MgWO4 -A new crystal scintillator
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 608:1 (2009) 107-115
Abstract:
Magnesium tungstate (MgWO4) crystals of ~1 cm3 volume were obtained for the first time using a flux growth technique. The crystal was subjected to comprehensive characterisation that included room-temperature measurements of the transmittance, X-ray luminescence spectra, afterglow under X-ray excitation, relative photoelectron output, energy resolution, non-proportionality of scintillation response to γ-quanta, response to α-particles, and pulse shape for γ-quanta and α-particles. The light output and decay kinetics of MgWO4 were studied over the temperature range 7-305 K. Under X-ray excitation the crystal exhibits an intense luminescence band peaking at a wavelength of 470 nm; the intensity of afterglow after 20 ms is 0.035%. An energy resolution of 9.1% for 662 keV γ-quanta of 137Cs was measured with a small (≈0.9 g) sample of the MgWO4 crystal. The photoelectron output of the MgWO4 crystal scintillator is 35% that of CdWO4 and 27% that of NaI(Tl). The detector showed pulse-shape discrimination ability in measurements with α-particles and γ-quanta, which enabled us to assess the radioactive contamination of the scintillator. The results of these studies demonstrate the prospect of this material for a variety of scintillation applications, including rare event searches. © 2008 Elsevier B.V.Search for a standard model Higgs boson in WH→ℓ vbb̄ in pp̄ collisions at s=1.96TeV
Physical Review Letters 103:10 (2009)
Abstract:
We present a search for a standard model Higgs boson produced in association with a W boson using 2.7fb-1 of integrated luminosity of pp̄ collision data taken at s=1.96TeV. Limits on the Higgs boson production rate are obtained for masses between 100 and 150GeV/c2. Through the use of multivariate techniques, the analysis achieves an observed (expected) 95% confidence level upper limit of 5.6 (4.8) times the theoretically expected production cross section for a standard model Higgs boson with a mass of 115GeV/c2. © 2009 The American Physical Society.Search for a standard model Higgs boson in WH --> lvbb in pp collisions at square root s = 1.96 TeV.
Physical review letters 103:10 (2009) 101802
Abstract:
We present a search for a standard model Higgs boson produced in association with a W boson using 2.7 fb(-1) of integrated luminosity of pp collision data taken at square root s = 1.96 TeV. Limits on the Higgs boson production rate are obtained for masses between 100 and 150 GeV/c(2). Through the use of multivariate techniques, the analysis achieves an observed (expected) 95% confidence level upper limit of 5.6 (4.8) times the theoretically expected production cross section for a standard model Higgs boson with a mass of 115 GeV/c(2).First observation of vector boson pairs in a hadronic final state at the tevatron collider.
Phys Rev Lett 103:9 (2009) 091803
Abstract:
We present the first observation in hadronic collisions of the electroweak production of vector boson pairs (VV, V = W, Z) where one boson decays to a dijet final state. The data correspond to 3.5 fb(-1) of integrated luminosity of pp[over ] collisions at sqrt[s] = 1.96 TeV collected by the CDF II detector at the Fermilab Tevatron. We observe 1516 + or - 239(stat) + or - 144(syst) diboson candidate events and measure a cross section sigma(pp[over ]-->VV + X) of 18.0 + or - 2.8(stat) + or - 2.4(syst) + or -1.1(lumi) pb, in agreement with the expectations of the standard model.Observation of electroweak single top-quark production.
Phys Rev Lett 103:9 (2009) 092002