COMPARING AND CONTRASTING THE NU(MU)-]NU(TAU) AND NU(MU)-]NU(S) SOLUTIONS TO THE ATMOSPHERIC NEUTRINO PROBLEM WITH SUPERKAMIOKANDE DATA - ART. NO. 013006

The nu(mu) --> nu(tau) and nu(mu) --> nu(s) solutions to the atmospher ic neutrino problem are compared with SuperKamiokande data. The differ ences between these solutions due to matter effects in the Earth are c alculated for the ratio of mu-like to e-like events and for up-down fl ux asymmetries. These quantities are chosen because they are relativel y insensitive to theoretical uncertainties in the overall neutrino flu x normalization and detection cross sections and efficiencies. A chi(2 ) analysis using these quantities is performed yielding 3 sigma ranges which are approximately given by (0.725 - 1.0, 4 X 10(-4) - 2 X 10(-2 ) eV(2)) and (0.74 - 1.0, 1 X 10(-3) - 2 X 10(-2) eV(2)) for (sin(2)2 theta, Delta m(2)) for the nu(mu) --> nu(tau) and nu(mu) --> nu(s) sol utions, respectively. Values of Delta m(2) smaller than about 2 X 10(- 3) eV(2) are disfavored for the nu(mu) --> nu(s) solution, suggesting that future long baseline experiments should see a positive signal if this scenario is the correct one. [S0556-2821(98)00913-8].