"Dark" Z implications for Parity Violation, Rare Meson Decays, and Higgs Physics
Abstract
General consequences of mass mixing between the ordinary Z boson and a relatively light Z_d boson, the "dark" Z, arising from a U(1)_d gauge symmetry, associated with a hidden sector such as dark matter, are examined. New effects beyond kinetic mixing are emphasized. Z-Z_d mixing introduces a new source of low energy parity violation well explored by possible future atomic parity violation and planned polarized electron scattering experiments. Rare K (B) meson decays into pi (K) l^+ l^- (l = e, mu) and pi (K) nu anti-nu are found to already place tight constraints on the size of Z-Z_d mixing. Those sensitivities can be further improved with future dedicated searches at K and B factories as well as binned studies of existing data. Z-Z_d mixing can also lead to the Higgs decay H -> Z Z_d, followed by Z -> l_1^+ l_1^- and Z_d -> l_2^+ l_2^- or "missing energy", providing a potential hidden sector discovery channel at the LHC. An illustrative realization of these effects in a 2 Higgs doublet model is presented.
Cite
@article{arxiv.1203.2947,
title = {"Dark" Z implications for Parity Violation, Rare Meson Decays, and Higgs Physics},
author = {Hooman Davoudiasl and Hye-Sung Lee and William J. Marciano},
journal= {arXiv preprint arXiv:1203.2947},
year = {2013}
}
Comments
Version to appear in PRD