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arXiv · hep-ph/0703140

The Lamb shift contribution of very light millicharged particles

M. Gluck·S. Rakshit·E. Reya
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Abstract

The leading order vacuum polarization contribution of very light millicharged fermions and scalar (spin-0) particles with charge εe and mass μto the Lamb shift of the hydrogen atom is shown to imply universal, i.e. μ-independent, upper bounds on ε: ε\lsim 10^{-4} for μ\lsim 1 keV in the case of fermions, and for scalars this bound is increased by a factor of 2. This is in contrast to expectations based on the commonly used approximation to the Uehling potential relevant only for conventionally large fermion (and scalar) masses.

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M. Gluck, S. Rakshit, E. Reya. 2007-09-03. The Lamb shift contribution of very light millicharged particles. https://doi.org/10.1103/physrevd.76.091701

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