Cluster correlation in mixed models

We evaluate the dependence of the cluster correlation length, r(c), on the mean intercluster separation, D-c, for three models with critical matter de nsity, vanishing vacuum energy (Lambda = 0), and COBE normalization: a tilt ed cold dark matter (tCDM) model (n = 0.8) and two blue mixed models with t wo light massive neutrinos, yielding Omega (h) = 0.26 and 0.14 (MDM1 and MD M2, respectively). All models approach the observational value of sigma (8) (and hence the observed cluster abundance) and are consistent with the obs erved abundance of damped Ly alpha systems. Mixed models have a motivation in recent results of neutrino physics; they also agree with the observed va lue of the ratio sigma (8)/sigma (25), yielding the spectral slope paramete r Gamma, and nicely fit Las Campanas Redshift Survey (LCRS) reconstructed s pectra. We use parallel AP3M simulations, performed in a wide box (of side 360 h(-1) Mpc) and with high mass and distance resolution, enabling us to b uild artificial samples of clusters, whose total number and mass range allo w us to cover the same D-c interval inspected through Automatic Plate Measu ring Facility (APM) and Abell cluster clustering data. We find that the tCD M model performs substantially better than n = 1 critical density CDM model s. Our main finding, however, is that mixed models provide a surprisingly g ood fit to cluster clustering data.