Implications for primordial non-Gaussianity (fNL) from weak lensing masses of high-z galaxy clusters

The recent weak-lensing measurement of the dark matter mass of the high-redshift galaxy cluster XMMUJ2235.3-2557 of (8.5 +/- 1.7)x10(14)M(circle dot) at z=1.4, indicates that, if the cluster is assumed to be the result of the collapse of dark matter in a primordial Gaussian field in the standard lambda cold dark matter model, then its abundance should be < 2x10(-3) clusters in the observed area. Here we investigate how to boost the probability of XMMUJ2235.3-2557, in particular, resorting to deviations from Gaussian initial conditions. We show that this abundance can be boosted by factors > 3-10 if the non-Gaussianity parameter f(NL)(local) is in the range 150-200. This value is comparable to the limit for f(NL) obtained by current constraints from the cosmic microwave background. We conclude that mass determination of high-redshift, massive clusters can offer a complementary probe of primordial non-Gaussianity.