Matt Hollingsworth

Results are presented from searches for the standard model Higgs boson in proton-proton collisions at sqrt(s) = 7 and 8 TeV in the Compact Muon Solenoid experiment at the LHC, using data samples corresponding to integrated luminosities of up to 5.1 inverse femtobarns at 7 TeV and 5.3 inverse femtobarns at 8 TeV. The search is performed in five decay modes: gamma gamma, ZZ, WW, tau tau, and b b-bar. An excess of events is observed above the expected background, with a local significance of 5.0… Show more

Results are presented from searches for the standard model Higgs boson in proton-proton collisions at sqrt(s) = 7 and 8 TeV in the Compact Muon Solenoid experiment at the LHC, using data samples corresponding to integrated luminosities of up to 5.1 inverse femtobarns at 7 TeV and 5.3 inverse femtobarns at 8 TeV. The search is performed in five decay modes: gamma gamma, ZZ, WW, tau tau, and b b-bar. An excess of events is observed above the expected background, with a local significance of 5.0 standard deviations, at a mass near 125 GeV, signalling the production of a new particle. The expected significance for a standard model Higgs boson of that mass is 5.8 standard deviations. The excess is most significant in the two decay modes with the best mass resolution, gamma gamma and ZZ; a fit to these signals gives a mass of 125.3 +/- 0.4 (stat.) +/- 0.5 (syst.) GeV. The decay to two photons indicates that the new particle is a boson with spin different from one. Show less

We describe the results from a beam test of a telescope consisting of three planes of single-crystal, diamond pixel detectors. This telescope is a prototype for a proposed small-angle luminosity monitor, the Pixel Luminosity Telescope (PLT), for CMS. We recorded the pixel addresses and pulse heights of all pixels over threshold as well as the fast-or signals from all three telescope planes. We present results on the telescope performance including occupancies, pulse heights, fast-or… Show more

We describe the results from a beam test of a telescope consisting of three planes of single-crystal, diamond pixel detectors. This telescope is a prototype for a proposed small-angle luminosity monitor, the Pixel Luminosity Telescope (PLT), for CMS. We recorded the pixel addresses and pulse heights of all pixels over threshold as well as the fast-or signals from all three telescope planes. We present results on the telescope performance including occupancies, pulse heights, fast-or efficiencies and particle tracking. These results show that the PLT design concept is sound and indicate that the project is ready to proceed with the next phase of carrying out a complete system test, including full optical readout. Show less

The Pixel Luminosity Telescope (PLT) is a dedicated luminosity monitor, presently under construction, for the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC). It measures the particle flux in several three layered pixel diamond detectors that are aligned precisely with respect to each other and the beam direction. At a lower rate it also performs particle track position measurements. The PLTs mono-crystalline CVD diamonds are bump-bonded to the same readout chip used… Show more

The Pixel Luminosity Telescope (PLT) is a dedicated luminosity monitor, presently under construction, for the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC). It measures the particle flux in several three layered pixel diamond detectors that are aligned precisely with respect to each other and the beam direction. At a lower rate it also performs particle track position measurements. The PLTs mono-crystalline CVD diamonds are bump-bonded to the same readout chip used in the silicon pixel system in CMS. Mono-crystalline diamond detectors have many attributes that make them desirable for use in charged particle tracking in radiation hostile environments such as the LHC. In order to further characterize the applicability of diamond technology to charged particle tracking we performed several tests with particle beams that included a measurement of the intrinsic spatial resolution with a high resolution beam telescope. Published by Elsevier B.V. Show less

The Beam Conditions Monitor (BCM) provides fast, relative measurements of particle fluxes for use in the safety systems of CMS. It uses a set of chemical vapor deposited (CVD) diamond diodes. Sudden, order of magnitude changes in the BCM readout issue non-maskable LHC beam aborts. Dangerous irradiation trends on longer timescales translate into automatic detector interlocks and injection inhibit. Operators in the LHC beam and CMS detector control room obtain and display real time (1 Hz) readout… Show more

The Beam Conditions Monitor (BCM) provides fast, relative measurements of particle fluxes for use in the safety systems of CMS. It uses a set of chemical vapor deposited (CVD) diamond diodes. Sudden, order of magnitude changes in the BCM readout issue non-maskable LHC beam aborts. Dangerous irradiation trends on longer timescales translate into automatic detector interlocks and injection inhibit. Operators in the LHC beam and CMS detector control room obtain and display real time (1 Hz) readout of flux measurements from the BCM subsystem. The beam radiation monitoring system also provides an independent measurement of the beam luminosity. The next generation luminosity detector, called the Pixel Luminosity Telescope (PLT), is based on pixelated monocrystalline diamond detectors. They provide a fast occupancy information and allow particle tracking near the interaction point to distinguish trajectories originating from the proton-proton collision point and those parallel to the beam pipe. We present the use case of diamond detectors for beam radiation monitoring in CMS and first measurements of 150 GeV/c ¿+ particle tracks in three layers of pixelated diamond detectors. The PLT after installation in 2010 will be the largest utilization of diamond instrumentation in high energy physics. Show less

We describe the results from a beam test of a telescope consisting of three planes of single-crystal, diamond pixel detectors. This telescope is a prototype for a proposed small-angle luminosity monitor, the Pixel Luminosity Telescope (PLT), for CMS. We recorded the pixel addresses and pulse heights of all pixels over threshold as well as the fast-or signals from all three telescope planes. We present results on the telescope performance including occupancies, pulse heights, fast-or… Show more

We describe the results from a beam test of a telescope consisting of three planes of single-crystal, diamond pixel detectors. This telescope is a prototype for a proposed small-angle luminosity monitor, the Pixel Luminosity Telescope (PLT), for CMS. We recorded the pixel addresses and pulse heights of all pixels over threshold as well as the fast-or signals from all three telescope planes. We present results on the telescope performance including occupancies, pulse heights, fast-or efficiencies and particle tracking. These results show that the PLT design concept is sound and indicate that the project is ready to proceed with the next phase of carrying out a complete system test.
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