Massless gauge bosons other than the photon

Area of Science:

• Theoretical particle physics
• High-energy physics
• Cosmology

Background:

• Standard Model fields are singlets under certain unbroken gauge symmetries.
• Gauge bosons associated with these symmetries may interact with ordinary matter via higher-dimensional operators.

Purpose of the Study:

• Present a complete set of dimension-six operators involving a massless U(1) field (gamma(')) and Standard Model fields.
• Investigate the implications of these interactions for experimental observables and cosmological phenomena.
• Explore potential connections to cold dark matter.

Main Methods:

• Construction of dimension-six operators.
• Analysis of experimental constraints from mu-->egamma(') decay, primordial nucleosynthesis, and star cooling.
• Two-loop calculations for induced gamma(') interactions with leptons and quarks.

Main Results:

• A complete set of dimension-six operators is presented.
• Lower limits in the 1-15 TeV range are established for the scale of chirality-flip operators.
• Gamma(') interactions with leptons or quarks are induced at two-loop level in simple renormalizable models.

Conclusions:

• The study provides a theoretical framework for understanding interactions of a massless U(1) gauge field with Standard Model particles.
• Experimental and cosmological data place significant constraints on new physics scales.
• These models offer a potential avenue for explaining cold dark matter in the universe.