Bounds on Unparticles Couplings to Electrons: from Electron g-2 to Positronium Decays

Understand

Unparticles as suggested recently by Georgi have surprising phenomenological implications, distinctive from any other new physics that we know of.

• But they must interact very feebly with ordinary matter to have avoided detection thus far.
• We determine how feebly they can interact with the electron, using the precisely measured quantities in QED: the electron g-2 and the bounds on invisible and exotic positronium decays.
• The most stringent bound comes from invisible ortho-positronium decays: the effective energy scale entering the vector unparticle-electron interaction must exceed 4 x 10^5 TeV for a scaling dimension 3/2 of the vector unparticle.