GeV Neutrino Research Articles

A search for heavy charged and neutral leptons from Z 0 decays

We have searched for charged and neutral leptons. We exclude stable Dirac neutrinos below 42.8 GeV and stable Majorana neutrinos below 34.8 GeV. From a search for unstable neutrinos we exclude masses below 46.4 GeV (Dirac) and below 45.1 GeV (Majorana). We exclude all masses of sequential charged and neutral leptons, except if both masses are larger than 42.8 GeV (for stable Dirac neutrinos). All mass limits correspond to 95% CL.

Observation of μ−e− events in neutrino interactions at 3–30 GeV neutrino energy

The production of μ − e − pairs is studied in interactions of neutrinos with nuclei of heavy freon in the SKAT bubble chamber experiment. A rate of μ − e − pairs to charged current interactions of R μ − e − =(2.5± 1.4 4.3)×10 −4 is found at an average neutrino energy of 10 GeV. The ratio μ − e −/ μ − e + comes out to be μ − e −/ μ − e + = 0.12± 0.08 0.22.

Can scalar neutrinos or massive Dirac neutrinos be the missing mass?

Scalar neutrinos and massive Dirac neutrinos in the mass range 2–20 GeV have been proposed as candidates to provide the dark matter in the halo of our galaxy. If so, the particles are captured inthe Earth with an efficiency of 10 −10 − 10 −7. For Dirac neutrinos more massive than about 9 GeV and scalar neutrinos more massive than abour 12 GeV, enough are captured to produce an observable neutrino flux at the surface of the Earth (∼ 10 −2 cm −2 s −1 for sneutrinos and ∼ 1.4 × 10 −3 cm −2 s −1 for Dirac neutrinos), several orders of magnitude above atmospheric background and above what is observed. Hence stable scalar neutrinos of mass 12–20 GeV or Dirac neutrinos of mass 9–20 GeV cannot be the dominant component of the halo.

A measurement of the ratio of longitudinal and transverse structure functions in neutrino interactions between 30 and 200 GeV

A new measurement of the ratio R = σ L/ σ T of longitudinal and transverse structure functions in neutrino interactions on iron between 30 and 190 GeV neutrino energy is reported. The result is given as a function of the scale parameter x and the inelasticity ν of the interaction. The average value is R = 0.10 ± 0.07 around ν ≈ 50 GeV and is in accordance with a prediction from the QCD theory.

Pion and strange particle production by 1 GeV neutrinos

Estimates are made of cross-sections for the production of pions or strange particles by high-energy neutrinos incident on nuclei. At 1 GeV the production of pions via the (33) resonance is found to augment the total cross-section by about 50%.