61 research outputs found

    Scalar Dark Matter From Theory Space

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    The scalar dark matter candidate in a prototypical theory space little Higgs model is investigated. We review all details of the model pertinent to dark matter. We perform a thermal relic density calculation including couplings to the gauge and Higgs sectors of the model. We find two regions of parameter space that give acceptable dark matter abundances. The first region has a dark matter candidate with a mass of order 100 GeV, the second region has a heavy candidate with a mass greater than about 500 GeV$. The dark matter candidate in either region is an admixture of an SU(2) triplet and an SU(2) singlet, thereby constituting a WIMP (weakly interacting massive particle).Comment: 18 pages, 2 figures, version to appear in PR

    Measurement of the t-channel single top quark production cross section in pp collisions at √s =7 TeV

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    Peer reviewe

    Towards the effective potential of the Littlest Higgs model

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    We compute the relevant parameters of the combined Higgs and \phi scalar effective potential in the Littlest Higgs (LH) model. These parameters are obtained as the sum of two kind of contributions. The first one is the one-loop radiative corrections coming from fermions and gauge bosons. The second one is obtained at the tree level from the higher order effective operators needed for the ultraviolet completion of the model. Finally we analyze the restrictions that the requirement of reproducing the standard electroweak symmetry breaking of the SM set on the LH model parameters.Comment: 23 pages, 3 figures. Version accepted in EPJ

    Transverse-momentum and pseudorapidity distributions of charged hadrons in pp collisions at √s=7 TeV

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    Charged-hadron transverse-momentum and pseudorapidity distributions in proton-proton collisions at root s = 7 TeV are measured with the inner tracking system of the CMS detector at the LHC. The charged-hadron yield is obtained by counting the number of reconstructed hits, hit pairs, and fully reconstructed charged-particle tracks. The combination of the three methods gives a charged-particle multiplicity per unit of pseudorapidity dN(ch)/d eta vertical bar(vertical bar eta vertical bar<0.5) = 5.78 +/- 0.01(stat) +/- 0.23(stat) for non-single-diffractive events, higher than predicted by commonly used models. The relative increase in charged-particle multiplicity from root s = 0.9 to 7 TeV is [66.1 +/- 1.0(stat) +/- 4.2(syst)]%. The mean transverse momentum is measured to be 0.545 +/- 0.005(stat) +/- 0.015(syst) GeV/c. The results are compared with similar measurements at lower energies

    Ratios of dijet production cross sections as a function of the absolute difference in rapidity between jets in proton–proton collisions at sqrts=7mathrmTeVsqrt{s} = 7 mathrm{TeV}

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    A study of dijet production in proton-proton collisions was performed at sqrt(s) = 7 TeV for jets with pt > 35 GeV and abs(y) < 4.7 using data collected with the CMS detector at the LHC in 2010. Events with at least one pair of jets are denoted as 'inclusive'. Events with exactly one pair of jets are called 'exclusive'. The ratio of the cross section of all pairwise combinations of jets to the exclusive dijet cross section as a function of the rapidity difference between jets abs(Delta(y)) is measured for the first time up to abs(Delta(y)) = 9.2. The ratio of the cross section for the pair consisting of the most forward and the most backward jet from the inclusive sample to the exclusive dijet cross section is also presented. The predictions of the Monte Carlo event generators PYTHIA6 and PYTHIA8 agree with the measurements. In both ratios the HERWIG++ generator exhibits a more pronounced rise versus abs(Delta(y)) than observed in the data. The BFKL-motivated generators CASCADE and HEJ+ARIADNE predict for these ratios a significantly stronger rise than observed

    Radiative corrections to the Higgs potential in the LH model

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    In this work we compute the radiative corrections to the Higgs mass and the Higgs quartic couplings coming from the Higgs sector itself and the scalar fields phi in the Littlest Higgs (LH) model. The restrictions that the new contributions set on the parameter space of the models are also discussed. Finally, this work, together with our three previous papers, complete our program addressed to compute the relevant contributions to the Higgs low-energy effective potential in the LH model and the analysis of their phenomenological consequences

    Data and code for demonstrating the Carbon Capture Screening Instrument (CCSI)

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    Data files, source code for instrument operation, computer drawings and machining instructions, and source code for data analysis and figure preparation. All files are in support of the manuscript "Accelerated screening of carbon dioxide capture by liquid sorbents&nbsp;"

    Data and code for demonstrating the Carbon Capture Screening Instrument (CCSI)

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    Data files, source code for instrument operation, computer drawings and machining instructions, and source code for data analysis and figure preparation. All files are in support of the manuscript "Accelerated screening of carbon dioxide capture by liquid sorbents&nbsp;"
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