CERN Document Server

Top production measurements with ATLAS: probes at the frontier of the Standard Model

Measurements of the inclusive and differential cross-sections of top-quark production in proton-proton collisions at centre-of-mass energies of 8 and 13 TeV with the ATLAS detector at the Large Hadron Collider are presented. The inclusive measurements reach high precision and are compared to the most precise available theoretical calculations. Differential measurements of the kinematic properties of top-quark events and of top quark pair production associated with photons are also discussed. These measurements, including results using highly boosted top quarks, probe our understanding of top-quark production in the TeV regime. The results are compared to predictions of Monte Carlo generators implementing NLO matrix elements matched with parton showers and NNLO QCD theory calculations and allow for an alternative measurement of the top quark mass.</p

Fast and Precise Beam Energy Measurement using Compton Backscattering at e+e- Colliders

The report describes a method for a fast and precise beam energy measurement in the beam energy range 0.5-2 GeV and its application at various e+e- colliders. Low-energy laser photons interact head-on with the electron or positron beam and produce Compton backscattered photons whose energy is precisely measured by HPGe detector. The method allows measuring the beam energy with relative accuracy of ∼2-5.10-5. The method was successfully applied at VEPP-4M, VEPP-3, VEPP-2000 (BINP, Russia) and BEPC-II (IHEP, China)

Design study of CEPC Alternating Magnetic Field Booster

The CEPC is a next generation circular e+e- collider proposed by China. The design of the full energy booster ring of the CEPC is especially challenging. The ejected beam energy is 120 GeV, but that of the injected beam is only 6 GeV. In a conventional approach, the low magnetic field of the main dipole magnets creates problems. We propose operating the booster ring as a large wiggler at low beam energies and as a normal ring at high energies to avoid the problem of very low dipole magnet fields

Application of a Low-Energy Electron Beam as a Tool for ultrashort bunch length measurement in circular machines

A new diagnostic device designed for non-destructive ultrashort bunch length measurement is described. The operating principle of the device and the measuring technique are described. The possible scheme of arrangement of the device elements are described. The results of simulations of EBP application for different beams under investigation are presented. The quality requirements of the low energy testing beam are considered and resolving detector ability is determined

Measurements of the $C\!P$-violating phase $\phi_{s}$ at LHCb

The measurement of the mixing-induced $C\!P$-violating phase $\phi_{s}$ in the $B^{0}_{s}-\bar{B}^{0}_{s}$ system is one of the key goals of the LHCb experiment. It has been measured at the LHCb collaboration exploiting the Run~I data set and using several decay channels. In particular, the most recent Run~I result has been obtained analyzing $B^{0}_{s}\to J/\psi K^{+}K^{-}$ candidates in the mass region above the $\phi(1020)$ resonance. Despite the large improvements in the sensitivity of $\phi_{s}$ during the last decade, the precision is still limited by the available statistics

Distribution of All CERN Users by Location of Institute on 24 January 2018

Distribution of All CERN Users by Location of Institute on 24 January 201

IT Lightning Talks: session #15

Last year I went to Rails Girls workshop and today I want to tell you how it looked. And no, I was not kicked out because I'm a man - I actually had a great time

Measurement of tau lepton decays to kaons at OPAL

Repository Dashboard
Do you manage CERN Document Server? Access insider analytics, issue reports and manage access to outputs from your repository in the CORE Repository Dashboard!