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arXiv · hep-ph/9302292

New Upper Limits on the Tau Neutrino Mass from Primordial Helium Considerations

A. D. Dolgov·I. Z. Rothstein
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Abstract

In this paper we reconsider recently derived bounds on $MeV$ tau neutrinos, taking into account previously unaccounted for effects. We find that, assuming that the neutrino life-time is longer than $O(100~sec)$, the constraint $N_{eff}<3.6$ rules out $ν_τ$ masses in the range $0.5~(MeV)<m_{ν_τ}<35~(MeV)$ for Majorana neutrinos and $0.74~(MeV)<m_{ν_τ}<35~(MeV)$ for Dirac neutrinos. Given that the present laboratory bound is 35 MeV, our results lower the present bound to $0.5$ and $0.74$ for Majorana and Dirac neutrinos respectively.

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A. D. Dolgov, I. Z. Rothstein. 1993-02-23. New Upper Limits on the Tau Neutrino Mass from Primordial Helium Considerations. https://doi.org/10.1103/physrevlett.71.476

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