Abstract
By simultaneously measuring the cyclotron frequencies of an ion and a deuteron in a coupled magnetron orbit we have made an extended series of measurements of their cyclotron frequency ratio. From the observed changes in mass energy we have followed the decay of three ions to the vibrational ground state. We are able to assign some of our measured ratios to specific rovibrational levels, hence reducing uncertainty due to rotational energy. Assuming the most probable assignment, we obtain a deuteron-to-proton mass ratio, . Combined with the atomic mass of the deuteron [S. Rau et al., Nature (London) 585, 43 (2020).] we also obtain a new value for the atomic mass of the proton, .
- Received 23 July 2021
- Accepted 9 November 2021
DOI:https://doi.org/10.1103/PhysRevLett.127.243001
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