Spatial confinement of muonium atoms

TL;DR

This paper demonstrates the spatial confinement of muonium atoms using reflective silica surfaces, enabling advanced experiments and precise spectroscopic measurements of this exotic atomic system.

Contribution

It introduces a novel method for confining muonium atoms in vacuum with high reflection probability, facilitating future high-precision spectroscopic studies.

Findings

Reflection probability on silica surfaces is about 90% at 100 K.

Reflections follow a cosine law, confirming the confinement mechanism.

The technique opens new possibilities for muonium-based experiments.

Abstract

We report the achievement of spatial confinement of muonium atoms (the bound state of a positive muon and an electron). Muonium emitted into vacuum from mesoporous silica reflects between two SiO$_2$ confining surfaces separated by 1 mm. From the data, one can extract that the reflection probability on the confining surfaces kept at 100 K is about 90% and the reflection process is well described by a cosine law. This technique enables new experiments with this exotic atomic system and is a very important step towards a measurement of the 1S-2S transition frequency using continuous wave laser spectroscopy.