Normalization of strongly intensive quantities

A special normalization is proposed for strongly intensive quantities used in the study of event-by-event fluctuations in high energy collisions. It ensures that these measures are dimensionless and yields a common scale required for a quantitative comparison of fluctuations of different, in general dimensional, extensive quantities. Namely, the properly normalized strongly intensive quantities assume the value one for fluctuations given by the model of independent particle production and zero in the absence of event-by-event fluctuations.