Bunching parameter
In statistics as applied in particular in particle physics, when fluctuations of some observables are measured, it is convenient to transform the multiplicity distribution to the bunching parameters:
where ![P_n](/Images/godic/202501/02/9b34c48707062a07e6c080655df4337f3522.png")
is probability of observing
![n](/Images/godic/202501/02/7b8b965ad4bca0e41ab51de7b31363a13522.png")
objects inside of some phase space regions.
The bunching parameters measure deviations of
the multiplicity distribution
from a Poisson distribution, since
for this distribution