 Here formula_6 and formula_7 are parameters of the distribution and

where formula_9 and formula_10 are the cumulative distribution and probability density functions of the standard normal distribution, respectively.The cumulative distribution function (cdf) of the ARGUS distribution is

Parameter "c" is assumed to be known (the kinematic limit of the invariant mass distribution), whereas "χ" can be estimated from the sample "X"1, …, "X""n" using the maximum likelihood approach.The estimator is a function of sample second moment, and is given as a solution to the non-linear equation

The solution exists and is unique, provided that the right-hand side is greater than 0.4; the resulting estimator formula_13 is consistent and asymptotically normal.