Massless Gauge Bosons other than the Photon

TL;DR

The mu-->egamma(') decay, primordial nucleosynthesis, star cooling, and other phenomena set lower limits on the scale of chirality-flip operators in the 1-15 TeV range if the operators have coefficients given by the corresponding Yukawa couplings.

Abstract

Gauge bosons associated with unbroken gauge symmetries, under which all standard model fields are singlets, may interact with ordinary matter via higher-dimensional operators. A complete set of dimension-six operators involving a massless U(1) field, gamma-prime, and standard model fields is presented. The mu to e gamma-prime decay, primordial nucleosynthesis, star cooling and other phenomena set lower limits on the scale of chirality-flip operators in the 1 - 15 TeV range, if the operators have coefficients given by the corresponding Yukawa couplings. Simple renormalizable models induce gamma-prime interactions with leptons or quarks at two loops, and may provide a cold dark matter candidate.

Figures (2)

• Figure 1: Paraphoton annihilation via muon pair production ($\gamma^\prime\gamma \rightarrow \mu^+\mu^-$) and Compton-like processes ($\gamma^\prime\mu^\pm \rightarrow \gamma\mu^\pm$).
• Figure 2: Electron-paraphoton interaction induced in a renormalizable model.