Radon background in liquid xenon detectors

The radioactive daughters isotope of 222Rn are one of the highest risk contaminants in liquid xenon detectors aiming for a small signal rate. The noble gas is permanently emanated from the detector surfaces and mixed with the xenon target. Because of its long half-life 222Rn is homogeneously distributed in the target and its subsequent decays can mimic signal events. Since no shielding is possible this background source can be the dominant one in future large scale experiments. This article provides an overview of strategies used to mitigate this source of background by means of material selection and on-line radon removal techniques

Rational Actors in Balancing Markets: a Game-Theoretic Model and Results

Guided by game theory we develop a model to explain behavioral equilibria under uncertainty and interaction with the spot market on balancing markets. We offer some insights for the general model and derive explicit solutions for a specific model in which the error distributions and pricing function are given. The most interesting conclusions are the unique existence of an equilibrium and that no participant acts contrary to the aggregate market (either all market participants buy or sell power) and all strategies are, normalized properly, equal (which is rather counterintuitive). Furthermore the aggregate behavior is a stochastic process varying around its own variance.game theory, nash equilibrium, regulated energy market, balancing power

Meta Analysis of Empirical Deterrence Studies: an explorative contest

A sample of 200 studies empirically analyzing deterrence in some way is evaluated. Various methods of data mining (stepwise regressions, Extreme Bounds Analysis, Bayesian Model Averaging, manual and naive selections) are used to explore different influences of various variables on the results of each study. The preliminary results of these methods are tested against each other in a competition of methodology to evaluate their performance in forecasting and fitting the data and to conclude which methods should be favored in an upcoming extensive meta-analysis. It seems to be the case that restrictive methods (which select fewer variables) are to be preferred when predicting data ex ante, and less parsimonious methods (which select more variables) when data has to be fitted (ex post). In the former case forward stepwise regression or Bayesian Model Selection perform very well, whereas backward stepwise regression and Extreme Bounds Analysis are to be preferred in the latter case.meta analysis, data mining, deterrence, criminometrics

Rough set methodology in meta-analysis - a comparative and exploratory analysis

We study the applicability of the pattern recognition methodology "rough set data analysis" (RSDA) in the field of meta analysis. We give a summary of the mathematical and statistical background and then proceed to an application of the theory to a meta analysis of empirical studies dealing with the deterrent effect introduced by Becker and Ehrlich. Results are compared with a previously devised meta regression analysis. We find that the RSDA can be used to discover information overlooked by other methods, to preprocess the data for further studying and to strengthen results previously found by other methods.Rough Data Set, RSDA, Meta Analysis, Data Mining, Pattern Recognition, Deterrence, Criminometrics

D_{sJ}(2860) as the first radial excitation of the D_{s0}^*(2317)

A coupled-channel model previously employed to describe the narrow $D_{s0}^*$(2317) and broad $D_0^*$(2400) charmed scalar mesons is generalized so as to include all ground-state pseudoscalar-pseudoscalar and vector-vector two-meson channels. All parameters are chosen fixed at published values, except for the overall coupling constant, which is fine-tuned to reproduce the $D_{s0}^*$(2317) mass. Thus, the radial excitations $D_{s0}^*$(2850) and $D_0^*$(2740) are predicted, both with a width of about 50 MeV. The former state appears to correspond to the new $D_{sJ}$(2860) resonance decaying to $DK$ announced by BABAR in the course of this work. Also the $D_0^*$(2400) resonance is roughly reproduced, though perhaps with a somewhat too low central resonance peak.Comment: Plain LaTeX, 4 pages, 2 Postscript figures; v2: REVTeX, 4 pages, introduction expanded, "Note added in proof" and references added, figures with more detail and improved quality, version accepted for publication in Physical Review Letter