The angular distribution of upward-going muons produced by atmospheric neutrinos in the rock below the MACRO detector shows anomalies in good agreement with two flavor vμ → vτ oscillations with maximum mixing and Δm2 around 0.0024 eV2. Exploiting the dependence of magnitude of the matter effect on oscillation channel, and using a set of 809 upward-going muons observed in MACRO, we show that the two flavor vμ → vs oscillation is disfavored with 99% C.L. with respect to vμ → vτ.
|Original language||English (US)|
|Number of pages||8|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|State||Published - Sep 27 2001|
Bibliographical noteFunding Information:
We thank T. Kajita for useful discussions to compare our data to those of SuperKamiokande. We acknowledge the staff of the Laboratori Nazionali del Gran Sasso and the invaluable assistance of the technical staffs of all the participating Institutions. For generous financial contributions we thank the US Department of Energy, the National Science Foundation, and the Italian Istituto Nazionale di Fisica Nucleare: both for direct support and for FAI grants awarded to non-Italian MACRO collaborators.