to the onset of minijets. It is definitely an indication of new physics.

In Figure 9 we plot the charged particle multiplicity distribution for $p\bar{p}$ collisions at $\sqrt{s} = 900$ GeV from the UA5 collaboration [@ua5]. For energies less then 500 GeV it was found that the distribution could be well described by a negative binomial distribution of the form $$\begin{aligned}
P_n (\bar{n}, k) =
\left( \begin{array}{c} n+k-1\\ k-1 \end{array} \right)
\left[ \frac{ \bar{n} / k }{ 1+(\bar{n} / k)} \right]^n
\frac{1}{[1+(\bar{n} / k)]^k} \, .
\label{nbd}\end{aligned}$$ The parameter $k$ characterizes the width of the distribution. For $k
\rightarrow \infty$ we recover a Poisson distribution, the distribution with the smallest width. One can see from the figure that at 900 GeV a single negative binomial (NBD) cannot describe the data anymore. A double negative binomial (DNBD) of the form discussed in eq. (\[double\]) on the other hand describes it very well. The question remains to what extent a similar analysis might be able to reveal rare events of quark–gluon plasma production at AGS.

A rough criteria for the observability of such structure in distributions of the form (\[double\]) is $$\begin{aligned}
\frac{2}{\sqrt{N_{\rm bin}}} P_{N_{\rm qg}}^{\rm had} =
q P_{N_{\rm qg}}^{\rm qg} 