Neutrino effects in two-body electron-capture measurements at GSI

TL;DR

This paper investigates the oscillatory behavior observed in electron capture rates at GSI, proposing that neutrino spin precession, rather than neutrino mass differences, may explain the phenomenon, with implications for neutrino magnetic moments.

Contribution

It challenges the neutrino mass interpretation of GSI oscillations and suggests a novel explanation involving neutrino spin precession in magnetic fields.

Findings

GSI oscillations may be due to neutrino spin precession, not mass differences.

Proposed scenario requires a neutrino magnetic moment below current experimental limits.

Implications for neutrino magnetic properties and detection methods.

Abstract

Oscillatory behavior of electron capture rates in the two-body decay of hydrogen-like ions into recoil ions plus undetected neutrinos, with a period of approximately 7 s, was reported in storage ring single-ion experiments at the GSI Laboratory, Darmstadt. Ivanov and Kienle [PRL 103, 062502 (2009)] have relegated this period to neutrino masses through neutrino mixing in the final state. New arguments are given here against this interpretation, while suggesting that these `GSI Oscillations' may be related to neutrino spin precession in the static magnetic field of the storage ring. This scenario requires a Dirac neutrino magnetic moment six times smaller than the Borexino solar neutrino upper limit 0.54 x 10E(-10) of the Bohr magneton [PRL 101, 091302 (2008)], and its consequences are explored.