Prospects of Detecting Massive Charged Higgs from Hadronic Decay H -> tb in CMS

The possibility to detect the massive charged Higgs boson H using the hadronic decay channel H -> tb in the associated production pp -> tH + X in the CMS experiment at LHC is studied. There is a large background from ttbb events which makes the observation difficult. Detection of a Higgs signal in this channel requires an excellent b-tagging performance. Good calorimeter mass resolution is also necessary for the full event reconstruction.Comment: 13 pages, 18 figure

Discovery potential for Higgs bosons beyond the SM

The discovery potential of the CMS detector for the MSSM neutral and charged Higgs bosons at the LHC is presented based on studies with full detector simulation and event reconstruction of the principal discovery channels.Comment: Prepared for International Europhysics Conference on High Energy Physics (EPS-HEP2007), Manchester, England, 19-25 Jul 200

Next-to-leading order QCD corrections to W+W- production via vector-boson fusion

Vector-boson fusion processes constitute an important class of reactions at hadron colliders, both for signals and backgrounds of new physics in the electroweak interactions. We consider what is commonly referred to as W+W- production via vector-boson fusion (with subsequent leptonic decay of the Ws), or, more precisely, e+ nu_e mu- nubar_mu + 2 jets production in proton-proton scattering, with all resonant and non-resonant Feynman diagrams and spin correlations of the final-state leptons included, in the phase-space regions which are dominated by t-channel electroweak-boson exchange. We compute the next-to-leading order QCD corrections to this process, at order alpha^6 alpha_s. The QCD corrections are modest, changing total cross sections by less than 10%. Remaining scale uncertainties are below 2%. A fully-flexible next-to-leading order partonic Monte Carlo program allows to demonstrate these features for cross sections within typical vector-boson-fusion acceptance cuts. Modest corrections are also found for distributions.Comment: 29 pages, 14 figure

Dominant next-to-leading order QCD corrections to Higgs plus three jet production in vector-boson fusion

We present the calculation of the dominant next to leading order QCD corrections to Higgs boson production in association with three jets via vector boson fusion in the form of a NLO parton-level Monte Carlo program. QCD corrections to integrated cross sections are modest, while the shapes of some kinematical distributions change appreciably at NLO. Scale uncertainties are shown to be reduced at NLO for the total cross section and for distributions. We consider a central jet veto at the LHC and analyze the veto probability for typical vector boson fusion cuts. Scale uncertainties of the veto probability are sufficiently small at NLO for precise Higgs coupling measurements at the LHC.Comment: 40 pages, 17 figures, 2 tables, published versio

Effect of a thin AlO_x layer on transition-edge sensor properties

We have studied the physics of transition-edge sensor (TES) devices with an insulating AlOx layer on top of the device to allow implementation of more complex detector geometries. By comparing devices with and without the insulating film, we have observed significant additional noise apparently caused by the insulator layer. In addition, AlOx was found to be a relatively good thermal conductor. This adds an unforeseen internal thermal feature to the system.Comment: 6 pages, 5 figures, Low Temperature Detectors 14 conferenc

A transmission problem across a fractal self-similar interface

We consider a transmission problem in which the interior domain has infinitely ramified structures. Transmission between the interior and exterior domains occurs only at the fractal component of the interface between the interior and exterior domains. We also consider the sequence of the transmission problems in which the interior domain is obtained by stopping the self-similar construction after a finite number of steps; the transmission condition is then posed on a prefractal approximation of the fractal interface. We prove the convergence in the sense of Mosco of the energy forms associated with these problems to the energy form of the limit problem. In particular, this implies the convergence of the solutions of the approximated problems to the solution of the problem with fractal interface. The proof relies in particular on an extension property. Emphasis is put on the geometry of the ramified domain. The convergence result is obtained when the fractal interface has no self-contact, and in a particular geometry with self-contacts, for which an extension result is proved

Summary of the CMS Discovery Potential for the MSSM SUSY Higgses

This work summarises the present understanding of the expected MSSM SUSY Higgs reach for CMS. Many of the studies presented here result from detailed detector simulations incorporating final CMS detector design and response. With 30 fb-1 the h -> gamma,gamma and h -> bb channels allow to cover most of the MSSM parameter space. For the massive A,H,H+ MSSM Higgs states the channels A,H -> tau,tau and H+ -> tau,nu turn out to be the most profitable ones in terms of mass reach and parameter space coverage. Consequently CMS has made a big effort to trigger efficiently on taus. Provided neutralinos and sleptons are not too heavy, there is an interesting complementarity in the reaches for A,H -> tau,tau and A,H -> chi,chi.Comment: 19 pages, 27 figure

Readout of solid-state charge qubits using a single-electron pump

A major difficulty in realizing a solid-state quantum computer is the reliable measurement of the states of the quantum registers. In this paper, we propose an efficient readout scheme making use of the resonant tunneling of a ballistic electron produced by a single electron pump. We treat the measurement interaction in detail by modeling the full spatial configuration, and show that for pumped electrons with suitably chosen energy the transmission coefficient is very sensitive to the qubit state. We further show that by using a short sequence of pumping events, coupled with a simple feedback control procedure, the qubit can be measured with high accuracy.Comment: 5 pages, revtex4, 4 eps figures. v2: published versio