Alberto Lusiani (Scuola Normale Superiore and INFN Pisa)
We present the status of the experimental searches for flavour changing neutral current (FCNC) processes where a b hadron decays into light hadrons (X_d, X_s) and two neutrinos. Within the Standard Model, these processes are suppressed and rare, with branching fractions around 5*10^-6. Several New Physics models predict significant enhancements. Recent analyses by the Belle and BaBar collaborations have set several upper limits.