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T: Fachverband Teilchenphysik
T 11: QCD / Partonstruktur
T 11.7: Talk
Monday, March 19, 2018, 17:30–17:45, Z6 - SR 1.002
Determination of the total cross section and the ρ-parameter in proton–proton collisions at the LHC at √s = 13 TeV from elastic scattering using the ALFA sub-detector of ATLAS — •Christian Heinz, Hasko Stenzel, and Michael Düren — 2. Physikalisches Institut, Universtät Gießen
The ALFA (Absolute Luminosity for ATLAS) Roman Pot detector system is part of the forward instrumentation of ATLAS located about 240 m downstream of the interaction point in the LHC tunnel. ALFA consists of scintillating fibre trackers housed in vertical Roman Pots which enable the measurement of elastic proton-proton scattering at small scattering angles. In 2016, data were recorded at a centre-of-mass energy of √s = 13 TeV during several fills with special beam optics of the LHC with β* = 2.5 km 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 including the Coulomb nuclear interference region. In this talk a progress report of the determination of the total cross section, the nuclear slope of the elastic cross section and of ρ = ℜ fel(t → 0)/ℑ fel(t → 0) at small |t| is given.