In physics, the ARGUS distribution, named after the particle physics experiment ARGUS,[1] is the probability distribution of the reconstructed invariant mass of a decayed particle candidate in continuum background[clarification needed].

The probability density function (pdf) of the ARGUS distribution is: for

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

Here parameters c, χ, p represent the cutoff, curvature, and power respectively.

[2][circular reference] The variance is: p = 0.5 gives a regular ARGUS, listed above.