arXiv subjects

Ilya Narsky

Publications and source records attributed to Ilya Narsky.

3 recordsLinked to original sources

arXiv2003

Estimation of Goodness-of-Fit in Multidimensional Analysis Using Distance to Nearest Neighbor

A new method for calculation of goodness of multidimensional fits in particle physics experiments is proposed. This method finds the smallest and largest clusters of nearest neighbors for observed data points. The cluster size is used to estimate the goodness-of-fit and the cluster location provides clues about possible problems with data modeling. The performance of the new method is compared to that of the likelihood method and Kolmogorov-Smirnov test using toy Monte Carlo studies. The new method is applied to estimate the goodness-of-fit in a B->Kll analysis at BaBar.

physics.data-an↗

arXiv2000

Expected Coverage of Bayesian Confidence Intervals for the Mean of a Poisson Statistic in Measurements with Background

Expected coverage and expected length of 90% upper and lower limit and 68.27% central intervals are plotted as functions of the true signal for various values of expected background. Results for several objective priors are shown, and formulas for calculation of confidence intervals are obtained. For comparison, expected coverage and length of frequentist intervals constructed with the unified approach of Feldman and Cousins and a simple classical method are also shown. It is assumed that the expected background is accurately known prior to performing an experiment. The plots of expected coverage and length are provided for values of signal and background typical for particle experiments with small numbers of events.

hep-ex↗

arXiv1999

Estimation of Upper Limits Using a Poisson Statistic

Bayesian, classical, and extended maximum likelihood approaches to estimation of upper limits in experiments with small numbers of signal events are surveyed. The discussion covers only experiments whose outcomes are well described by a Poisson statistic. A new approach, based on the statistical significance of a signal rather than on the number of events in the signal region, is proposed. A toy model and an example of a recent search for the lepton number violating decay $τ\toμγ$ are used to illustrate application of the discussed techniques.

hep-ex↗