Neutrino Signals in Electron-Capture Storage-Ring Experiments

Avraham Gal

doi:10.3390/sym8060049

Abstract

Neutrino signals in electron-capture decays of hydrogen-like parent ions P in storage-ring experiments at GSI are reconsidered, with special emphasis placed on the storage-ring quasi-circular motion of the daughter ions D in two-body decays P → D + ν e . It is argued that, to the extent that daughter ions are detected, these detection rates might exhibit modulations with periods of order seconds, similar to those reported in the GSI storage-ring experiments for two-body decay rates. New dedicated experiments in storage rings, or using traps, could explore these modulations.

Highlights

We derived a nonvanishing oscillation frequency that a daughter ion moving in a storage ring should exhibit when disentangled by the action of the guiding external magnetic field from the electron-neutrino produced in the two-body Electron capture (EC) decay of a parent ion coasting in the storage ring
The precise value of the period Tosc given under idealized conditions by Equation (23) depends sensitively on the extent to which the motion of the daughter ion, incorporating its D j components, keeps coherent under given experimental constraints, primarily determined by the electron cooling system performance
Daughter-ion oscillations in storage-ring circular motion, as discussed above, do not contradict any of the assertions made in Refs. [8,9,10,11,12,13,14,15] that oscillations cannot show up in parent-ion P decay rates or in daughter-ion D appearance rates

Summary

Introduction

Provided the answer to the question posed above is positive, meaning that some coherence is sustained, it is shown in Sections 2.2 and 2.3 that the time evolution of daughter ions in their storage-ring quasi-circular confined motion gives rise to modulations with angular frequency close to that given in Equation (2) and thereby close to that reported by the GSI experiments. Such modulations do not arise in rectilinear two-body decays [17]. The weight with which daughter ions affect the decay-rate measurement could be varied and thereby evaluated

Daughter-Ion Oscillations in Two-Body EC

Center-of-Mass Oscillation Expressions

Laboratory Frame Oscillation Expressions

Conclusions