The decays K→ππνν‾K \to \pi \pi \nu \overline\nu within the standard model

We study the reactions $K \rightarrow \pi \pi \nu \overline{\nu}$ within the minimal standard model. We use isospin symmetry to relate the matrix elements to the form factors measured in $K_{\ell 4}$. We argue that these modes are short distance dominated and can be used for precise determinations of the CKM parameters $\rho$ and $\eta$. Depending on the value of the CKM angles we find branching ratios in the following ranges: $B(K_L \rightarrow \pi^+ \pi^- \nu \overline{\nu}) = [2-5] \times 10^{-13}$; $B(K_L \rightarrow \pi^0 \pi^0 \nu \overline{\nu}) = [1-3] \times 10^{-13}$; $B(K^+ \rightarrow \pi^+ \pi^0 \nu \overline{\nu}) = [1-2] \times 10^{-14}$. We also discuss a possible $CP$-odd observable.Comment: 10 pages, LaTeX, 2 Postscript figures. Title and abstract have been revised to better reflect the content of the paper. This is the final version as publishe

Prospects for observing ultra-compact binaries with space-based gravitational wave interferometers and optical telescopes

Space-based gravitational wave interferometers are sensitive to the galactic population of ultra-compact binaries. An important subset of the ultra-compact binary population are those stars that can be individually resolved by both gravitational wave interferometers and electromagnetic telescopes. The aim of this paper is to quantify the multi-messenger potential of space-based interferometers with arm-lengths between 1 and 5 Gm. The Fisher Information Matrix is used to estimate the number of binaries from a model of the Milky Way which are localized on the sky by the gravitational wave detector to within 1 and 10 square degrees and bright enough to be detected by a magnitude limited survey. We find, depending on the choice of GW detector characteristics, limiting magnitude, and observing strategy, that up to several hundred gravitational wave sources could be detected in electromagnetic follow-up observations.Comment: 6 pages, 3 figures Updated to include new results. Submitted to MNRA

Rare Kaon Decays

The current status of rare kaon decay experiments is reviewed. New limits in the search for Lepton Flavor Violation are discussed, as are new measurements of the CKM matrix.Comment: 8 pages, 3 figures, LaTeX, presented at the 3rd International Conference on B Phyiscs and CP Violation, Taipei December 3-7, 199

Limitations of diabetes pharmacotherapy: results from the Vermont Diabetes Information System study

BACKGROUND: There are a wide variety of medications available for the treatment of hyperglycemia in diabetes, including some categories developed in recent years. The goals of this study were to describe the glycemic medication profiles in a cohort of adult patients enrolled in primary care, to compare the regimens with measures of glycemic control, and to describe potential contraindicated regimens. METHODS: One thousand and six subjects with diabetes cared for in community practices in the Northeast were interviewed at home at the time of enrollment in a trial of a diabetes decision support system. Laboratory data were obtained directly from the clinical laboratory. Current medications were obtained by direct observation of medication containers by a research assistant. RESULTS: The median age of subjects was 63 years; 54% were female. The mean A1C was 7.1%, with 60% of subjects in excellent glycemic control (A1C < 7%). Ninety percent of patients were taking 2 or fewer medications for glycemic control, with a range of 0 to 4 medications. Insulin was used by 18%. As the number of diabetes medications increased from 0 to 4, the A1C increased from 6.5% to 9.2% (p < 0.001). The association between glycemic control and number of glycemic medications was confirmed using logistic regression, controlling for potential confounders. Almost 20% of subjects on metformin or thiazolidenediones had potential contraindications to these medications. CONCLUSION: Patients with diabetes cared for in primary care are on a wide variety of medication combinations for glycemic control, though most are on two or fewer medications. A greater number of diabetes medications is associated with poorer glycemic control, reflecting the limitations of current pharmacotherapy. One quarter of patients are on glycemic medications with potential contraindications

Tests of Bayesian Model Selection Techniques for Gravitational Wave Astronomy

The analysis of gravitational wave data involves many model selection problems. The most important example is the detection problem of selecting between the data being consistent with instrument noise alone, or instrument noise and a gravitational wave signal. The analysis of data from ground based gravitational wave detectors is mostly conducted using classical statistics, and methods such as the Neyman-Pearson criteria are used for model selection. Future space based detectors, such as the \emph{Laser Interferometer Space Antenna} (LISA), are expected to produced rich data streams containing the signals from many millions of sources. Determining the number of sources that are resolvable, and the most appropriate description of each source poses a challenging model selection problem that may best be addressed in a Bayesian framework. An important class of LISA sources are the millions of low-mass binary systems within our own galaxy, tens of thousands of which will be detectable. Not only are the number of sources unknown, but so are the number of parameters required to model the waveforms. For example, a significant subset of the resolvable galactic binaries will exhibit orbital frequency evolution, while a smaller number will have measurable eccentricity. In the Bayesian approach to model selection one needs to compute the Bayes factor between competing models. Here we explore various methods for computing Bayes factors in the context of determining which galactic binaries have measurable frequency evolution. The methods explored include a Reverse Jump Markov Chain Monte Carlo (RJMCMC) algorithm, Savage-Dickie density ratios, the Schwarz-Bayes Information Criterion (BIC), and the Laplace approximation to the model evidence. We find good agreement between all of the approaches.Comment: 11 pages, 6 figure

Physics with low energy hadrons

The prospects for low energy hadron physics at the front end of a muon collider (FMC) are discussed. The FMC, as conceived for the purposes of this workshop, is pretty close to a classical idea of a koan factory. There is an order of magnitude advantage of the FMC front end over the AGS for K{sup {minus}} and {anti p} production below 5 GeV/c

Flavor-Changing Processes in Extended Technicolor

We analyze constraints on a class of extended technicolor (ETC) models from neutral flavor-changing processes induced by (dimension-six) four-fermion operators. The ETC gauge group is taken to commute with the standard-model gauge group. The models in the class are distinguished by how the left- and right-handed $(L,R)$ components of the quarks and charged leptons transform under the ETC group. We consider $K^{0} - \bar K^0$ and other pseudoscalar meson mixings, and conclude that they are adequately suppressed if the $L$ and $R$ components of the relevant quarks are assigned to the same (fundamental or conjugate-fundamental) representation of the ETC group. Models in which the $L$ and $R$ components of the down-type quarks are assigned to relatively conjugate representations, while they can lead to realistic CKM mixing and intra-family mass splittings, do not adequately suppress these mixing processes. We identify an approximate global symmetry that elucidates these behavioral differences and can be used to analyze other possible representation assignments. Flavor-changing decays, involving quarks and/or leptons, are adequately suppressed for any ETC-representation assignment of the $L$ and $R$ components of the quarks, as well as the leptons. We draw lessons for future ETC model building.Comment: 25 page

Systematic Biases in Parameter Estimation of Binary Black-Hole Mergers

Parameter estimation of binary-black-hole merger events in gravitational-wave data relies on matched filtering techniques, which, in turn, depend on accurate model waveforms. Here we characterize the systematic biases introduced in measuring astrophysical parameters of binary black holes by applying the currently most accurate effective-one-body templates to simulated data containing non-spinning numerical-relativity waveforms. For advanced ground-based detectors, we find that the systematic biases are well within the statistical error for realistic signal-to-noise ratios (SNR). These biases grow to be comparable to the statistical errors at high signal-to-noise ratios for ground-based instruments (SNR approximately 50) but never dominate the error budget. At the much larger signal-to-noise ratios expected for space-based detectors, these biases will become large compared to the statistical errors but are small enough (at most a few percent in the black-hole masses) that we expect they should not affect broad astrophysical conclusions that may be drawn from the data

Long Distance Contribution to KL→ℓ+ℓ−K_L \to \ell^+ \ell^-

We revisit the calculation of the long distance contribution to $K_L \to \mu^+ \mu^-$. We discuss this process within the framework of chiral perturbation theory, and also using simple models for the $K_L \gamma^* \gamma^*$ vertex. We argue that it is unlikely that this mode can be used to extract information on short distance parameters. The process $K_L \to e^+ e^-$ is also long-distance dominated and we find that $B(K_L \to e^+ e^-) \approx 9 \times 10^{-12}$.Comment: References added, one typo corrected. Version to appear in Nuclear Physics

Kaon decays and the flavour problem

After a brief introduction to the so-called flavour problem, we discuss the role of rare K decays in probing the mechanism of quark-flavour mixing. Particular attention is devoted to the formulation of the Minimal Flavour Violation hypothesis, as a general and natural solution to the flavour problem, and to the fundamental role of K -> pi nu nu-bar decays in testing this scenario.Comment: 10 pages, 6 figures, contribution to TH 2002 (Paris, July 2002