Measurement of B(J/ψ→η′e+e−) and search for a dark photon

Citations Over TimeTop 10% of 2019 papers

Abstract

Using a data sample of $(1310.6\ifmmode\pm\else\textpm\fi{}7.0)\ifmmode\times\else\texttimes\fi{}{10}^{6}\text{ }\text{ }J/\ensuremath{\psi}$ decay events collected with the BESIII detector at BEPCII, we study the electromagnetic Dalitz decay $J/\ensuremath{\psi}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{e}^{+}{e}^{\ensuremath{-}}$ with two dominant ${\ensuremath{\eta}}^{\ensuremath{'}}$ decay modes, ${\ensuremath{\eta}}^{\ensuremath{'}}\ensuremath{\rightarrow}\ensuremath{\gamma}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ and ${\ensuremath{\eta}}^{\ensuremath{'}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{\eta}$. The branching fraction is determined to be $\mathcal{B}(J/\ensuremath{\psi}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{e}^{+}{e}^{\ensuremath{-}})=\phantom{\rule{0ex}{0ex}}(6.59\ifmmode\pm\else\textpm\fi{}0.07\ifmmode\pm\else\textpm\fi{}0.17)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$, which improves in precision by a factor of 2 over the previous BESIII measurement. A search for the dark photon (${\ensuremath{\gamma}}^{\ensuremath{'}}$) is performed via $J/\ensuremath{\psi}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{\ensuremath{\gamma}}^{\ensuremath{'}}$, ${\ensuremath{\gamma}}^{\ensuremath{'}}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}$. Excluding the $\ensuremath{\omega}$ and $\ensuremath{\phi}$ mass regions, no significant signal is observed in the mass range from 0.1 to $2.1\text{ }\text{ }\mathrm{GeV}/{c}^{2}$. We set upper limits at the 90% confidence level on $\mathcal{B}(J/\ensuremath{\psi}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{\ensuremath{\gamma}}^{\ensuremath{'}})\ifmmode\times\else\texttimes\fi{}\mathcal{B}({\ensuremath{\gamma}}^{\ensuremath{'}}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}})$, $\mathcal{B}(J/\ensuremath{\psi}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{\ensuremath{\gamma}}^{\ensuremath{'}}$) and the mixing strength as a function of dark photon mass. This is among the first searches for dark photons in charmonium decays.

Related Papers

• → Remarks on Algorithm 2, Algorithm 3, Algorithm 15, Algorithm 25 and Algorithm 26(1961)2 cited
• → Remarks on Algorithm 332: Jacobi polynomials: Algorithm 344: student's t -distribution: Algorithm 351: modified Romberg quadrature: Algorithm 359: factoral analysis of variance(1970)
• Using DataGrid Control to Realize DataBase of Querying in VB6.0(2000)
• Susquehanna Chorale Spring Concert "Roots and Wings"(2017)
• → ИСПОЛЬЗОВAНИЕ ПОТЕНЦИAЛA СОЦИAЛЬНЫХ ПAРТНЕРОВ В ПОДГОТОВКЕ БУДУЩИХ ПЕДAГОГОВ(2024)