Measurement of the total cross section and [Formula omitted]-parameter from elastic scattering in pp collisions at [Formula omitted] TeV with the ATLAS detector

• Published in: The European physical journal. C, Particles and fields Vol. 83; no. 5
• Main Authors: Aad, G, Abbott, B, Abbott, D. C, Abeling, K, Abidi, S. H, Aboulhorma, A, Abramowicz, H
• Format: Journal Article
• Language: English
• Published: Springer 01.05.2023
• Subjects: Detectors
• ISSN: 1434-6044; 1434-6052
• DOI: 10.1140/epjc/s10052-023-11436-8

In a special run of the LHC with [Formula omitted] km, proton-proton elastic-scattering events were recorded at [Formula omitted] TeV with an integrated luminosity of [Formula omitted] using the ALFA subdetector of ATLAS in 2016. The elastic cross section was measured differentially in the Mandelstam t variable in the range from [Formula omitted] GeV [Formula omitted] to [Formula omitted] GeV [Formula omitted] using 6.9 million elastic-scattering candidates. This paper presents measurements of the total cross section [Formula omitted], parameters of the nuclear slope, and the [Formula omitted]-parameter defined as the ratio of the real part to the imaginary part of the elastic-scattering amplitude in the limit [Formula omitted]. These parameters are determined from a fit to the differential elastic cross section using the optical theorem and different parameterizations of the t-dependence. The results for [Formula omitted] and [Formula omitted] are [sigma]tot(pp[right arrow]X)=104.7±1.1mb,[rho]=0.098±0.011.The uncertainty in [Formula omitted] is dominated by the luminosity measurement, and in [Formula omitted] by imperfect knowledge of the detector alignment and by modelling of the nuclear amplitude.