R. Foot et al., CONFRONTING SOLUTIONS TO THE ATMOSPHERIC NEUTRINO ANOMALY INVOLVING LARGE-ANGLE NU(MU)-]NU(E) OSCILLATIONS WITH SUPERKAMIOKANDE AND CHOOZ, Physics letters. Section B, 433(1-2), 1998, pp. 82-87
Neutrino oscillation scenarios involving large angle mu(nu) --> nu(e)
oscillations are disfavoured in the parameter range Delta m(2)/eV(2) g
reater than or similar to 10(-3) by recent results from the CHOOZ reac
tor-based <(nu)over bar>(e), disappearance experiment. For this reason
we extend our previous work on up-down asymmetries for various oscill
ation scenarios by computing up-down asymmetries and the R ratio for t
he entire range of interest of Delta m(2). Matter effects in the Earth
play a crucial role. We perform a chi(2) fit to the data. We find tha
t, because of the matter effect, the three-flavour maximal mixing mode
l provides a reasonable fit to SuperKamiokande and CHOOZ data provided
that the relevant Delta m(2) is in the range 4 X 10(-4) less than or
similar to Delta m(2)/eV(2) less than or similar to 1.5 X 10(-3) (C) 1
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