Measurement of the total cross section at 8 TeV and the inelastic cross section at 13 TeV at the LHC with the ATLAS detector

New measurements from ATLAS at the LHC are presented on the total cross section at $\sqrt{s}=8$ TeV from elastic scattering using the ALFA sub-detector and on the inelastic cross section at $\sqrt{s}=13$ TeV using the MBTS sub-detector.Comment: Proceedings for Diffraction 2016 conference, 4 pages, 4 figure

Power Law Corrections to Hadronic Event-Shape Variables in e+e−e^{+}e^{-} Annihilation

Measurements of distributions and mean values of the event-shape variables thrust and heavy jet mass in the center-of-mass energy range from 14 GeV up to 172 GeV are analyzed for possible non-perturbative corrections following a power law of the form 1/Q. These corrections are characterized by a single parameter, which can be fitted to the data together with the strong coupling constant. Results on alpha_s are compared to those obtained with hadronization corrections from a Monte Carlo generator

Oriented Event Shapes in Hadronic Z Decays

Using about 4 million events recorded with the ALEPH detector at LEP I, distributions of various event-shape variables are measured as a function of the polar angle of the thrust axis with respect to the e+e- beam direction cos(theta). New calculations which include the event orientation are fitted to the data yielding a measurement of the strong coupling constant alpha_s. The result is compared to that obtained from unoriented event-shape distributions. Preliminary results on alpha_s and on the size of the QCD-corrections to the angular distribution are given

GEANT4 simulation of the testbeam set-up for the ALFA detector

We present the results of a simulation in GEANT4 of a testbeam set-up for the ALFA luminosity detector for ATLAS. In particular, we compare the expected detector resolution with the experimental measurements obtained with a low-energy electron testbeam. The different electromagnetic processes contributing to the energy evolution of the resolution are studied in detail. Finally, the extrapolation of the detector performance under LHC conditions indicates that an ultimate space-point resolution of about 20 mum is possible, fully satisfying the physics requests for luminosity calibration

Basic Considerations on the Overlap Detectors of the ATLAS ALFA system

We discuss the motivation and possible implementation of Overlap Detectors for the relative alignment of the two halves of the ATLAS Roman Pot detectors. We propose a system design and a set of prototype detectors for a proof of principle in a test beam experiment

Prospects for probing the gluon density in protons using heavy quarkonium hadroproduction

We examine carefully bottomonia hadroproduction in proton colliders, especially focusing on the LHC, as a way of probing the gluon density in protons. To this end we develop some previous work, getting quantitative predictions and concluding that our proposal can be useful to perform consistency checks of the parameterization sets of different parton distribution functions.Comment: LaTeX, 14 pages, 6 EPS figure