Letter of Intent: Muonium R&D/Physics Program at the MTA

TL;DR

This paper proposes an R&D program at Fermilab to develop muonium production and measurement techniques, leveraging upcoming upgrades to enable advanced fundamental physics experiments involving muons and symmetry tests.

Contribution

It introduces a novel experimental approach to produce and utilize muonium beams for gravity measurements at Fermilab's existing infrastructure.

Findings

Demonstration of efficient muonium production using superfluid helium

Development of techniques for muonium gravity measurement

Preparation for future high-precision muon experiments

Abstract

With the planned turn-on of the PIP-II 800 MeV superconducting proton linac, Fermilab will potentially become the world's best laboratory at which to carry out fundamental muon measurements, sensitive searches for symmetry violation, and precision tests of theory. In preparation, we propose to develop the techniques that will be needed. An R&D and physics program is proposed at the Fermilab MeV Test Area to use the existing 400 MeV Linac to demonstrate the efficient production of a slow muonium beam using $\mu^+$ stopped in a ~100-$\mu$m-thick layer of superfluid helium, and to use that beam to measure muonium gravity.