHC at a centre-of-mass energy of 13 TeV. The data correspond to an integrated luminosity of 29.4 fb − 1 . The tt̄ t t ¯ decay products are reconstructed using the central CMS detector, while forward protons are measured in the CMS-TOTEM precision proton spectrometer. An observed (expected) upper bound on the production cross section of 0.59 (1.14) pb is set at 95% confidence level, for collisions of protons with fractional momentum losses between 2 and 20%.