3,396 research outputs found

    Local and Effective Temperatures of Quantum Driven Systems

    Get PDF
    We introduce thermometers to define the local temperature of an electronic system driven out-of-equilibrium by local AC fields. We also define the effective temperature in terms of a local fluctuation-dissipation-relation. We show that within the weak driving regime these two temperatures coincide. We also discuss the behavior of the local temperature along the sample. We show that it exhibits spatial fluctuations following an oscillatory pattern. For weak driving, regions of the sample become heated, while others become cooled as a consequence of the driving

    Multi-rate demodulator architecture

    Get PDF
    A unique digital multi-rate demodulator (MRD) architecture is presented for onboard satellite communications processing. The multi-rate feature enables the same demodulator hardware to process either one wideband channel (WBC), or process up to thirty-two independent narrowband channels (NBC) that are time division multiplexed (TDM). The MRD can process many quadrature modulation format such as offset quadrature phase shift keying (OQPSK). Possible applications include voice and data transmission for commercial or military users

    Relation Between Local Temperature Gradients and the Direction of Heat Flow in Quantum Driven Systems

    Full text link
    We introduce thermometers to define the local temperature of an electronic system driven out-of-equilibrium by local ac fields. We discuss the behavior of the local temperature along the sample, showing that it exhibits spatial fluctuations following an oscillatory pattern. We show explicitly that the local temperature is the correct indicator for heat flow.Comment: 3 pages, 2 figure

    Observation of a Broad L=1 cqˉc\bar{q} State in BD+ππB^{-}\to D^{*+}\pi^{-}\pi^{-} at CLEO

    Full text link
    Using 4.7 fb^-1 of data taken at CESR at energies at and near the Upsilon(4S) we have studied the decay B- -> D{*+}pi-pi- (and its conjugate). We observe a new, broad charmed meson state, which we interpret as D_J(j=1/2), in its decay to D{*+}pi-. Our preliminary results indicate the mass and width of this L=1 state to be m = (2461 +41/-3} +/-10 +/-32) MeV and Gamma = (290 +101/-79 +/-26 +/-36) MeV, with the third uncertainty associated with the parameterization of the relative strong phases. In addition we have measured several new branching fractions of charged B mesons. All quoted results are preliminary.Comment: 7 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

    Long distance contribution to BKKπ+B^- \to K^- K^- \pi^+, - a searching ground mode for new physics

    Full text link
    The decay BKKπ+B^- \to K^- K^- \pi^+ has been sugested as a test for minimal supersymmetric standard model and for supersymmetric models with R-parity violating couplings, in view of its extreme smallnesss in the standard model. We calculate two long distance contributions to this decay, that associated with DDDD and DπD\pi intermediate states and that induced by virtual DD, π\pi mesons. The branching ratio due to these contributions is 6×10126 \times 10^{-12}, which is somewhat smaller than the standard model short distance result, leaving this decay free for the search of new physics.Comment: 13 pages, 2 figures, revised versio

    Predictions for the unitarity triangle angles in a new parametrization

    Get PDF
    A new approach to the parametrization of the CKM matrix, VV, is considered in which VV is written as a linear combination of the unit matrix II and a non-diagonal matrix UU which causes intergenerational-mixing, that is V=cosθI+isinθUV=\cos\theta I+i\sin\theta U. Such a VV depends on 3 real parameters including the parameter θ\theta. It is interesting that a value of θ=π/4\theta=\pi/4 is required to fit the available data on the CKM-matrix including CP-violation. Predictions of this fit for the angles α\alpha, β\beta and γ\gamma for the unitarity triangle corresponding to V11V13+V21V23+V31V33=0V_{11}V^*_{13} + V_{21} V^*_{23} +V_{31}V^*_{33} =0, are given. For θ\theta=π/4\pi/4, we obtain α=88.46\alpha=88.46^\circ, β=45.046\beta=45.046^\circ and γ=46.5\gamma=46.5^\circ. These values are just about in agreement, within errors, with the present data. It is very interesting that the unitarity triangle is expected to be approximately a right-angled, isosceles triangle. Our prediction sin2β=1\sin 2\beta = 1 is in excellent agreement with the value 0.99±0.15±0.050.99\pm 0.15\pm 0.05 reported by the Belle collaboration at the Lepton-Photon 2001 meeting.Comment: 11 pages, latex, no figure

    CP, T and CPT Violations in the K^0 - bar{K^0} System -- Present Status --

    Full text link
    Possible violation of CP, T and CPT symmetries in the K^0 - bar{K^0} system is studied in a way as phenomenological and comprehensive as possible. For this purpose, we first introduce parameters which represent violation of these symmetries in mixing parameters and decay amplitudes in a convenient and well-defined way and, treating these parameters as small, derive formulas which relate them to the experimentally measured quantities. We then perform numerical analyses to derive constraints to these symmetry-violating parameters, with the latest data reported by KTeV Collaboration, NA48 Collaboration and CPLEAR Collaboration, along with those compiled by Particle Data Group, used as inputs. The result obtained by CPLEAR Collaboration from an unconstrained fit to a time-dependent leptonic asymmetry, aided by the Bell-Steinberger relation, enables us to determine or constrain most of the parameters separately. It is shown among the other things that (1) CP and T symmetries are violated definitively at least at the level of 10^{-4} in 2 pi decays, (2) CP and T symmetries are violated at least at the level of 10^{-3} in the K^0 - bar{K^0} mixing, and (3) CPT symmetry is at present tested to the level of 10^{-5} at the utmost.Comment: 20 page

    Review of Recent Searches for Rare and Forbidden Dilepton Decays of Charmed Mesons

    Get PDF
    I briefly review the results of recent searches for flavor-changing neutral current and lepton-flavor and lepton-number violating decays of D+, Ds, and D0 mesons (and their antiparticles) into modes containing muons and electrons. The primary focus is the results from Fermilab charm hadroproduction experiment E791. E791 examined 24 pi,l,l and K,l,l decay modes of D+ and Ds and l+l- decay modes of D0. Limits presented by E791 for 22 rare and forbidden dilepton decays of D mesons were more stringent than those obtained from previous searches, or else were the first reported.Comment: 8 pages, 1 figure, uses psfig.sty and RevTeX, submitted to Modern Physics Letters A, based on a Fermilab "Joint Theoretical and Experimental" tal

    Primordial Nucleosynthesis: Accurate Predictions

    Get PDF
    A new accurate evaluation of primordial light nuclei abundances is presented. The proton to neutron conversion rates have been corrected to take into account radiative effects, finite nucleon mass, thermal and plasma corrections. The theoretical uncertainty on 4He is so reduced to the order of 0.1%.Comment: 4 pages, Talk given at the International Workshop on Particles in Astrophysics and Cosmology: From Theory to Observation, Valencia 199

    Perturbative QCD Correction to the Light-Cone Sum Rule for the BBπB^*B\pi and DDπD^*D\pi Couplings

    Full text link
    The BBπB^*B\pi and DDπD^*D\pi couplings have previously been derived from a QCD light-cone sum rule in leading order. Here, we describe the calculation of the O(αs)O(\alpha_s) correction to the twist 2 term of this sum rule. The result is used for a first next-to-leading order analysis. We obtain gBBπ=22±7g_{B^*B\pi}= 22\pm 7 and gDDπ=10.5±3g_{D^*D\pi}=10.5\pm 3, where the error indicates the remaining theoretical uncertainty.Comment: 11 pages, 1 figure, Latex, epsfi
    corecore