CAN A MASS INVERSION SAVE SOLAR-NEUTRINO OSCILLATIONS FROM THE LSND NEUTRINO

In the light of the (nu)over bar (mu)> --> <(nu)over bar (e)> neutrino oscillations which may have been observed at the LSND experiment we e xplore the consequences of two inverted mass schemes where solar neutr ino oscillations occur between nu(e) and nu(tau). One favored LSND val ue, Delta m(2) = 6eV(2), leads to m(nu e) approximate to m(nu tau) app roximate to 2.5 eV and m(nu mu) approximate to 0 so that cosmology can benefit from a recently proposed ''cold plus hot dark matter'' struct ure formation scenario with two equal mass light neutrinos (C nu(2)DM) . Solar neutrino oscillations (nu(e) --> nu(tau)) can occur with one o f the large mixing angle solutions so that a serious conflict with bet a beta decay Majorana mass limits is avoided without invoking Dirac ma sses. However, there is a problem with the SN 1987A signal because of resonant <(nu)over bar (e)> <-> <(nu)over bar (mu)> oscillations which are expected to cause far higher <(nu)over bar (e)> energies at the I MB and Kamiokande II detectors than have been observed. A small value Delta m(2) approximate to 0.5 eV(2) at LSND, which allows for a relati vely large nu(e)-nu(mu) mixing angle without conflicting with the KARM EN and BNL-E776 experiments, would indicate m(nu e) approximate to m(n u tau) approximate to 1.6 eV and m(nu mu) approximate to 1.8 eV. This scheme of C nu(3)DM maintains, and even may improve, the essential cos mological model implications for large-scale structure, leaving no con flict with SN r-process nucleosynthesis.