11,552 research outputs found

    Study on space-time structure of Higgs boson decay using HBT correlation Method in e+^+e^- collision at s\sqrt{s}=250 GeV

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    The space-time structure of the Higgs boson decay are carefully studied with the HBT correlation method using e+^+e^- collision events produced through Monte Carlo generator PYTHIA 8.2 at s\sqrt{s}=250GeV. The Higgs boson jets (Higgs-jets) are identified by H-tag tracing. The measurement of the Higgs boson radius and decay lifetime are derived from HBT correlation of its decay final state pions inside Higgs-jets in the e+^+e^- collisions events with an upper bound of RH1.03±0.05R_H \le 1.03\pm 0.05 fm and τH(1.29±0.15)×107\tau_H \le (1.29\pm0.15)\times 10^{-7} fs. This result is consistent with CMS data.Comment: 7 pages,3 figure

    Hamilton-Jacobi Method and Gravitation

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    Studying the behaviour of a quantum field in a classical, curved, spacetime is an extraordinary task which nobody is able to take on at present time. Independently by the fact that such problem is not likely to be solved soon, still we possess the instruments to perform exact predictions in special, highly symmetric, conditions. Aim of the present contribution is to show how it is possible to extract quantitative information about a variety of physical phenomena in very general situations by virtue of the so-called Hamilton-Jacobi method. In particular, we shall prove the agreement of such semi-classical method with exact results of quantum field theoretic calculations.Comment: To appear in the proceedings of "Cosmology, the Quantum Vacuum, and Zeta Functions": A workshop with a celebration of Emilio Elizalde's Sixtieth birthday, Bellaterra, Barcelona, Spain, 8-10 Mar 201

    Effect of Composition on the Photoelectrochemical Behavior of Anodic Oxides on Binary Aluminum Alloys

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    The photoelectrochemical behavior of anodic films on Al alloys, containing titanium, tantalum, and tungsten (valve metals), has been studied as a function of alloy composition and anodizing conditions. Photocurrent spectroscopy has been used to get information on bandgap and the flatband potential values of different mixed oxides. Both insulator-like and semiconducting behavior has been observed for anodic oxides grown on Al-W and Al-Ti alloys dependent on alloy initial composition. Optical bandgap values, Eg,opt, of different oxides are in accordance with predictions based on the correlation between Eg,opt and the difference of electronegativities of the oxide constituents, indicating potential for tailoring solid state properties of ternary oxides

    1 Hop or 2 hops: Topology analysis in Body Area Network

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    Wireless Body Area Networks (WBANs) have recently received much attention due to the possibility to be used in healthcare applications. For these applications, link reliability and energy efficiency are critical issues, as in many cases, information carried can be vital for the patient and batteries cannot be easily replaced. The wireless on-body channel experiences significant temporal variation due to body movements and the use of relays is sometimes necessary in order to guarantee reliability or improve lifetime. In this paper, an experimental evaluation is used to give a better understanding about reliability, energy consumption and lifetime in a single hop or a two hops communication. This analysis keeps into consideration the correlations between propagation on different links which affect simultaneously the time-varying connectivity on different links of the body. Theresults shows that an off-body relays could be used to increase data reliability, minimize energy requirements and maximize network lifetime

    The Zeroth Law of Thermodynamics and Volume-Preserving Conservative Dynamics with Equilibrium Stochastic Damping

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    We propose a mathematical formulation of the zeroth law of thermodynamics and develop a stochastic dynamical theory, with a consistent irreversible thermodynamics, for systems possessing sustained conservative stationary current in phase space while in equilibrium with a heat bath. The theory generalizes underdamped mechanical equilibrium: dx=gdt+{Dϕdt+2DdB(t)}dx=gdt+\{-D\nabla\phi dt+\sqrt{2D}dB(t)\}, with g=0\nabla\cdot g=0 and {}\{\cdots\} respectively representing phase-volume preserving dynamics and stochastic damping. The zeroth law implies stationary distribution uss(x)=eϕ(x)u^{ss}(x)=e^{-\phi(x)}. We find an orthogonality ϕg=0\nabla\phi\cdot g=0 as a hallmark of the system. Stochastic thermodynamics based on time reversal (t,ϕ,g)(t,ϕ,g)\big(t,\phi,g\big)\rightarrow\big(-t,\phi,-g\big) is formulated: entropy production ep#(t)=dF(t)/dte_p^{\#}(t)=-dF(t)/dt; generalized "heat" hd#(t)=dU(t)/dth_d^{\#}(t)=-dU(t)/dt, U(t)=Rnϕ(x)u(x,t)dxU(t)=\int_{\mathbb{R}^n} \phi(x)u(x,t)dx being "internal energy", and "free energy" F(t)=U(t)+Rnu(x,t)lnu(x,t)dxF(t)=U(t)+\int_{\mathbb{R}^n} u(x,t)\ln u(x,t)dx never increases. Entropy follows dSdt=ep#hd#\frac{dS}{dt}=e_p^{\#}-h_d^{\#}. Our formulation is shown to be consistent with an earlier theory of P. Ao. Its contradistinctions to other theories, potential-flux decomposition, stochastic Hamiltonian system with even and odd variables, Klein-Kramers equation, Freidlin-Wentzell's theory, and GENERIC, are discussed.Comment: 25 page

    Horizontal rotation signals detected by "G-Pisa" ring laser for the Mw=9.0, March 2011, Japan earthquake

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    We report the observation of the ground rotation induced by the Mw=9.0, 11th of March 2011, Japan earthquake. The rotation measurements have been conducted with a ring laser gyroscope operating in a vertical plane, thus detecting rotations around the horizontal axis. Comparison of ground rotations with vertical accelerations from a co-located force-balance accelerometer shows excellent ring laser coupling at periods longer than 100s. Under the plane wave assumption, we derive a theoretical relationship between horizontal rotation and vertical acceleration for Rayleigh waves. Due to the oblique mounting of the gyroscope with respect to the wave direction-of-arrival, apparent velocities derived from the acceleration / rotation rate ratio are expected to be always larger than, or equal to the true wave propagation velocity. This hypothesis is confirmed through comparison with fundamental-mode, Rayleigh wave phase velocities predicted for a standard Earth model.Comment: Accepted for publication in Journal of Seismolog

    Superconducting tantalum disulfide nanotapes; growth, structure and stoichiometry

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    Superconducting tantalum disulfide nanowires have been synthesised by surface-assisted chemical vapour transport (SACVT) methods and their crystal structure, morphology and stoichiometry studied by powder X-ray diffraction (PXD), scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and nanodiffraction. The evolution of morphology, stoichiometry and structure of materials grown by SACVT methods in the Ta-S system with reaction temperature was investigated systematically. High-aspect-ratio, superconducting disulfide nanowires are produced at intermediate reaction temperatures (650 degrees C). The superconducting wires are single crystalline, adopt the 2H polytypic structure (hexagonal space group P6(3)/mmc: a = 3.32(2) angstrom, c = 12.159(2) angstrom; c/a = 3.66) and grow in the <2<(1)over bar>(1) over bar0> direction. The nanowires are of rectangular cross-section forming nanotapes composed of bundles of much smaller fibres that grow cooperatively. At lower reaction temperatures nanowires close to a composition of TaS3 are produced whereas elevated temperatures yield platelets of 1T TaS2

    Comparing Signal Setting Design Methods through emissions and fuel consumption performance indicators

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    In order to address the Signal Setting Design at urban level two main approaches may be pursued: the coordination and the synchronisation approaches depending on the steps considered for the optimisation of decision variables (two steps vs. one step). Furthermore, in terms of objective functions mono-criterion or multi-criteria may be adopted. In this paper the coordination approach is implemented considering the multi-criteria optimisation at single junctions and mono-criterion optimisation at network level whereas the synchronisation is implemented considering the mono-criterion optimisation. The main purpose of the paper is the evaluation of the performances of two strategies not only considering indicators such as the total delay, the queue length etc. but also considering other indicators such as the emissions and the fuel consumption. The methodological framework is composed by three stages: (i) the decision variables (green timings and offsets) computation through optimisation methods; (ii) the implementation of optimal signal settings in a microscopic traffic flow simulator (“Simulation of Urban MObility”-SUMO); (iii) the estimation of emissions and fuel consumption indicators
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