1,557 research outputs found

    CP Violation in \tau ->\nu\pi K_S and D->\pi K_S: The Importance of K_S-K_L Interference

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    The BB-factories have measured CP asymmetries in the τπKSν\tau\to\pi K_S\nu and DKSπD\to K_S\pi modes. The KSK_S state is identified by its decay to two pions at a time that is close to the KSK_S lifetime. Within the Standard Model and many of its extensions, the asymmetries in these modes come from CP violation in K0Kˉ0K^0-\bar{K}^0 mixing. We emphasize that the interference between the amplitudes of intermediate KSK_S and KLK_L is as important as the pure KSK_S amplitude. Consequently, the measured asymmetries depend on the times over which the relevant decay rates are integrated and on features of the experiment.Comment: 4 pages, 4 figure

    Noise Effects on the Complex Patterns of Abnormal Heartbeats

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    Patients at high risk for sudden death often exhibit complex heart rhythms in which abnormal heartbeats are interspersed with normal heartbeats. We analyze such a complex rhythm in a single patient over a 12-hour period and show that the rhythm can be described by a theoretical model consisting of two interacting oscillators with stochastic elements. By varying the magnitude of the noise, we show that for an intermediate level of noise, the model gives best agreement with key statistical features of the dynamics.Comment: 4 pages, 4 figures, RevTe

    Magnitude and Sign Correlations in Heartbeat Fluctuations

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    We propose an approach for analyzing signals with long-range correlations by decomposing the signal increment series into magnitude and sign series and analyzing their scaling properties. We show that signals with identical long-range correlations can exhibit different time organization for the magnitude and sign. We find that the magnitude series relates to the nonlinear properties of the original time series, while the sign series relates to the linear properties. We apply our approach to the heartbeat interval series and find that the magnitude series is long-range correlated, while the sign series is anticorrelated and that both magnitude and sign series may have clinical applications.Comment: 4 pages,late

    Final State Interactions and New Physics in B -> pi K Decays

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    Within the Standard Model, and if one assumes that soft rescattering effects are negligible, the CP asymmetry A^dir_CP (B^\pm -> \pi^\pm K) is predicted to be very small and the ratio R = BR(B_d -> \pi^\mp K^\pm)/BR(B^\pm -> \pi^\pm K) provides a bound on the angle \gamma of the unitarity triangle, sin^2 \gamma \leq R. We estimate the corrections from soft rescattering effects using an approach based on Regge phenomenology, and find effects of order 10% with large uncertainties. In particular, we conclude that A^dir_CP \sim 0.2 and sin^2 \gamma \sim 1.2 R could not be taken unambiguously to signal New Physics. Using SU(3) relations, we suggest experimental tests that could constrain the size of the soft rescattering effects thus reducing the related uncertainty. Finally, we study the effect of various models of New Physics on A^dir_CP and on R.Comment: 20 pages, RevTex, no figures; a few typos corrected, references added, brief additional discussion of uncertanties is adde

    Testing the Standard Model and Schemes for Quark Mass Matrices with CP Asymmetries in B Decays

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    The values of sin(2α)\sin (2 \alpha) and sin(2β)\sin (2 \beta), where α\alpha and β\beta are angles of the unitarity triangle, will be readily measured in a B factory (and maybe also in hadron colliders). We study the standard model constraints in the sin(2α)sin(2β)\sin (2 \alpha) - \sin (2 \beta) plane. We use the results from recent analyses of fBf_B and τbVcb2\tau_b|V_{cb}|^2 which take into account heavy quark symmetry considerations. We find sin(2β)0.15\sin (2 \beta) \geq 0.15 and most likely \sin (2 \beta) \roughly{>} 0.6, and emphasize the strong correlations between sin(2α)\sin (2 \alpha) and sin(2β)\sin (2 \beta). Various schemes for quark mass matrices allow much smaller areas in the sin(2α)sin(2β)\sin (2 \alpha) - \sin (2 \beta) plane. We study the schemes of Fritzsch, of Dimopoulos, Hall and Raby, and of Giudice, as well as the ``symmetric CKM'' idea, and show how CP asymmetries in B decays will crucially test each of these schemes.Comment: 11 pages and 4 postscript figures available on request, LaTeX, WIS-92/52/Jun-PH, LBL-3256

    Modeling resilience and sustainability in ancient agricultural systems

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    The reasons why people adopt unsustainable agricultural practices, and the ultimate environmental implications of those practices, remain incompletely understood in the present world. Archaeology, however, offers unique datasets on coincident cultural and ecological change, and their social and environmental effects. This article applies concepts derived from ecological resilience thinking to assess the sustainability of agricultural practices as a result of long-term interactions between political, economic, and environmental systems. Using the urban center of Gordion, in central Turkey, as a case study, it is possible to identify mismatched social and ecological processes on temporal, spatial, and organizational scales, which help to resolve thresholds of resilience. Results of this analysis implicate temporal and spatial mismatches as a cause for local environmental degradation, and increasing extralocal economic pressures as an ultimate cause for the adoption of unsustainable land-use practices. This analysis suggests that a research approach that integrates environmental archaeology with a resilience perspective has considerable potential for explicating regional patterns of agricultural change and environmental degradation in the past

    Comparisons of binary black hole merger waveforms

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    This a particularly exciting time for gravitational wave physics. Ground-based gravitational wave detectors are now operating at a sensitivity such that gravitational radiation may soon be directly detected, and recently several groups have independently made significant breakthroughs that have finally enabled numerical relativists to solve the Einstein field equations for coalescing black-hole binaries, a key source of gravitational radiation. The numerical relativity community is now in the position to begin providing simulated merger waveforms for use by the data analysis community, and it is therefore very important that we provide ways to validate the results produced by various numerical approaches. Here, we present a simple comparison of the waveforms produced by two very different, but equally successful approaches--the generalized harmonic gauge and the moving puncture methods. We compare waveforms of equal-mass black hole mergers with minimal or vanishing spins. The results show exceptional agreement for the final burst of radiation, with some differences attributable to small spins on the black holes in one case.Comment: Revtex 4, 5 pages. Published versio
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