We show that the electromagnetic moments of unstable particles (resonances) have an absorptive contribution which quantifies the change of the particle's lifetime in an external electromagnetic field. To give an example we compute here the imaginary part of the magnetic moment for the cases of the muon and the neutron at leading order in the electroweak coupling. We also consider an analogous effect for the strongly decaying (1232) resonance. The result for the muon is Im μ = eG2Fm3/768π3, with e being the charge and m the mass of the muon, GF the Fermi constant, which in an external magnetic field of B Tesla give rise to the relative change in the muon lifetime of 3 × 10−15B. For the neutron the effect is of a similar magnitude. We speculate on the observable implications of this effect.

The lifetime of unstable particles in electromagnetic fields

Binosi, Daniele;Pascalutsa, Vladimir
2009

Abstract

We show that the electromagnetic moments of unstable particles (resonances) have an absorptive contribution which quantifies the change of the particle's lifetime in an external electromagnetic field. To give an example we compute here the imaginary part of the magnetic moment for the cases of the muon and the neutron at leading order in the electroweak coupling. We also consider an analogous effect for the strongly decaying (1232) resonance. The result for the muon is Im μ = eG2Fm3/768π3, with e being the charge and m the mass of the muon, GF the Fermi constant, which in an external magnetic field of B Tesla give rise to the relative change in the muon lifetime of 3 × 10−15B. For the neutron the effect is of a similar magnitude. We speculate on the observable implications of this effect.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11582/330402
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