M. J. Murtagh

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.

Total cross sections forνμnandνμpcharged-current interactions in the 7-foot bubble chamber

The total cross sections for ..nu../sub ..mu../n and ..nu../sub ..mu../p charged-current interactions and their ratio R = sigma/sub T/(..nu..n)/sigma/sub T/(..nu..p) have been measured as a function of neutrino energy from 0.4 to 10 GeV. The experiment is performed using the BNL 7-foot deuterium bubble chamber exposed to the Alternating Gradient Synchrotron wide-band neutrino beam. The absolute values of the cross sections are normalized to the quasielastic scattering (..nu../sub ..mu../n..--> mu../sup -/p) cross section. Above 1.6 GeV the data are consistent with the quark-parton model. We find that sigma/sub T/(..nu..n)/E/sub ..nu../ = (1.07 +- 0.05) x 10/sup -38/, sigma/sub T/(..nu..p)/E/sub ..nu../ = (0.54 +- 0.04) x 10/sup -38/, and sigma/sub T/(..nu..N)/E/sub ..nu../ = (0.80 +- 0.03) x 10/sup -38/ cm/sup 2//GeV for = 3.2 GeV, and R = 1.95 +- 0.10 for = 3.7 GeV.

Total Cross-sections for Muon-neutrino

The total cross sections for ..nu../sub ..mu../n and ..nu../sub ..mu../p charged-current interactions and their ratio R = sigma/sub T/(..nu..n)/sigma/sub T/(..nu..p) have been measured as a function of neutrino energy from 0.4 to 10 GeV. The experiment is performed using the BNL 7-foot deuterium bubble chamber exposed to the Alternating Gradient Synchrotron wide-band neutrino beam. The absolute values of the cross sections are normalized to the quasielastic scattering (..nu../sub ..mu../n..--> mu../sup -/p) cross section. Above 1.6 GeV the data are consistent with the quark-parton model. We find that sigma/sub T/(..nu..n)/E/sub ..nu../ = (1.07 +- 0.05) x 10/sup -38/, sigma/sub T/(..nu..p)/E/sub ..nu../ = (0.54 +- 0.04) x 10/sup -38/, and sigma/sub T/(..nu..N)/E/sub ..nu../ = (0.80 +- 0.03) x 10/sup -38/ cm/sup 2//GeV for = 3.2 GeV, and R = 1.95 +- 0.10 for = 3.7 GeV.

N

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.

and Muon-neutrino

An analysis of 168 quasi-elastic neutrino interactions νn → μ - p in deuterium yields a value of \({M_A} = .76_{ - .40}^{ + .14}\) GeV for the axial vector mass.

P

In this talk are presented preliminary results on the 7′ Bubble Chamber ν Experiment concerning exposures in H2 and D2, with a yield of 850 ν interactions; in particular we analyze 10 charged current strange particle events, that provide a cross section ratio to non strange particle interactions of .04±.02 at our energies.

Charged Current Interactions in the 7-ft Bubble Chamber

The total cross sections for ..nu../sub ..mu../n and ..nu../sub ..mu../p charged-current interactions and their ratio R = sigma/sub T/(..nu..n)/sigma/sub T/(..nu..p) have been measured as a function of neutrino energy from 0.4 to 10 GeV. The experiment is performed using the BNL 7-foot deuterium bubble chamber exposed to the Alternating Gradient Synchrotron wide-band neutrino beam. The absolute values of the cross sections are normalized to the quasielastic scattering (..nu../sub ..mu../n..--> mu../sup -/p) cross section. Above 1.6 GeV the data are consistent with the quark-parton model. We find that sigma/sub T/(..nu..n)/E/sub ..nu../ = (1.07 +- 0.05) x 10/sup -38/, sigma/sub T/(..nu..p)/E/sub ..nu../ = (0.54 +- 0.04) x 10/sup -38/, and sigma/sub T/(..nu..N)/E/sub ..nu../ = (0.80 +- 0.03) x 10/sup -38/ cm/sup 2//GeV for = 3.2 GeV, and R = 1.95 +- 0.10 for = 3.7 GeV.

Recent results from neutrino interactions in heavy neon

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.

Quasi-Elastic Neutrino Scattering and the Axial Vector Form Factor

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.

7 ft. bubble chamber ν experiment at Brookhaven National Laboratory

Ten strange particles have been observed in a total of 1086 charged current neutrino interactions obtained in the analysis of 482,000 pictures taken in the Brookhaven Cryogenic 7′ Bubble Chamber filled with hydrogen and deuterium. Details of these events are presented together with rates for associated strange particle and ΔS = ± ΔQ production in neutrino interactions.