Limits on the mixing of tau neutrino to heavy neutrinos

Limits at 90% c.l. on the square of the mixing strength \U-tau4\(2) between v(tau) and a mostly isosing let heavy neutrino with mass in the range 10-290 MeV/c(2) are reported. The results were derived using the negative result of a search for neutral particles decaying into two electrons conducted by the CHARM Collaboration in a neutrino beam dump experiment. Upper limits, congruent to10(-4) were obtained for neutrino masses larger than 160 MeV/c(2). (C) 2002 Elsevier Science B.V. All rights reserved.