Observation of deflection of a beam of multi-GeV electrons by a thin crystal

We report on an experiment performing channeling and volume reflection of a high-energy electron beam using a quasimosaic, bent silicon (111) crystal at the End Station A Test Beam at SLAC. The experiment uses beams of 3.35 and 6.3 GeV. In the channeling orientation, deflections of the beam of 400  μrad for both energies with about 22% efficiency are observed, while in the volume-reflection orientation, deflection of the beam by 120  μrad at 3.35 GeV and by 80  μrad at 6.3 GeV is observed with 86%–95% efficiency. Quantitative measurements of the channeling efficiency, surface transmission, and dechanneling length are taken. These are the first quantitative measurements of channeling and volume reflection using a primary beam of multi-GeV electrons

Measurement of shower development and its Molière radius with a four-plane LumiCal test set-up

A prototype of a luminometer, designed for a future $e^+e^-$ collider detector, and consisting at present of a four-plane module, was tested in the CERN PS accelerator T9 beam. The objective of this beam test was to demonstrate a multi-plane tungsten/silicon operation, to study the development of the electromagnetic shower and to compare it with MC simulations. The Molière radius has been determined to be 24.0 ± 0.6 (stat.) ± 1.5 (syst.) mm using a parametrization of the shower shape. Very good agreement was found between data and a detailed Geant4 simulation.A prototype of a luminometer, designed for a future e+e- collider detector, and consisting at present of a four-plane module, was tested in the CERN PS accelerator T9 beam. The objective of this beam test was to demonstrate a multi-plane tungsten/silicon operation, to study the development of the electromagnetic shower and to compare it with MC simulations. The Moli\`ere radius has been determined to be 24.0 +/- 0.6 (stat.) +/- 1.5 (syst.) mm using a parametrization of the shower shape. Very good agreement was found between data and a detailed Geant4 simulation

Physics at the CLIC e+e- Linear Collider -- Input to the Snowmass process 2013

Updated the author list, updated Higgs results and small changes in the text of the Higgs section, updated results on composite Higgs bosons, added and updated references. Final submission for the Snowmass proceedingsThis paper summarizes the physics potential of the CLIC high-energy e+e- linear collider. It provides input to the Snowmass 2013 process for the energy-frontier working groups on The Higgs Boson (HE1), Precision Study of Electroweak Interactions (HE2), Fully Understanding the Top Quark (HE3), as well as The Path Beyond the Standard Model -- New Particles, Forces, and Dimensions (HE4). It is accompanied by a paper describing the CLIC accelerator study, submitted to the Frontier Capabilities group of the Snowmass process