4,630 research outputs found

    Higgs Boson Discovery Potential of LHC in the Channel pp→γγ+jetpp \to\gamma\gamma+jet

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    We discuss the SM Higgs discovery potential of LHC in the reaction pp→H+jet→γγ+jetpp\to H+ jet\to\gamma\gamma+jet when the jet is observed at sufficiently high EtE_t to be reliably identified. We conclude that this channel gives promising discovery possibilities for the Higgs boson mass range 100-140 GeV, during LHC operation at a low luminosity. With 30 fb−1^{-1} of accumulated data and for MH=120M_H=120 GeV about 100 signal events could be observed with the number of background events larger by a factor of 2 only, showing a signal significance S/B∼7S/\sqrt{B}\sim 7. We use the difference of distributions in the partonic subprocess energy s^\sqrt{\hat s} for the signal and background for a better separation of the signal.Comment: 15 pages including 6 figures, LaTeX, use epsfig.sty. To appear in Phys.Lett.B. In this replacement minor LaTeX improvements are mad

    Monopoles near the Planck Scale and Unification

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    Considering our (3+1)-dimensional space-time as, in some way, discrete or l attice with a parameter a=λPa=\lambda_P, where λP\lambda_P is the Planck length, we have investigated the additional contributions of lattice artifact monopoles to beta-functions of the renormalisation group equations for the running fine structure constants αi(μ)\alpha_i(\mu) (i=1,2,3 correspond to the U(1), SU(2) and SU(3) gauge groups of the Standard Model) in the Family Replicated Gauge Group Model (FRGGM) which is an extension of the Standard Model at high energies. It was shown that monopoles have NfamN_{fam} times smaller magnetic charge in FRGGM than in SM (NfamN_{fam} is the number of families in FRGGM). We have estimated al so the enlargement of a number of fermions in FRGGM leading to the suppression of the asymptotic freedom in the non-Abelian theory. We have shown that, in contrast to the case of AntiGUT when the FRGGM undergoes the breakdown at μ=μG∼1018\mu=\mu_G\sim 10^{18} GeV, we have the possibility of unification if the FRGGM-breakdown occurs at μG∼1014\mu_G\sim 10^{14} GeV. By numerical calculations we obtained an example of the unification of all gauge interactions (including gravity) at the scale μGUT≈1018.4\mu_{GUT}\approx 10^{18.4} GeV. We discussed the possibility of [SU(5)]3[SU(5)]^3 or [SO(10)]3[SO(10)]^3 (SUSY or not SUSY) unifications.Comment: 49 pages, 7 figure

    Scalar meson mediated nuclear mu-e conversion

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    We study the nuclear mu-e conversion in the general framework of the effective Lagrangian approach without referring to any specific realization of the physics beyond the standard model (SM) responsible for lepton flavor violation (LFV). We analyze the role of scalar meson exchange between the lepton and nucleon currents and show its relevance for the coherent channel of mu-e conversion. We show that this mechanism introduces modifications in the predicted mu-e conversion rates in comparison with the conventional direct nucleon mechanism, based on the contact type interactions of the nucleon currents with the LFV leptonic current. We derive from the experimental data lower limits on the mass scales of the generic LFV lepton-quark contact terms and demonstrate that they are more stringent than the similar limits existing in the literature.Comment: 14 pages, 1 figur

    High-resolution remote thermography using luminescent low-dimensional tin-halide perovskites

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    While metal-halide perovskites have recently revolutionized research in optoelectronics through a unique combination of performance and synthetic simplicity, their low-dimensional counterparts can further expand the field with hitherto unknown and practically useful optical functionalities. In this context, we present the strong temperature dependence of the photoluminescence (PL) lifetime of low-dimensional, perovskite-like tin-halides, and apply this property to thermal imaging with a high precision of 0.05 {\deg}C. The PL lifetimes are governed by the heat-assisted de-trapping of self-trapped excitons, and their values can be varied over several orders of magnitude by adjusting the temperature (up to 20 ns {\deg}C-1). Typically, this sensitive range spans up to one hundred centigrade, and it is both compound-specific and shown to be compositionally and structurally tunable from -100 to 110 {\deg} C going from [C(NH2)3]2SnBr4 to Cs4SnBr6 and (C4N2H14I)4SnI6. Finally, through the innovative implementation of cost-effective hardware for fluorescence lifetime imaging (FLI), based on time-of-flight (ToF) technology, these novel thermoluminophores have been used to record thermographic videos with high spatial and thermal resolution.Comment: 25 pages, 4 figure
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