Search for possible neutrino radiative decays during the 2001 total solar eclipse

We present the results of the observations performed in the occasion of the June 21, 2001 total solar eclipse, looking for visible photons emitted trough a possible radiative decay of solar neutrinos. We establish lower limits for the neutrino proper lifetimes larger than 1000 s/eV, for neutrino masses larger than 0.01 eV.Comment: 18 pages, 11 figures, accepted by Astopart. Phys, updated reference

Structural and dielectric behaviour of barium substituted lead zinc niobate

212-219The polycrystalline samples of (Pb1xBax)(Zn1/3Nb2/3)O3 (PBZN) ceramics have been synthesized by the columbite precursor method. X-ray diffraction analysis of PBZN synthesized for x = 0.15, 0.25, 0.35 and 0.50 shows a cubic perovskite phase at room temperature. The changes in the structures are observed with increasing Ba contents in PBZN. The dielectric dispersion of the solid solutions has been studied as a function of temperature in the frequency range 100 Hz-1MHz. The temperature variation of the real components (ƐƐ) at different frequencies of the dielectric permittivity shows a broad maximum. The diffuse peaks in versus T confirm the relaxor behaviour of PBZN. The changes in the relaxor properties of the compounds are found to be compositional dependent. The frequency dependence of Tm in these compounds with barium substitution is modeled using Vogel-Fulcher relation