A search for a doubly-charged Higgs boson in pp collisions at √s=7 TeV
European Physical Journal C 72:11 (2012) 1-26
Abstract:
A search for a doubly-charged Higgs boson in pp collisions at √s=7 TeV is presented. The data correspond to an integrated luminosity of 4. 9 fb-1, collected by the CMS experiment at the LHC. The search is performed using events with three or more isolated charged leptons of any flavor, giving sensitivity to the decays of pair-produced triplet components Φ++Φ--, and Φ++Φ- from associated production. No excess is observed compared to the background prediction, and upper limits at the 95 % confidence level are set on the Φ++ production cross section, under specific assumptions on its branching fractions. Lower bounds on the Φ++ mass are reported, providing significantly more stringent constraints than previously published limits. © 2012 CERN for the benefit of the CMS collaboration.First LOFAR observations of gamma-ray binaries
AIP Conference Proceedings 1505 (2012) 374-377
Abstract:
A few binary systems display High Energy (100 MeV-100 GeV) and/or Very High Energy (≳ 100 GeV) gamma-ray emission. These systems also display non-thermal radio emission+that can be resolved with long-baseline radio interferometers, revealing the presence of outflows. It is expected that at very low frequencies the synchrotron radio emission covers larger angular scales than has been reported up to now. Here we present preliminary results of the first deep radio observations of the gamma-ray binary LS I +61 303 with LOFAR, which is sensitive to extended structures on arcsecond to arcminute scales. © 2012 American Institute of Physics.Prototype pipeline for LSST wavefront sensing and reconstruction
Proceedings of SPIE - The International Society for Optical Engineering 8444 (2012)
Abstract:
The Large Synoptic Survey Telescope (LSST) uses an Active Optics System (AOS) to maintain system alignment and surface figure on its three large mirrors. Corrective actions fed to the LSST AOS are determined from 4 curvature based wavefront sensors located on the corners of the inscribed square within the 3.5 degree field of view. Each wavefront sensor is a split detector such that the halves are 1mm on either side of focus. In this paper we describe the development of the Active Optics Pipeline prototype that simulates processing the raw image data from the wavefront sensors through to wavefront estimation on to the active optics corrective actions. We also describe various wavefront estimation algorithms under development for the LSST active optics system. The algorithms proposed are comprised of the Zernike compensation routine which improve the accuracy of the wavefront estimate. Algorithm development has been aided by a bench top optical simulator which we also describe. The current software prototype combines MATLAB modules for image processing, tomographic reconstruction, atmospheric turbulence and Zemax for optical ray-tracing to simulate the closed loop behavior of the LSST AOS. We describe the overall simulation model and results for image processing using simulated images and initial results of the wavefront estimation algorithms. © 2012 SPIE.Status of the KMOS multi-object near-infrared integral field spectrograph
Proceedings of SPIE - The International Society for Optical Engineering 8446 (2012)
Abstract:
KMOS is a multi-object near-infrared integral field spectrograph being built by a consortium of UK and German institutes. We report on the final integration and test phases of KMOS, and its performance verification, prior to commissioning on the ESO VLT later this year. © 2012 SPIE.The opto-mechanical design of HARMONI: A first light integral field spectrograph for the E-ELT
Proceedings of SPIE - The International Society for Optical Engineering 8446 (2012)