295 research outputs found

    The New Sensing Fibre for Application in Optical Fibre Current Sensor

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    The present paper deals with investigations concerning optical fibre current sensors. They are mainly applied in measurements of the intensity of the electric current in the power lines as so-called optical transformers of the electrical current. The most important advantages of fibre current sensors are: safety of service, insulating power as well as their insensitiveness to electromagnetic interference. The investigations were concentrated on designing of adequate sensing fibre, and particularly on the choice of an adequate kind of glass, of which this fibre could be made. Besides, also the head of the fibre current sensor was designed, basing on the suggested and produced sensing fibre. The paper presents the results of magneto-optic tests of the glass and the sensing fibre

    Work fluctuations in quantum spin chains

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    We study the work fluctuations of two types of finite quantum spin chains under the application of a time-dependent magnetic field in the context of the fluctuation relation and Jarzynski equality. The two types of quantum chains correspond to the integrable Ising quantum chain and the nonintegrable XX quantum chain in a longitudinal magnetic field. For several magnetic field protocols, the quantum Crooks and Jarzynski relations are numerically tested and fulfilled. As a more interesting situation, we consider the forcing regime where a periodic magnetic field is applied. In the Ising case we give an exact solution in terms of double-confluent Heun functions. We show that the fluctuations of the work performed by the external periodic drift are maximum at a frequency proportional to the amplitude of the field. In the nonintegrable case, we show that depending on the field frequency a sharp transition is observed between a Poisson-limit work distribution at high frequencies toward a normal work distribution at low frequencies.Comment: 10 pages, 13 figure

    Current large deviations in a driven dissipative model

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    We consider lattice gas diffusive dynamics with creation-annihilation in the bulk and maintained out of equilibrium by two reservoirs at the boundaries. This stochastic particle system can be viewed as a toy model for granular gases where the energy is injected at the boundary and dissipated in the bulk. The large deviation functional for the particle currents flowing through the system is computed and some physical consequences are discussed: the mechanism for local current fluctuations, dynamical phase transitions, the fluctuation-relation

    Test of the photon detection system for the LHCb RICH Upgrade in a charged particle beam

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    The LHCb detector will be upgraded to make more efficient use of the available luminosity at the LHC in Run III and extend its potential for discovery. The Ring Imaging Cherenkov detectors are key components of the LHCb detector for particle identification. In this paper we describe the setup and the results of tests in a charged particle beam, carried out to assess prototypes of the upgraded opto-electronic chain from the Multi-Anode PMT photosensor to the readout and data acquisition system.Comment: 25 pages, 22 figure

    Molecular architecture of the Jumonji C family histone demethylase KDM5B

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    Abstract The full length human histone 3 lysine 4 demethylase KDM5B (PLU-1/Jarid1B) has been studied using Hydrogen/Deuterium exchange mass spectrometry, homology modelling, sequence analysis, small angle X-ray scattering and electron microscopy. This first structure on an intact multi-domain Jumonji histone demethylase reveal that the so-called PLU region, in the central region of KDM5B, has a curved α-helical three-dimensional structure, that acts as a rigid linker between the catalytic core and a region comprising four α-helices, a loop comprising the PHD2 domain, two large intrinsically disordered loops and the PHD3 domain in close proximity. The dumbbell shaped and curved KDM5B architecture observed by electron microscopy is complementary to the nucleosome surface and has a striking overall similarity to that of the functionally related KDM1A/CoREST complex. This could suggest that there are similarities between the demethylation mechanisms employed by the two histone 3 lysine 4 demethylases at the molecular level

    Measurements of π±\pi^\pm, K±^\pm, p and pˉ\bar{\textrm{p}} spectra in proton-proton interactions at 20, 31, 40, 80 and 158 GeV/c with the NA61/SHINE spectrometer at the CERN SPS

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    Measurements of inclusive spectra and mean multiplicities of π±\pi^\pm, K±^\pm, p and pˉ\bar{\textrm{p}} produced in inelastic p+p interactions at incident projectile momenta of 20, 31, 40, 80 and 158 GeV/c (s=\sqrt{s} = 6.3, 7.7, 8.8, 12.3 and 17.3 GeV, respectively) were performed at the CERN Super Proton Synchrotron using the large acceptance NA61/SHINE hadron spectrometer. Spectra are presented as function of rapidity and transverse momentum and are compared to predictions of current models. The measurements serve as the baseline in the NA61/SHINE study of the properties of the onset of deconfinement and search for the critical point of strongly interacting matter

    Observation of associated production of a ZZ boson with a DD meson in the~forward region

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    A search for associated production of a ZZ boson with an open charm meson is presented using a data sample, corresponding to an integrated luminosity of 1.0 fb−‘1.0\,\mathrm{fb}^{-`} of proton--proton collisions at a centre-of-mass energy of 7\,TeV, collected by the LHCb experiment. %% Seven candidate events for associated production of a ZZ boson with a D0D^0 meson and four candidate events for a ZZ boson with a D+D^+ meson are observed with a combined significance of 5.1standard deviations. The production cross-sections in the forward region are measured to be σZ→Ό+ÎŒâˆ’â€‰âŁ,D0=2.50±1.12±0.22pb\sigma_{Z\rightarrow\mu^+\mu^-\!,D^0} = 2.50\pm1.12\pm0.22pb σZ→Ό+ÎŒâˆ’â€‰âŁ,D+=0.44±0.23±0.03pb,\sigma_{Z\rightarrow\mu^+\mu^-\!,D^+} = 0.44\pm0.23\pm0.03pb, where the first uncertainty is statistical and the second systematic.Comment: 18 pages, 2 figure

    Measurements of the B+B^+, B0B^0, Bs0B_s^0 meson and Λb0\Lambda_b^0 baryon lifetimes

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    Measurements of bb-hadron lifetimes are reported using pppp collision data, corresponding to an integrated luminosity of 1.0fb−1^{-1}, collected by the LHCb detector at a centre-of-mass energy of 77Tev. Using the exclusive decays B+→J/ψK+B^+\to J/\psi K^+, B0→J/ψK∗(892)0B^0\to J/\psi K^*(892)^0, B0→J/ψKS0B^0\to J/\psi K^0_{\rm S}, Λb0→J/ψΛ\Lambda_b^0\to J/\psi \Lambda and Bs0→J/ψϕB^0_s\to J/\psi \phi the average decay times in these modes are measured to be τB+→J/ψK+\tau_{B^+\to J/\psi K^+} = 1.637±1.637 \pm 0.004 ±\pm 0.003 ps, τB0→J/ψK∗(892)0\tau_{B^0\to J/\psi K^*(892)^0} = 1.524±1.524 \pm 0.006 ±\pm 0.004 ps, τB0→J/ψKS0\tau_{B^0\to J/\psi K^0_{\rm S}} = 1.499±1.499 \pm 0.013 ±\pm 0.005 ps, τΛb0→J/ψΛ\tau_{\Lambda_b^0\to J/\psi \Lambda} = 1.415±1.415 \pm 0.027 ±\pm 0.006 ps and τBs0→J/ψϕ\tau_{B^0_s\to J/\psi \phi} = 1.480±1.480 \pm 0.011 ±\pm 0.005 ps, where the first uncertainty is statistical and the second is systematic. These represent the most precise lifetime measurements in these decay modes. In addition, ratios of these lifetimes, and the ratio of the decay-width difference, ΔΓd\Delta\Gamma_d, to the average width, Γd\Gamma_d, in the B0B^0 system, ΔΓd/Γd=−0.044±0.025±0.011\Delta \Gamma_d/\Gamma_d = -0.044 \pm 0.025 \pm 0.011, are reported. All quantities are found to be consistent with Standard Model expectations.Comment: 28 pages, 4 figures. Updated reference
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