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arXiv · 1605.03300

Measurement of the charged pion mass using X-ray spectroscopy of exotic atoms

M Trassinelli·D. F. Anagnostopoulos·G. Borchert·A. Dax·J. P Egger·D. Gotta·M. Hennebach·P. Indelicato·Y. -W. Liu·B. Manil·N. Nelms·L. M. Simons·A. Wells
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Abstract

The $5g-4f$ transitions in pionic nitrogen and muonic oxygen were measured simultaneously by using a gaseous nitrogen-oxygen mixture at 1.4\,bar. Due to the precise knowledge of the muon mass the muonic line provides the energy calibration for the pionic transition. A value of (139.57077\,$\pm$\,0.00018)\,MeV/c$^{2}$ ($\pm$\,1.3ppm) is derived for the mass of the negatively charged pion, which is 4.2ppm larger than the present world average.

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M Trassinelli, D. F. Anagnostopoulos, G. Borchert, A. Dax, J. P Egger, D. Gotta, M. Hennebach, P. Indelicato, Y. -W. Liu, B. Manil, N. Nelms, L. M. Simons, A. Wells. 2016-05-11. Measurement of the charged pion mass using X-ray spectroscopy of exotic atoms. https://doi.org/10.1016/j.physletb.2016.06.025

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