Search for Neutral Heavy Leptons in Neutrino - Nucleon Interactions at the FNAL Tevatron

Abstract

The search for Neutral Heavy Leptons (NHL) ha the Neutrino-Nucleon ($\nu$-N) interactions has been conducted using the CCFR Detector and the Fermilab Quad Triplet Beam. (FNAL-E744 and FNAL-E770). No evidence for NHL was found in the charged current decay channel, NHL$\to \mu^-$ + X. NHL with masses between 0.5 and 3.0 $GeV /c^{2}$ were excluded for coupling to muons below 1 to $10^{-4}$ of Fermi strength, depending on the NHL mass. An excess of 5.2 +/· 2.3 NHL candidates, in the neutral current decay channel, NHL $\to \nu$ + X, was found for events with the separation between the production vertex and the decay vertex greater than 2.3 meters. No evidence for NHL was found in the neutral current decay channel, NHL$ \to \nu$ +X for events with the separation between the production vertex and the decay vertex between 0.6 meters and 2.3 meters. NHL with masses between 0.5 and 2.0 $GeV /c^{2}$ were excluded for coupling to muon neutrinos below 1 to 5 x $10^{-4}$ of Fermi strength, depending on the NHL mass.