Browsing by Author "Zich, J."

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Proton Reconstruction With the TOTEM Roman Pot Detectors for High-Β* LHC Data
(IOP Publishing Ltd, 2025) Hayrapetyan, A.; Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Benato, L.; Bergauer, T.; Zich, J.
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 mu m 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 mu m in the horizontal and 60 mu m in the vertical directions. The goal is to provide an optimal reconstruction tool for central exclusive physics analyses based on the high-beta* data-taking period at root s = 13 TeV in 2018.
Citation - WoS: 5
Citation - Scopus: 11
Search for High-Mass Exclusive Diphoton Production With Tagged Protons in Proton-Proton Collisions at √s=13 Tev
(Amer Physical Soc, 2024) Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Zich, J.
A search is presented for high-mass exclusive diphoton production via photon-photon fusion in proton-proton collisions at root s = 13 TeV in events where both protons survive the interaction. The analysis utilizes data corresponding to an integrated luminosity of 103 fb(-1) collected in 2016-2018 with the central CMS detector and the CMS and TOTEM precision proton spectrometer (PPS). Events that have two photons with high transverse momenta (p(T)(gamma) > 100 GeV), back-to-back in azimuth, and with a large diphoton invariant mass (m(gamma gamma) > 350 GeV) are selected. To remove the dominant inclusive diphoton backgrounds, the kinematic properties of the protons detected in PPS are required to match those of the central diphoton system. Only events having opposite-side forward protons detected with a fractional momentum loss between 0.035 and 0.15 (0.18) for the detectors on the negative (positive) side of CMS are considered. One exclusive diphoton candidate is observed for an expected background of 1.1 events. Limits at 95% confidence level are derived for the four-photon anomalous coupling parameters |zeta(1)| < 0.073 TeV-4 and |zeta(2)| < 0.15 TeV-4, using an effective field theory. Additionally, upper limits are placed on the production of axionlike particles with coupling strength to photons f(-1) that varies from 0.03 TeV-1 to 1 TeV-1 over the mass range from 500 to 2000 GeV.