Determining the flavour content of the low-energy solar neutrino flux

We study the sensitivity of the HELLAZ and Borexino solar neutrino experime nts on discriminating the neutrino species nu (e), <(<nu>)over bar>(e), nu (mu,tau), <(<nu>)over bar>(mu,tau), and nu (s) using the difference in the recoil electron kinetic energy spectra in elastic neutrino-electron scatter ing. We find that one can observe a non-vanishing nu (mu,tau) component in the solar neutrino flux, especially when the nu (e) survival probability is low. Also, if the data turn out to be consistent with nu (e) <----> nu (mu ,tau) oscillations, a <(<nu>)over bar>(e) component can be excluded effecti vely.