Search for the dark photon in $B^0\to A^{\prime }{A}^{\prime }$, $A^{\prime }\to e^{+}{e}^{-}$, ${\mu }^{+}{\mu }^{-}$, and ${\pi }^{+}{\pi }^{-}$ decays at Belle

Abstract

We present a search for the dark photon $A^{\prime }$ in the $B^0\to A^{\prime }{A}^{\prime }$ decays, where $A^{\prime }$ subsequently decays to $e^{+}{e}^{-}$, ${\mu }^{+}{\mu }^{-}$, and ${\pi }^{+}{\pi }^{-}$. The search is performed by analyzing $772\times 10^6$ $B\overline{B}$ events collected by the Belle detector at the KEKB $e^{+}{e}^{-}$ energy-asymmetric collider at the ${\rm Y}(4S)$ resonance. No signal is found in the dark photon mass range $0.01\mathrm{GeV}/c^2\le m_{A^{\prime }}\le 2.62\mathrm{GeV}/c^2$, and we set upper limits of the branching fraction of $B^0\to A^{\prime }{A}^{\prime }$ at the 90\% confidence level. The products of branching fractions, $\mathcal{B}(B^0\to A^{\prime }{A}^{\prime })\times \mathcal{B}(A^{\prime }\to e^{+}{e}^{-}{)}^2$ and $\mathcal{B}(B^0\to A^{\prime }{A}^{\prime })\times \mathcal{B}(A^{\prime }\to {\mu }^{+}{\mu }^{-}{)}^2$, have limits of the order of $10^{-8}$ depending on the $A^{\prime }$ mass. Furthermore, considering $A^{\prime }$ decay rate to each pair of charged particles, the upper limits of $\mathcal{B}(B^0\to A^{\prime }{A}^{\prime })$ are of the order of $10^{-8}$-$10^{-5}$. From the upper limits of $\mathcal{B}(B^0\to A^{\prime }{A}^{\prime })$, we obtain the Higgs portal coupling for each assumed dark photon and dark Higgs mass. The Higgs portal couplings are of the order of $10^{-2}$-$10^{-1}$ at $m_{h^{\prime }}\simeq m_{B^0}\pm 40\mathrm{MeV}/c^2$ and $10^{-1}$-$1$ at $m_{h^{\prime }}\simeq m_{B^0}\pm 3\mathrm{GeV}/c^2$.

arXiv comment15 pages, 7 figures

References in corpus (20)

• Evidence for oscillation of atmospheric neutrinos
• A Unified Approach to the Classical Statistical Analysis of Small Signals
• Measurement of the rate of nu_e + d --> p + p + e^- interactions produced by 8B solar neutrinos at the Sudbury Neutrino Observatory
• Secluded U(1) below the weak scale
• TMVA - Toolkit for Multivariate Data Analysis
• Measurement of separate cosmic-ray electron and positron spectra with the Fermi Large Area Telescope
• The cosmic-ray positron energy spectrum measured by PAMELA
• Probing a Secluded U(1) at B-factories
• Including Systematic Uncertainties in Confidence Interval Construction for Poisson Statistics
• Electron Identification in Belle
• Evidence for B0->pi0pi0
• Multi-lepton Signatures of a Hidden Sector in Rare B Decays
• Muonic hydrogen and MeV forces
• New Parity-Violating Muonic Forces
• A Search for Dark Higgs Bosons
• Baryogenesis from Dark Sector
• Implications of a Light "Dark Higgs" Solution to the $g_{\mu }-2$ Discrepancy
• High-energy Cosmic-Ray Positrons from Hidden-Gauge-Boson Dark Matter
• Search for decays of neutral beauty mesons into four muons
• Lepton Flavor Violation Induced by Dark Matter

Cited by in corpus (2)

• Lepton Phenomenology of Stueckelberg Portal to Dark Sector
• 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