Emulsion Spectrometer Research Articles

Cross sections for charm production by neutrinos

The production of charmed particles has been measured using a hybrid emulsion spectrometer in the Fermilab wide-band neutrino beam. The relative cross section for charged current charmed particle production is σ( v → μ −c)/ σ( v → μ −) = 6.5 ± 1.9 1.8%, and the energy dependence of the cross section is presented. One event with charm pair production was observed. A limit of σ(v → μ c c)/σ(v → μ c) < 6% (90% CL ) is found for the ratio of charged current pair and single charm production.

New Result for the Lifetime of theD0Meson

In an experiment measuring charmed-particle lifetimes with a hybrid emulsion spectrometer, 1248 neutrino and antineutrino interactions produced by the wide-band beam at Fermi National Accelerator Laboratory have been located. Twenty-one candidates for the decay of neutral charmed particles are found. The lifetime for the D0 based on the sixteen constrained events of this sample is measured to be 2.3−0.5+0.8×10−13 sec.Received 28 December 1981DOI:https://doi.org/10.1103/PhysRevLett.48.844©1982 American Physical Society

Upper Limits toνμ−ντOscillation andνμ−τCoupling

A search for τ lepton production in a sample of 1241 neutrino interactions with use of a hybrid emulsion spectrometer in the Fermilab wide-band neutrino beam is reported. No such events are seen and an upper limit to the νμ−τ coupling of 0.63% (90% C.L.) is set. For νμ−ντ oscillations this sets a limit of |mνμ2−mντ2|<3.0 eV2 (90% C.L.) for maximum mixing.Received 11 August 1981DOI:https://doi.org/10.1103/PhysRevLett.47.1694©1981 American Physical Society

Rigidity spectrum of Z greater than or equal to 3 cosmic-ray nuclei in the range 4-285 GV and a search for cosmic antimatter

A measurement, using the magnetic emulsion spectrometer system, of the differential rigidity spectrum of Z greater than or equal to 3 nuclei of the galactic cosmic radiation is presented. The system was flown on Aug. 22, 1969, from Palestine, Texas. The instrument floated above 125,000 feet for eight hours. The data in the rigidity range 8-285 GV can be represented by a power-law spectrum in rigidity, J(rho) = A rho to the minus gamma power, with the exponent gamma = 2.6 plus or minus 0.10. The spectrum in the range 15-285 GV is also described by the same exponent, gamma = 2.6 plus or minus 0.25. The data below 8 GV cannot be described by the same power law without invoking solar modulation. A set of nonunique parameters for modulation are given. Upper limit for the fraction of antimatter in the rigidity range 4-125 GV is .005 with 95% confidence limit.