4,928 research outputs found

    The CMS Modular Track Finder boards, MTF6 and MTF7

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    To accommodate the increase in energy and luminosity of the upgraded LHC, the CMS Endcap Muon Level 1 Trigger system has to be significantly modified. To provide the best track reconstruction, the Trigger system must now import all available trigger primitives generated by Cathode Strip Chambers and by other regional subsystems, such as Resistive Plate Chambers. In addition to massive input bandwidth, this also requires a significant increase in logic and memory resources. To satisfy these requirements, a new Sector Processor unit for muon track finding is being designed. This unit follows the micro-TCA standard recently adopted by CMS. It consists of three modules. The Core Logic module houses the large FPGA that contains the processing logic and multi-gigabit serial links for data exchange. The Optical module contains optical receivers and transmitters; it communicates with the Core Logic module via a custom backplane section. The Look-Up Table module contains a large amount of low-latency memory that is used to assign the final transverse momentum of the muon candidate tracks. The name of the unit — Modular Track Finder — reflects the modular approach used in the design. Presented here are the details of the hardware design of the prototype unit based on Xilinx's Virtex-6 FPGA family, MTF6, as well as results of the conducted tests. Also presented are plans for the pre-production prototype based on the Virtex-7 FPGA family, MTF7

    Search for Doubly-Charged Higgs Boson Production at HERA

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    A search for the single production of doubly-charged Higgs bosons H^{\pm \pm} in ep collisions is presented. The signal is searched for via the Higgs decays into a high mass pair of same charge leptons, one of them being an electron. The analysis uses up to 118 pb^{-1} of ep data collected by the H1 experiment at HERA. No evidence for doubly-charged Higgs production is observed and mass dependent upper limits are derived on the Yukawa couplings h_{el} of the Higgs boson to an electron-lepton pair. Assuming that the doubly-charged Higgs only decays into an electron and a muon via a coupling of electromagnetic strength h_{e \mu} = \sqrt{4 \pi \alpha_{em}} = 0.3, a lower limit of 141 GeV on the H^{\pm\pm} mass is obtained at the 95% confidence level. For a doubly-charged Higgs decaying only into an electron and a tau and a coupling h_{e\tau} = 0.3, masses below 112 GeV are ruled out.Comment: 15 pages, 3 figures, 1 tabl

    Forward pi^0 Production and Associated Transverse Energy Flow in Deep-Inelastic Scattering at HERA

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    Deep-inelastic positron-proton interactions at low values of Bjorken-x down to x \approx 4.10^-5 which give rise to high transverse momentum pi^0 mesons are studied with the H1 experiment at HERA. The inclusive cross section for pi^0 mesons produced at small angles with respect to the proton remnant (the forward region) is presented as a function of the transverse momentum and energy of the pi^0 and of the four-momentum transfer Q^2 and Bjorken-x. Measurements are also presented of the transverse energy flow in events containing a forward pi^0 meson. Hadronic final state calculations based on QCD models implementing different parton evolution schemes are confronted with the data.Comment: 27 pages, 8 figures and 3 table

    Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV

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    A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7 TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440 GeV range is excluded at 95% confidence level.Comment: Submitted to JHE
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