by @2qzclust for the 2dF catalog, namely $\gamma=1.58$ and $\gamma=1.56$ for EdS and $\Lambda$ models, respectively. In this way, the comparison with the TPCF at higher redshifts obtained from the 2dF data is equivalent both in term of $r_0$ and $\bar\xi$.

By using all the distances between the quasar-random pairs, we can compute the number of pairs $g(r)dr$ in arbitrarily small bins $dr$ and use it to predict the mean number of quasar-quasar pairs $h(r)dr$ in that interval as

$$h(r)dr=   
{{N_c-1}\over{2N_r}} [1+\xi(r)] g(r)dr\ ,$$

where the correlation function $\xi$ is modeled with a power-law as in Eq.(\[eq:powlaw\])[^2]. In this way, it is possible to use all the distances between the $N_p$ quasar-quasar pairs data to build a likelihood. In particular, the likelihood function ${\cal L}$ is defined as the product of the probabilities of having exactly one pair at each of the intervals $dr$ occupied by the quasar-quasar pairs data and the probability of having no pairs in all other intervals. Assuming a Poisson distribution, one finds $${\cal L}= \prod_i^{N_p} \exp[-h(r)dr] h(r)dr \prod_{j\ne i}   
\exp[-h(r)dr]\ ,$$ where $j$ runs over all the intervals $dr$ where there are no pairs. It is convenient to define the usual quantity $S=-2 \ln {\cal 