Electromagnetic Dipole Moments and Radiative Decays of Particles from Exchange of Fermionic Unparticles
Apr, 2008Citations per year
Abstract: (Elsevier)
We construct the propagator for a free fermionic unparticle field from basic considerations of scale and Lorentz invariance. The propagator is fixed up to a normalization factor which is required to recover the result of a free massless fermion field in the canonical limit of the scaling dimension. Two new features appear compared to the bosonic case. The propagator contains both γ and non- γ terms, and there is a relative phase of π/2 between the two in the time-like regime for arbitrary scaling dimension. This should result in additional interference effects on top of the one known in the bosonic case. The non- γ term can mediate chirality flipped transitions that are not suppressed by a light fermion mass but are enhanced by a large bosonic mass in loops, compared to the pure particle case. We employ this last feature to set stringent bounds on the Yukawa couplings between a fermionic unparticle and an ordinary fermion through electromagnetic dipole moments and radiative decays of light fermions.- 11.15.Tk
- 14.80.-j
- 13.40.Em
- 13.35.-r
- Unparticle
- Electromagnetic moment
- Radiative decay
- lepton: electric moment
- lepton: magnetic moment
- moment: dipole
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