Measuring antimatter gravity with muonium
1 Illinois Institute of Technology, Chicago, Illinois 60616, USA
2 Paul Scherrer Institute, Villigen, Switzerland
3 ETH, Zürich, Switzerland
4 Argonne National Laboratory, Argonne, Illinois 60439, USA
5 Harvard Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA
6 also at Muons, Inc., Batavia, Illinois 60510, USA
a e-mail: firstname.lastname@example.org
Published online: 29 May 2015
The gravitational acceleration of antimatter, ḡ, has never been directly measured and could bear importantly on our understanding of gravity, the possible existence of a fifth force, and the nature and early history of the universe. Only two avenues for such a measurement appear to be feasible: antihydrogen and muonium. The muonium measurement requires a novel, monoenergetic, low-velocity, horizontal muonium beam directed at an atom interferometer. The precision three-grating interferometer can be produced in silicon nitride or ultrananocrystalline diamond using state-of-the-art nanofabrication. The required precision alignment and calibration at the picometer level also appear to be feasible. With 100 nm grating pitch, a 10% measurement of ḡ can be made using some months of surface-muon beam time, and a 1% or better measurement with a correspondingly larger exposure. This could constitute the first gravitational measurement of leptonic matter, of 2nd-generation matter and, possibly, the first measurement of the gravitational acceleration of antimatter.
© Owned by the authors, published by EDP Sciences, 2015
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