Experimental study of upward-going muons in Kamiokande

Upward-going muons produced in the surrounding rock by high-energy neutrinos from astronomical objects have been searched for using the large underground water Cherenkov detector, Kamiokande. During a total of 1255 days observation, no significant signal was observed from the direction of eight astronomical objects. The 90%-confidence-level (-C.L.) upper limits on upward-going muon fluxes with energy greater than 1.7 GeV are 9.9 x 10/sup -14/ cm/sup -2/s/sup -1/ for Cygnus X-3 and 2.6 x 10/sup -14/ cm/sup -2/s/sup -1/ for LMC X-4. Our observed upward-going muon flux is compared with the calculation of the upward-going muon flux produced by the atmospheric neutrinos to examine the neutrino-oscillation hypothesis. The experimental average upward-going muon flux with energy greater than 1.7 GeV, (2.05 +- 0.18) x 10/sup -13/ cm/sup -2/s/sup -1/sr/sup -1/, is consistent with the theoretical expectation. If ..nu../sub ..mu../left-right-arrow..nu../sub tau/ vacuum oscillations and large mixing angle are assumed, ..delta..m/sup 2/approx. >10/sup -2/ eV/sup 2/ is newly rejected. The 90%-C.L. upper limit on the ..delta..m/sup 2/ for the maximum mixing is found to be ..delta..m/sup 2/ = 0.03 eV/sup 2/ and ..delta..m/sup 2/ = 0.0055 eV/sup 2/, depending on assumptions.