13,879 research outputs found

    Probing New Physics From CP Violation in Radiative B Decays

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    When new CP-violating interactions are dominated by flavor changing neutral particle exchanges, that may occur in many extensions of the standard model. We examine a type 3 two Higgs doublet model and find that direct CP asymmetries can be as large as about 25% . Time-dependent and time-integrated mixing-induced CP asymmetries up to 85 and 40 %, respectively, are possible without conflict with other constraints. It mainly requirs an enhanced chromo-magnetic dipole b→sgb\to sg decay to be close to the present experimental bound.Comment: 7 pages, latex, no figure

    Beyond the Standard Model in B Decays: Three Topics

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    Three new results are discussed: (a) A non-vanishing amplitude for the `wrong sign{'} kaon decay B→J/ΨKˉB \to J/\Psi \bar{K} or its CP conjugate is shown to be a necessary condition for obtaining different CP asymmetries in B→J/ΨKS,LB \to J/\Psi K_{S,L}. A significant effect would require a scale of new physics far below the weak scale, all but ruling out this possibility. (b) The leading isospin breaking contributions to the B→K∗γB \to K^* \gamma decay amplitudes can be calculated in QCD factorization, providing a sensitive probe of the penguin sector of the effective weak Hamiltonian. New physics models which reverse the predicted 10−2010-20% Standard Model amplitude hierarchy could be ruled out with more precise data. (c) A slowly falling g∗gη′g^* g \eta^\prime form factor can be ruled out using the η′\eta^\prime spectrum obtained by ARGUS at the Υ(1S)\Upsilon (1S). The decay b→sgη′b \to s g \eta^\prime is therefore highly suppressed and the origin of the anomalously large B→η′XsB \to \eta^\prime X_s rate remains unknown, perhaps requiring the intervention of New Physics.Comment: 12 pages, 3 figure

    Formation of a condensed state with macroscopic number of phonons in ultracold Bose gases

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    A mechanism for the formation of a new type of stationary state with macroscopical number of phonons in condensed atomic gases is proposed. This mechanism is based on generating longitudinal phonons as a result of parametric resonance caused by a permanent modulation of the transverse trap frequency in an elongated trap. The phonon-phonon interaction predetermines the self-consistent evolution which is completed with macroscopic population of one from all levels within the energy interval of parametric amplification. This level proves to be shifted to the edge of this interval. All other levels end the evolution with zero population.Comment: 9 pages, 8 figure

    The Minimal Modal Interpretation of Quantum Theory

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    We introduce a realist, unextravagant interpretation of quantum theory that builds on the existing physical structure of the theory and allows experiments to have definite outcomes, but leaves the theory's basic dynamical content essentially intact. Much as classical systems have specific states that evolve along definite trajectories through configuration spaces, the traditional formulation of quantum theory asserts that closed quantum systems have specific states that evolve unitarily along definite trajectories through Hilbert spaces, and our interpretation extends this intuitive picture of states and Hilbert-space trajectories to the case of open quantum systems as well. We provide independent justification for the partial-trace operation for density matrices, reformulate wave-function collapse in terms of an underlying interpolating dynamics, derive the Born rule from deeper principles, resolve several open questions regarding ontological stability and dynamics, address a number of familiar no-go theorems, and argue that our interpretation is ultimately compatible with Lorentz invariance. Along the way, we also investigate a number of unexplored features of quantum theory, including an interesting geometrical structure---which we call subsystem space---that we believe merits further study. We include an appendix that briefly reviews the traditional Copenhagen interpretation and the measurement problem of quantum theory, as well as the instrumentalist approach and a collection of foundational theorems not otherwise discussed in the main text.Comment: 73 pages + references, 9 figures; cosmetic changes, added figure, updated references, generalized conditional probabilities with attendant changes to the sections on the EPR-Bohm thought experiment and Lorentz invariance; for a concise summary, see the companion letter at arXiv:1405.675

    Intercluster Correlation in Seismicity

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    Mega et al.(cond-mat/0212529) proposed to use the ``diffusion entropy'' (DE) method to demonstrate that the distribution of time intervals between a large earthquake (the mainshock of a given seismic sequence) and the next one does not obey Poisson statistics. We have performed synthetic tests which show that the DE is unable to detect correlations between clusters, thus negating the claimed possibility of detecting an intercluster correlation. We also show that the LR model, proposed by Mega et al. to reproduce inter-cluster correlation, is insufficient to account for the correlation observed in the data.Comment: Comment on Mega et al., Phys. Rev. Lett. 90. 188501 (2003) (cond-mat/0212529

    Critical Dynamics of a Two-dimensional Superfluid near a Non-Thermal Fixed Point

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    Critical dynamics of an ultracold Bose gas far from equilibrium is studied in two spatial dimensions. Superfluid turbulence is created by quenching the equilibrium state close to zero temperature. Instead of immediately re-thermalizing, the system approaches a meta-stable transient state, characterized as a non-thermal fixed point. A focus is set on the vortex density and vortex-antivortex correlations which characterize the evolution towards the non-thermal fixed point and the departure to final (quasi-)condensation. Two distinct power-law regimes in the vortex-density decay are found and discussed in terms of a vortex binding-unbinding transition and a kinetic description of vortex scattering. A possible relation to decaying turbulence in classical fluids is pointed out. By comparing the results to equilibrium studies of a two-dimensional Bose gas, an intuitive understanding of the location of the non-thermal fixed point in a reduced phase space is developed.Comment: 11 pages, 13 figures; PRA versio
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