Search for the dark photon and the dark Higgs boson at Belle

Abstract

The dark photon, $A^{\prime }$, and the dark Higgs boson, $h^{\prime }$, are hypothetical constituents featured in a number of recently proposed Dark Sector Models. Assuming prompt decays of both dark particles, we search for their production in the so-called Higgs-strahlung channel, $e^{+}{e}^{-}\to A^{\prime }{h}^{\prime }$, with $h^{\prime }\to A^{\prime }{A}^{\prime }$. We investigate ten exclusive final-states with $A^{\prime }\to e^{+}{e}^{-}$, ${\mu }^{+}{\mu }^{-}$, or ${\pi }^{+}{\pi }^{-}$, in the mass ranges $0.1$~GeV/$c^2$~$<m_{A^{\prime }}<3.5$~GeV/$c^2$ and $0.2$~GeV/$c^2$~$<m_{h^{\prime }}<10.5$~GeV/$c^2$. We also investigate three inclusive final-states, $2(e^{+}{e}^{-})X$, $2({\mu }^{+}{\mu }^{-})X$, and $(e^{+}{e}^{-})({\mu }^{+}{\mu }^{-})X$, where $X$ denotes a dark photon candidate detected via missing mass, in the mass ranges $1.1$~GeV/$c^2$~$<m_{A^{\prime }}<3.5$~GeV/$c^2$ and $2.2$~GeV/$c^2$~$<m_{h^{\prime }}<10.5$~GeV/$c^2$. Using the entire $977{\mathrm{fb}}^{-1}$ data set collected by Belle, we observe no significant signal. We obtain individual and combined 90$\%$ confidence level upper limits on the branching fraction times the Born cross section, $\mathcal{B}\times {\sigma }_{\mathrm{Born}}$, on the Born cross section, ${\sigma }_{\mathrm{Born}}$, and on the dark photon coupling to the dark Higgs boson times the kinetic mixing between the Standard Model photon and the dark photon, ${\alpha }_D\times {\epsilon }^2$. These limits improve upon and cover wider mass ranges than previous experiments. The limits from the final-states $3({\pi }^{+}{\pi }^{-})$ and $2(e^{+}{e}^{-})X$ are the first placed by any experiment. For ${\alpha }_D$ equal to 1/137, $m_{h^{\prime }}<$ 8 GeV/$c^2$, and $m_{A^{\prime }}<$ 1 GeV/$c^2$, we exclude values of the mixing parameter, $\epsilon$, above $\sim 8\times 10^{-4}$.

References in corpus (17)

• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• Observation of an anomalous positron abundance in the cosmic radiation
• A Theory of Dark Matter
• Secluded WIMP Dark Matter
• First results from DAMA/LIBRA and the combined results with DAMA/NaI
• Results from a Search for Light-Mass Dark Matter with a P-type Point Contact Germanium Detector
• Search for a dark photon in e+e- collisions at BABAR
• First Dark Matter Results from the XENON100 Experiment
• Non-Abelian Dark Sectors and Their Collider Signatures
• Probing a Secluded U(1) at B-factories
• Probing Dark Forces and Light Hidden Sectors at Low-Energy e+e- Colliders
• Search for light massive gauge bosons as an explanation of the $(g-2{)}_{\mu }$ anomaly at MAMI
• Kinetic Mixing as the Origin of Light Dark Scales
• Discovering New Light States at Neutrino Experiments
• Breaking the Dark Force
• Dark matter and sub-GeV hidden U(1) in GMSB models
• Detecting light leptophilic gauge boson at BESIII detector

Cited by in corpus (17)

• Dark Higgs Bosons at Colliders
• Flavor Physics and CP Violation
• Dark Photons from Nuclear Transitions
• Search for a dark photon and an invisible dark Higgs boson in ${\mu }^{+}{\mu }^{-}$ and missing energy final states with the Belle II experiment
• Rare $Z$ Boson Decays to a Hidden Sector
• Search for a dark vector gauge boson decaying to ${\pi }^{+}{\pi }^{-}$ using $\eta \to {\pi }^{+}{\pi }^{-}\gamma$ decays
• Dark Sector first results at Belle II
• Searching for dark sectors in multi lepton final state in e+ e- collisions
• Search for light long-lived neutral particles from Higgs boson decays via vector-boson-fusion production from $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
• Multi-frequency test of dark matter annihilation into long-lived particles in Sirius
• Searches for Light Scalars, Pseudoscalars, and Gauge Bosons
• Search for light neutral particles decaying promptly into collimated pairs of electrons or muons in $pp$ collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector
• Multi-track Displaced Vertices at B-Factories
• Search for Dark Photons in Rare $Z$ Boson Decays with the ATLAS Detector
• Dark sector searches with high-intensity positron beams in the CERN North Area
• Higgs Boson Searches at the LHC Beyond the Standard Model
• The Dark Photon: a 2026 Perspective