0000000000620802
AUTHOR
J. R. Leslie
Direct evidence for neutrino flavor transformation from neutral-current interactions in the Sudbury Neutrino Observatory
Observations of neutral current neutrino interactions on deuterium in the Sudbury Neutrino Observatory are reported. Using the neutral current, elastic scattering, and charged current reactions and assuming the standard 8B shape, the electron-neutrino component of the 8B solar flux is 1.76 +/-0.05(stat.)+/-0.09(syst.) x10^6/(cm^2 s), for a kinetic energy threshold of 5 MeV. The non-electron neutrino component is 3.41+/-0.45(stat.)+0.48,-0.45(syst.) x10^6/(cm^2 s), 5.3 standard deviations greater than zero, providing strong evidence for solar electron neutrino flavor transformation. The total flux measured with the NC reaction is 5.09 +0.44,-0.43(stat.)+0.46,-0.43(syst.)x10^6/(cm^2 s), consi…
High-resolution γ-ray spectroscopy: a versatile tool for nuclear β-decay studies at TRIUMF-ISAC
High-resolution γ-ray spectroscopy is essential to fully exploit the unique, high-quality beams available at the next generation of radioactive ion beam facilities such as the TRIUMF isotope separator and accelerator (ISAC). The 8π spectrometer, which consists of 20 Compton-suppressed HPGe detectors, has recently been reconfigured for a vigorous research programme in weak interaction and nuclear structure physics. With the addition of a variety of ancillary detectors it has become the world's most powerful device dedicated to β-decay studies. This paper provides a brief overview of the apparatus and highlights from recent experiments.
Measurement of day and night neutrino energy spectra at SNO and constraints on neutrino mixing parameters
The Sudbury Neutrino Observatory (SNO) has measured day and night solar neutrino energy spectra and rates. For charged current events, assuming an undistorted $^8$B spectrum, the night minus day rate is $14.0% \pm 6.3% ^{+1.5}_{-1.4}%$ of the average rate. If the total flux of active neutrinos is additionally constrained to have no asymmetry, the $\nu_e$ asymmetry is found to be $7.0% \pm 4.9% ^{+1.3}_{-1.2}%$. A global solar neutrino analysis in terms of matter-enhanced oscillations of two active flavors strongly favors the Large Mixing Angle (LMA) solution.