correlations at large interparticle distances. In terms of the cluster expansion this screening appears through significant higher-order contributions. In order to avoid large higher-order contributions, and at the same time to effectively describe the screening effect, the range of the tensor correlation function — more precisely, the “correlation volume" $I_{\vartheta}^{(S,T)}$ [@RHP2005] — is restricted during the parameterization procedure. Restricting the range of the tensor correlator has another important function, namely to ensure that only state-independent, short-range correlations are described by the UCOM. By varying the correlation volumes — the only parameters entering the formalism — a family of correlators and respective correlated interactions are obtained.

The question is then how to optimize these parameters in order to best describe the screening effect and the separation of the two types of correlations. As demonstrated in Ref. [@RHP2005], this can be done with the help of exact few-body calculations. In particular, applications within the no-core shell model showed that for the Argonne V18 potential the value $I_{\vartheta}^{(1,0)}=0.09$ fm$^3$ leads to the best description of binding energies in [$^{3}$[H]{}]{} and [$^{4}$[He]{}]{}. For this choice of tensor correlator range the missing genuine three-nucleon interaction and the ommitted higher-order terms of the cluster expansion of 