Proton reconstruction with the TOTEM Roman pot detectors for high-B* LHC data

Abstract

The TOTEM Roman pot detectors are used to reconstruct the transverse momentum of scattered protons and to estimate the transverse location of the primary interaction. This paper presents new methods of track reconstruction, measurements of strip-level detection efficiencies, cross-checks of the LHC beam optics, and detector alignment techniques, along with their application in the selection of signal collision events. The track reconstruction is performed by exploiting hit cluster information through a novel method using a common polygonal area in the intercept-slope plane. The technique is applied in the relative alignment of detector layers with um precision. A tag-and-probe method is used to extract strip-level detection efficiencies. The alignment of the Roman pot system is performed through time-dependent adjustments, resulting in a position accuracy of 3 um in the horizontal and 60 um in the vertical directions. The goal is to provide an optimal reconstruction tool for central exclusive physics analyses based on the high-B* data-taking period at V¯(s) = 13 TeV in 2018.