[show abstract][hide abstract] ABSTRACT: A first prototype of a scintillator strip-based electromagnetic calorimeter
was built, consisting of 26 layers of tungsten absorber plates interleaved with
planes of 45x10x3 mm3 plastic scintillator strips. Data were collected using a
positron test beam at DESY with momenta between 1 and 6 GeV/c. The prototype's
performance is presented in terms of the linearity and resolution of the energy
measurement. These results represent an important milestone in the development
of highly granular calorimeters using scintillator strip technology. This
technology is being developed for a future linear collider experiment, aiming
at the precise measurement of jet energies using particle flow techniques.
[show abstract][hide abstract] ABSTRACT: Lepton colliders are considered as options to complement and to extend the
physics programme at the Large Hadron Collider. The Compact Linear Collider
(CLIC) is an $e^+e^-$ collider under development aiming at centre-of-mass
energies of up to 3 TeV. For experiments at CLIC, a hadron sampling calorimeter
with tungsten absorber is proposed. Such a calorimeter provides sufficient
depth to contain high-energy showers, while allowing a compact size for the
A fine-grained calorimeter prototype with tungsten absorber plates and
scintillator tiles read out by silicon photomultipliers was built and exposed
to particle beams at CERN. Results obtained with electrons, pions and protons
of momenta up to 10 GeV are presented in terms of energy resolution and shower
shape studies. The results are compared with several GEANT4 simulation models
in order to assess the reliability of the Monte Carlo predictions relevant for
a future experiment at CLIC.
[show abstract][hide abstract] ABSTRACT: Searches for anomalous top quark-antiquark production are presented, based on pp collisions at √s=8 TeV. The data, corresponding to an integrated luminosity of 19.7 fb−1, were collected with the CMS detector at the LHC. The observed ttbar invariant mass spectrum is found to be compatible with the standard model prediction. Limits on the production cross section times branching fraction probe, for the first time, a region of parameter space for certain models of new physics not yet constrained by precision measurements.