Münster 2017 – scientific programme

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T: Fachverband Teilchenphysik

T 6: QCD

T 6.7: Talk

Monday, March 27, 2017, 18:15–18:30, VSH 10

Determination of the total cross section in proton–proton collisions at the LHC at √s = 8 from elastic scattering using the ALFA sub-detector of ATLAS — •Christian Heinz, Hasko Stenzel, and Michael Düren — Universität Gießen, 2. Physikalisches Institut

The ALFA (Absolute Luminosity for ATLAS) Roman Pot detector system is part of the forward instrumentation of ATLAS located about 240 m away from the interaction point in the LHC tunnel in both directions. ALFA consists of a scintillating fibre tracker housed in vertical Roman Pots which enables the measurement of elastic proton-proton scattering at small scattering angles. In 2012 data were recorded at a centre-of-mass energy of √s = 8 TeV during a fill with special beam optics of the LHC with β^* = 90 m and parallel-to-point focusing.

The four-momentum transfer t is measured for elastically scattered protons and used to extract the differential elastic cross section. The differential elastic cross section is fitted at small |t| using the optical theorem. In this talk the published results of the determination of the total cross section and of the slope of the elastic cross section is reported.