Observation of the doubly radiative decay ${\eta }^{\prime }\to \gamma \gamma {\pi }^0$

Abstract

Based on a sample of $1.31$ billion $J/\psi$ events collected with the BESIII detector, we report the study of the doubly radiative decay ${\eta }^{\prime }\to \gamma \gamma {\pi }^0$ for the first time, where the ${\eta }^{\prime }$ meson is produced via the $J/\psi \to \gamma {\eta }^{\prime }$ decay. The branching fraction of ${\eta }^{\prime }\to \gamma \gamma {\pi }^0$ inclusive decay is measured to be $\mathcal{B}({\eta }^{\prime }\to \gamma \gamma {\pi }^0{)}_{\text{Incl.}}$ = $(3.20\pm0.07\mbox{(stat)}\pm0.23\mbox{(sys)})\times 10^{-3}$, while the branching fractions of the dominant process ${\eta }^{\prime }\to \gamma \omega$ and the non-resonant component are determined to be ${\cal B}(η^\prime\to γω)\times {\cal B}(ω\to γπ^0) = (23.7 \pm1.4\mbox{(stat)}\pm1.8\mbox{(sys)})\times 10^{-4}$ and ${\cal B}(η^\prime\to γγπ^0)_{\text{NR}} = (6.16\pm0.64\mbox{(stat)} \pm0.67\mbox{(sys)})\times 10^{-4}$, respectively. In addition, the $M_{\gamma \gamma }^2$-dependent partial widths of the inclusive decay are also presented.

References in corpus (8)

• Design and Construction of the BESIII Detector
• The Precision Monte Carlo Event Generator KK For Two-Fermion Final States In e+e- Collisions
• Coherent Exclusive Exponentiation For Precision Monte Carlo Calculations
• Precision Measurement of the e+e- --> K+K-(gamma) Cross Section with the Initial-State Radiation Method at BaBar
• Isospin Violation in Chiral Perturbation Theory and the Decays $η\ra π\ell ν$ and $τ\ra ηπν$
• Determination of the number of $J/\psi$ events with inclusive $J/\psi$ decays
• Measurement of the Matrix Element for the Decay ${\eta }^{\prime }\to \eta {\pi }^{+}{\pi }^{-}$
• $\eta$ and ${\eta }^{\prime }$ Physics at BES-III

Cited by in corpus (9)

• Neutron Stars with Baryon Number Violation, Probing Dark Sectors
• Numerical calculation of the decay widths, the decay constants, and the decay energy spectra of the resonances of the delta-shell potential
• A theoretical analysis of the doubly radiative decays ${\eta }^{(\prime )}\to {\pi }^0\gamma \gamma$ and ${\eta }^{\prime }\to \eta \gamma \gamma$
• An overview of $\eta$ and ${\eta }^{\prime }$ decays at BESIII
• The semileptonic decays ${\eta }^{(\prime )}\to {\pi }^0{\ell }^{+}{\ell }^{-}$ and ${\eta }^{\prime }\to \eta {\ell }^{+}{\ell }^{-}$ in the standard model
• Search for the decay ${\eta }^{\prime }\to \gamma \gamma \eta$
• Neutron star structure with a new force between quarks
• Sensitivity of the ${\eta }^{(\prime )}\to {\pi }^0\gamma \gamma$ and ${\eta }^{\prime }\to \eta \gamma \gamma$ decays to a sub-GeV leptophobic $U(1{)}_B$ boson
• Amplitude Analysis of the Isospin-Violating Decay $J/\psi \to \gamma \eta {\pi }^0$