Separating Signals from Non-Interfering Backgrounds using Probabilistic   Event Weightings
  A common situation in experimental physics is to have a signal which can not be separated from a non-interfering background through the use of any cut. In this paper, we describe a procedure for determining, on an event-by-event basis, a quality factor (Q-factor) that a given event originated from the signal distribution. This Q-factor can then be used as an event weight in subsequent analysis procedures, allowing one to more directly access the true spectrum of the signal. 
M. Williams, M. Bellis and C.A. Meyer