Harmonizing discovery thresholds and reporting two-sided confidence intervals: a modified Feldman and Cousins method

When searching for new physics effects, collaborations will often wish to publish upper limits and intervals with a lower confidence level than the threshold they would set to claim an excess or a discovery. In this paper a modification to the Feldman-Cousins method is proposed that allows for a transition from one-sided upper confidence limits for null results and a two-sided confidence intervals for non-null results at any given specified threshold chosen to define the observation of a signal, while maintaining exact coverage.