Dark-Photon searches via Higgs-boson production at the LHC

Understand

Dark photons $\bar \gamma$ mediating long-range forces in a dark sector are predicted by various new physics scenarios, and are being intensively searched for in experiments.

• We extend a previous study of a new discovery process for dark photons proceedings via Higgs-boson production at the LHC.
• Thanks to the non-decoupling properties of the Higgs boson, BR($H\to \gamma\bar \gamma$) values up to a few percent are possible for a massless dark photon, even for heavy dark-sector scenarios.
• The corresponding signature consists (for a Higgs boson at rest) of a striking monochromatic photon with energy $E_{\gamma}= m_H/2$, and similar amount of missing energy.