A total of 614 upward throughgoing mouns of minimum energy 1.6 GeV are observed by Super-Kamiokande during 537 detector live days. The measured muon flux is [1.74 ± 0.07(stat) ± 0.02(sys)] × 10-13cm-2s-1sr-1 compared to an expected flux of [1.97 ± 0.44(theor)] × 10-13cm-2s-1sr-1. The absolute measured flux is in agreement with the prediction within the errors. However, the zenith-angle dependence of the observed upward throughgoing muon flux does not agree with no-oscillation predictions. The observed distortion in shape is consistent with the νμ ↔ ντ oscillation hypothesis with sin2 2θ > 0.4 and 1 × 10-3 <1 × 10-1 <δm2 <1 × 10-1 eV2 at 90% confidence level.
|Number of pages||5|
|Journal||Physical Review Letters|
|Publication status||Published - Mar 29 1999|
ASJC Scopus subject areas
- Physics and Astronomy(all)