Clopper-Pearson Bounds from HEP Data Cuts

For the measurement of Ns signals in N events rigorous confidence bounds on the true signal probability pexact were established in a classical paper by Clopper and Pearson [Biometrica 26, 404 (1934)]. Here, their bounds are generalized to the HEP situation where cuts on the data tag signals with probability Ps and background data with likelihood Pb < Ps. The Fortran program which, on input of Ps, Pb, the number of tagged data N and the total number of data N , returns the requested confidence bounds as well as bounds on the entire cumulative signal distribution function, is available on the web. In particular, the method is of interest in connection with the statistical analysis part of the ongoing Higgs search at the LEP experiments. ∗This research was partially funded by the Department of Energy under contract DE-FG02-97ER41022. 1