“Dark” Z implications for parity violation, rare meson decays, and Higgs physics

• Published in: Physical review. D, Particles, fields, gravitation, and cosmology Particles, fields, gravitation, and cosmology, 2012-06, Vol.85 (11), Article 115019
• Main Authors: Davoudiasl, Hooman, Lee, Hye-Sung, Marciano, William J.
• Format: Article
• Language: English
• Subjects: 72; Bosons; Channels; Decay; Large Hadron Collider; Mesons; Parity; Searching; Texts
• ISSN: 1550-7998; 1550-2368
• DOI: 10.1103/PhysRevD.85.115019

General consequences of mass mixing between the ordinary Z boson and a relatively light Z sub(d) boson, the "dark" Z, arising from a U(1) sub(d) gauge symmetry, associated with a hidden sector such as dark matter, are examined. New effects beyond kinetic mixing are emphasized. Z-Z sub(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 super(+)l super(-) (l =e, mu ) and [pi](K)vv are found to already place tight constraints on the size of Z-Z sub(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 sub(d) mixing can also lead to the Higgs decay H arrow right ZZ sub(d), followed by Z arrow right l(ProQuest: Formulae and/or non-USASCII text omitted)l(ProQuest: Formulae and/or non-USASCII text omitted) and Z sub(d) arrow right l(ProQuest: Formulae and/or non-USASCII text omitted)l(ProQuest: Formulae and/or non-USASCII text omitted) or "missing energy," providing a potential hidden sector discovery channel at the Large Hadron Collider. An illustrative realization of these effects in a 2 Higgs doublet model is presented.