Nonlocal Portal to the Dark Sector

Abstract

We propose a nonlocal realization of the Stueckelberg portal between the Standard Model and Dark Sector, which decouple in the local limit. This implies that the mediator, $U(1)_{\rm D}$ Dark Photon $A'$ with a Stueckelberg mass, interacts nonlocally with the Standard Model quarks and leptons. We study phenomenological implications of this scenario for the meson decays into semi-invisible and invisible channels. We discuss the experimental limitations on the model parameters, including the nonlocality scale.

Figures (6)

• Figure 1: Three examples of the nonlocal form factor $\hat{\epsilon}(k^2)$ at the nonlocality scale $\Lambda_{\rm NL}=1$ TeV.
• Figure 2: Feynman diagrams contributing to $A'$ decay to lepton-antilepton pair: direct and resonance diagram.
• Figure 3: Feynman diagrams contributing to semi-invisible modes of light neutral pseudoscalars $P = \pi^0, \eta, \eta'$.
• Figure 4: Feynman diagram contributing to invisible modes of neutral vector mesons.
• Figure 5: Feynman diagrams contributing to semi-invisible decays of light pseudoscalar mesons.