R. Hylton

Dilepton production by neutrinos in neon

In an exposure of the Fermilab 15-ft bubble chamber filled with a heavy neon-hydrogen mixture to a broadband neutrino beam, we have observed 81 dilepton events of the type ..nu../sub ..mu../ + Ne ..-->.. ..mu../sup -/ + e/sup +/ + .... This corresponds to (0.5 +- 0.15) % of the total charged-current neutrino interactions. A total of fifteen neutral strange-particle decays (K/sub s//sup 0/ ..-->.. ..pi../sup +/..pi../sup -/, ..lambda../sup 0/ ..-->.. p..pi../sup -/) were found in these dilepton events. When corrected for detection efficiencies and unobservable strange particles, this is consistent with production of approximately one strange particle per event.

Recent results from neutrino interactions in heavy neon

Recent results are reported from an analysis of 100,000 pictures of the Fermilab 15 ft bubble chamber filled with heavy neon and exposed to the double horn focused, wideband ..nu../sub ..mu../ beam. There were 164 dilepton (..mu../sup -/e/sup +/) events with 33 vees found in good agreement with the GIM model of charm production. Also observed was the production of the charmed D/sup 0/ meson, followed by the decay D/sup 0/ ..-->.. K/sup 0/..pi../sup +/..pi../sup -/, at a rate of (0.7 +- 0.2)% of all charged current events. From a subsample of film, four events were found of the purely leptonic neutrino--electron elastic scattering process.

Search for Neutrino Oscillations at Fermilab

In this brief presentation I will discuss the results to date of the search for neutrino oscillations by the BNL-Columbia collaboration at Fermilab. The experiment was particularly sensitive to the transformation ν µ →ν e and ν µ → ν τ. The technique utilized the FNAL 15’ cryogenic bubble chamber filled with a hydrogen-neon mixture. The pertinent properties of this detector are the weight of 30 tons, radiation length l R = 40cm and interaction length l I = 125cm. One therefore has reasonable event rate, electron and hadron detection. 400 GeV protons were utilized in a standard, broad band, horn focused, neutrino beam to produce −1 event per picture. The distance from the point of creation of neutrinos to their detection is 1.2km and the average energy of the neutrinos is 25 GeV, with a spectrum that ranges from 5 GeV to 150 GeV. The results I will report on involve an accumulation of 100,000 charge current events ν µ + N→ µ + anything, and 800 observed events including a single electron (e). For the benefit of those individuals with a short attention span, I will now give the results.

Dilepton Production by Neutrinos in Neon

We present preliminary results on dilepton production in the 15-ft bubble chamber filled with heavy neon exposed to a wideband neutrino beam at the Fermi National Accelerator Laboratory. The results are preliminary in the sense that more events of this type will be accumulated as the analysis of the present exposure progresses, and further exposures at Fermilab, intended to triple our data sample, are planned in the near future. The numbers presented in this report are our best numbers at the time of writing (October 1976), which are about twice those actually presented at the conference in Aachen.