Improved Search for Heavy Neutrinos in the Decay $\pi \to e\nu$

Abstract

A search for massive neutrinos has been made in the decay $\pi \to e^{+}\nu$. No evidence was found for extra peaks in the positron energy spectrum indicative of pion decays involving massive neutrinos ($\pi \to e^{+}{\nu }_h$). Upper limits (90 \% C.L.) on the neutrino mixing matrix element $|U_{ei}{|}^2$ in the neutrino mass region 60--135 MeV/$c^2$ were set, which are %representing an order of magnitude improvement over previous results.

References in corpus (4)

• Global Constraints on a Heavy Neutrino
• pi/K -> e nu branching ratios to O(e^2 p^4) in Chiral Perturbation Theory
• Mixing of Active and Sterile Neutrinos
• Detector for measuring the ${\pi }^{+}\to e^{+}{\nu }_e$ branching fraction

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