Dirac dark matter and $b \to s \ell^+ \ell^-$ with $\mathrm{U(1)}$ gauge symmetry

TL;DR

This paper explores a minimal U(1) gauge symmetry extension of the Standard Model that links Dirac dark matter to b to s l+ l- anomalies, identifying viable parameter space consistent with current experimental constraints.

Contribution

It introduces a U(1)' gauge symmetry model with a Z' portal that explains flavor anomalies and dark matter stability, providing a unified framework for these phenomena.

Findings

Viable parameter space with TeV-scale dark matter and Z' masses.

Model consistent with flavor, collider, and dark matter detection constraints.

Explains b to s l+ l- anomalies while accounting for dark matter relic abundance.

Abstract

We revisit the possibility of a Dirac fermion dark matter candidate in the light of current $b \to s \ell^+ \ell^-$ anomalies by investigating a minimal extension of the Standard Model with a horizontal $\mathrm{U(1)}^{\prime}$ local symmetry. Dark matter stability is protected by a remnant $\mathcal{Z}_2$ symmetry arising after spontaneous symmetry breaking of $\mathrm{U(1)}^{\prime}$. The associated $Z^{\prime}$ gauge boson can accommodate current hints of new physics in $b \to s \ell^+ \ell^-$ decays, and acts as a vector portal between dark matter and the visible sector. We find that the model is severely constrained by a combination of precision measurements at flavour factories, LHC searches for dilepton resonances, as well as direct and indirect dark matter searches. Despite this, viable regions of the parameter space accommodating the observed dark matter relic abundance and the $b \to s \ell^+ \ell^-$ anomalies still persist for dark matter and $Z^{\prime}$ masses in the TeV range.