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ID: 494357.0, MPI für Kernphysik / Neutrino Physics
Observation of geo-neutrinos
Authors:
Language:English
Date of Publication (YYYY-MM-DD):2010-04-19
Title of Journal:Physics Letters B
Journal Abbrev.:Phys. Lett. B
Volume:687
Issue / Number:4-5
Start Page:299
End Page:304
Review Status:not specified
Audience:Experts Only
Abstract / Description:Geo-neutrinos, electron anti-neutrinos produced in beta decays of naturally occurring radioactive isotopes in the Earth, are a unique direct probe of our planet's interior. We report the first observation at more than 3$\sigma$ C.L. of geo-neutrinos, performed with the Borexino detector at Laboratori Nazionali del Gran Sasso. Anti-neutrinos are detected through the neutron inverse beta decay reaction. With a 252.6 ton-yr fiducial exposure after all selection cuts, we detected 9.9^{+4.1}_{-3.4}(^{+14.6}_{-8.2}) geo-neutrino events, with errors corresponding to a 68.3%(99.73%) C.L. From the $\ln{\cal{L}}$ profile, the statistical significance of the Borexino geo-neutrino observation corresponds to a 99.997% C.L. Our measurement of the geo-neutrinos rate is 3.9^{+1.6}_{-1.3}(^{+5.8}_{-3.2}) events/(100ton-yr). This measurement rejects the hypothesis of an active geo-reactor in the Earth's core with a power above 3 TW at 95% C.L. The observed prompt positron spectrum above 2.6 MeV is compatible with that expected from european nuclear reactors (mean base line of approximately 1000 km). Our measurement of reactor anti-neutrinos excludes the non-oscillation hypothesis at 99.60% C.L.
External Publication Status:published
Document Type:Article
Affiliations:
Identifiers:URL:http://dx.doi.org/10.1016/j.physletb.2010.03.051
DOI:10.1016/j.physletb.2010.03.051
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