CHORUS results neutrino oscillations

The CHORUS experiment aims to detect neutrino oscillation nu /sub mu / to nu /sub tau /, especially at the dark matter mass scale ~10 eV. The CHORUS apparatus has been installed in the CERN West Area and exposed to the SPS Wide Band neutrino beam for about 150 days per year from May '94 to November '97. The emission stacks were replaced every 2-year period and developed. A limit on nu /sub mu / to nu /sub e/ oscillation has recently been published from the analysis of a subsample of neutrino interactions taken in '94 and '95. This paper contains an update of the result using the statistics taken in '96. At present the nu /sub tau / interaction search has been performed with 66,304 "1 mu " events and 7,081 "O mu " events in nuclear emulsion. No neutrino oscillation signal was found, which translates into a mixing angle limit sin/sup 2/(2 theta )<or=1.3*10/sup -3 /(900.000554330žL at large Delta m/sup 2/, of the order of 100 eV/sup 2/). (7 refs).