Probing the solar MSW large mixing angle solution with terrestrial (ν)over-bar-e from European nuclear reactors with BOREXINO

Electron anti-neutrinos ((nu)over-bar(e)) emitted from distant (similar-to 800 km) nuclear reactors will be measurable with the BOREXINO detector at the Gran Sasso Underground Laboratory. From this signal neutrino oscillation parameters can be assessed for Delta m(2) greater-than 10(-6)eV(2) and sin(2) 2- greater-than 0.3. In particular one of the currently favoured Delta m(2)-sin(2) 2- parameter regions, i.e. the large mixing angle MSW solution which is proposed in order to resolve the solar neutrino problem, can be tested for the first time in a terrestrial laboratory experiment. The impact of nonreactor (nu)over-bar(e)'s, in particular the signal of geo-physical neutrinos and potential backgrounds are discussed.