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arXiv · hep-ph/9908439

Muonium Decay

Andrzej Czarnecki·G. Peter Lepage·William J. Marciano
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Abstract

Modifications of the mu+ lifetime in matter due to muonium (M = mu+ e-) formation and other medium effects are examined. Muonium and free mu+ decay spectra are found to differ at O(alpha m_e/m_mu) from Doppler broadening and O(alpha^2 m_e/m_mu) from the Coulomb bound state potential. However, both types of corrections are shown to cancel in the total decay rate due to Lorentz and gauge invariance respectively, leaving a very small time dilation lifetime difference, (tau_M - tau_mu+)/tau_mu+ = alpha^2 m_e^2/ 2m_mu^2 \simeq 6\times 10^-10, as the dominant bound state effect. It is argued that other medium effects on the stopped mu+ lifetime are similarly suppressed.

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Andrzej Czarnecki, G. Peter Lepage, William J. Marciano. 1999-09-27. Muonium Decay. https://doi.org/10.1103/physrevd.61.073001

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