New lower limits on the lifetime of heavy neutrino radiative decay

Abstract

a b s t r a c tThe data collected during the 2006 total solar eclipse are analyzed in the search for signals produced by a hypothetical radiative decay of heavy neutrinos. In the absence of the expected light pattern, we extract lower limits for the heavy neutrino components proper lifetime. The present analysis restricts to the direct hierarchy hypothesis (m 3 ) m 2 > m 1 ). The quality of the data in terms of reached sensitivity suggests that those are the best limits obtainable using this technique.

Neutrino Oscillations in the Atmospheric Parameter Region: From the Early Experiments to the Present

“…The indications from experiments and from cosmology are that neutrinos are either stable or long lived [62]. Specific experiments which searched for radiative solar neutrino decays during total solar eclipses yielded ] > 10 − 10 9 s depending on the ] 1 mass [63].…”

“…The radiative decay modes allowed for massive neutrinos are ] 2 → ] 1 + and ] 3 → ] 2,1 + [62]. A direct experimental limit comes from the 2006 total solar eclipse in the Libya Sahara desert [63]. For the ] 2 → ] 1 + radiative decay the 95% CL lower lifetime limits are in the range 10 s ÷10 9 s for neutrino masses 10 −4 eV < 1 < 0.1 eV [63].…”

“…A direct experimental limit comes from the 2006 total solar eclipse in the Libya Sahara desert [63]. For the ] 2 → ] 1 + radiative decay the 95% CL lower lifetime limits are in the range 10 s ÷10 9 s for neutrino masses 10 −4 eV < 1 < 0.1 eV [63]. A similar limit was obtained for the ] 3 → ] 2,1 + decay, but the limit is tentative since it depends on the mixing angle 13 which was not known at that time.…”

Lower limits on the lifetime of massive neutrino radiative decay from the 2006 total solar eclipse

“…In this paper we report on the observations performed in occasion of the 29 March 2006 TSE, from Waw an Namos, Libya (Cecchini et al, 2011). The hypothesis of the inverted mass neutrino hierarchy is considered for the first time in such a contest.…”

“…Very strong limits were inferred from cosmological or astrophysical considerations, but such limits are indirect and rather speculative. Some of them are shortly reviewed in Cecchini et al (2011).…”