'Dark' Z implications for Parity Violation, Rare Meson Decays, and Higgs Physics

By H. Davoudiasl, Hye-Sung Lee, W. Marciano. 2012

226 citations recorded by the source corpus.

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.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/a973bde2da6c07711a6ad6c37f5435cea98a9f9c

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In Nuclear and High Energy Physics

1. M. Drewes
2. M. Shaposhnikov
3. R. Essig
4. A. Ringwald
5. K. Zurek
6. Alexey Boyarsky
7. Oleg Ruchayskiy
8. J. Redondo

Citations in the corpus

• Particle physics models for the 17 MeV anomaly in beryllium nuclear decays (2016, background): “[139] H.”
• Neutrino Oscillations and Non-standard Interactions (2017, background): “Moreover, the VEV of H ′ can induce Z − Z ′ mixing on which there are strong bounds [191].”
• Illuminating dark photons with high-energy colliders (2014, background): “1 There are many experimental probes of dark photons with a mass above 1 MeV that decay directly to SM particles, including precision QED measurements, rare meson decays, supernova cooling, collider experiments, and beam dumps [31–66].”
• Search for New Physics with Atoms and Molecules (2017, background): “Indeed, some of the best constraints on interactions mediated by new spin-1 (Z ′) bosons have been derived from atomic parity violation experiments Bouchiat and Fayet (2005); Davoudiasl et al. (2012); Dzuba et al. (2017).”
• A facility to search for hidden particles at the CERN SPS: the SHiP physics case (2015, background): “In particular, a mass mixing between V and the SM Z boson becomes possible [87], opening a host of additional phenomenological consequences such as parity violation mediated by V exchange and the coupling of V to the SM neutrinos.”
• The P2 experiment (2018, background): “Low-Q(2) measurements also have unique sensitivity to certain beyond the Standard Model scenarios such as those involving so-called dark Z bosons [139], which are light (on the order of tens of MeV) and very weakly coupled extra neutral gauge bosons which may mix with the ordinary Z boson, and which”
• The Dark Photon (2020, background): “(1) but the mass term between the dark photon and the Zboson is taken non-diagonal and therefore giving a mixing between these two states (Appelquist et al., 2003; Babu et al., 1998; Davoudiasl et al., 2012; Galison and Manohar, 1984; He et al., 1991).”