2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/197347Gauge 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.5 pagesHigh Energy Physics - PhenomenologyAstrophysicstext