Study of the Magnetic Dipole Transition of $J/\psi \to \gamma {\eta }_c$ via ${\eta }_c\to p\bar{p}$

Abstract

Using $(10.087\pm 0.044)\times 10^9$ $J/\psi$ events collected with the BESIII detector at the $e^{+}{e}^{-}$ BEPCII collider, we present the first amplitude analysis of $J/\psi \to \gamma p\bar{p}$ with the $p\bar{p}$ invariant mass in the ${\eta }_c$ mass region $[2.70,3.05]$~GeV/$c^2$. The product branching fraction $\mathcal{B}(J/\psi \to \gamma {\eta }_c)\times \mathcal{B}({\eta }_c\to p\bar{p})$ is precisely determined to be $(2.11\pm 0.02_{\mathrm{stat}}\pm 0.07_{\mathrm{syst}})\times 10^{-5}$. Combining with the product branching fractions $\mathcal{B}({\eta }_c\to p\bar{p})\times \mathcal{B}({\eta }_c\to \gamma \gamma )$ and $\mathcal{B}(J/\psi \to \gamma {\eta }_c)\times \mathcal{B}({\eta }_c\to \gamma \gamma )$, the branching fractions of $\mathcal{B}(J/\psi \to \gamma {\eta }_c)$ and $\mathcal{B}({\eta }_c\to \gamma \gamma )$ are calculated to be $(2.29\pm 0.01_{\mathrm{stat}}\pm 0.04_{\mathrm{syst}}\pm 0.18_{\mathrm{opbf}})\%$ and $(2.28\pm 0.01_{\mathrm{stat}}\pm 0.04_{\mathrm{syst}}\pm 0.18_{\mathrm{opbf}})\times 10^{-4}$, respectively, which are consistent with the latest lattice quantum chromodynamics calculations. Here, opbf is the uncertainty from the other product branching fractions used in the calculation.

arXiv comment11 Pages, 3 figures, submit to PRL

References in corpus (46)

• 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
• Higher Charmonia
• Future Physics Programme of BESIII
• Highly Improved Staggered Quarks on the Lattice, with Applications to Charm Physics
• Properties of heavy quarkonia and B_c mesons in the relativistic quark model
• Search for hadronic transition ${\chi }_{cJ}\to {\eta }_c{\pi }^{+}{\pi }^{-}$ and observation of ${\chi }_{cJ}\to K\bar{K}\pi \pi \pi$
• Radiative Transitions in Charmonium from Lattice QCD
• Precision tests of the J/ψ from full lattice QCD: mass, leptonic width and radiative decay rate to η_c
• Study of ${\chi }_{cJ}$ radiative decays into a vector meson
• Charmonium spectrum and their electromagnetic transitions with higher multipole contributions
• Number of $J/\psi$ events at BESIII
• Exotic and excited-state radiative transitions in charmonium from lattice QCD
• Model-independent Study of Magnetic Dipole Transitions in Quarkonium
• J/psi and psi(2S) Radiative Transitions to eta_c
• Quarkonium mass splittings in three-flavor lattice QCD
• Two Photon Decays of Charmonia from Lattice QCD
• Lattice QCD study of the radiative decays $J/\psi \to {\eta }_c\gamma$ and $h_c\to {\eta }_c\gamma$
• Charmonium properties from lattice QCD + QED: hyperfine splitting, $J/\psi$ leptonic width, charm quark mass and $a_{\mu }^c$
• Charmonium potential from full lattice QCD
• Improved determination of Heavy Quarkonium magnetic dipole transitions in pNRQCD
• Radiative transitions in charmonium from $N_f=2$ twisted mass lattice QCD
• Study of the pseudoscalar glueball in $J/\psi$ radiative decays
• Measurement of gamma gamma -> p p-bar production at Belle
• Next-to-next-to-leading-order QCD corrections to hadronic width of pseudoscalar quarkonium
• Partial wave analysis of J/psi to p pbar pi0
• Two Photon Transition Form Factor of $\bar{c}c$ Quarkonia
• Measurement of $J/\psi \to \gamma {\eta }_{\mathrm{c}}$ decay rate and ${\eta }_{\mathrm{c}}$ parameters at KEDR
• Precise determination of decay rates for ${\eta }_c\to \gamma \gamma$, $J/\psi \to \gamma {\eta }_c$ and $J/\psi \to {\eta }_c{e}^{+}{e}^{-}$ from lattice QCD
• Two Photon Decays of ${\eta }_c$ from Lattice QCD
• Covariant tensor formalism for partial wave analyses of $\psi$ decays into $\gamma B\bar{B}$, $\gamma \gamma V$ and $\psi (2S)\to \gamma {\chi }_{c0,1,2}$ with ${\chi }_{c0,1,2}\to K\bar{K}{\pi }^{+}{\pi }^{-}$ and $2{\pi }^{+}2{\pi }^{-}$
• First-principle calculation of ${\eta }_c\to 2\gamma$ decay width from lattice QCD
• Resummation of QCD Corrections to the eta_c Decay Rate
• Measurement of J/psi to eta_c gamma at KEDR
• Inclusive decays of ${\eta }_c$ and ${\eta }_b$ at NNLO with large $n_f$ resummation
• The heavy quarkonium inclusive decays using the principle of maximum conformality
• Ward Identity of the Vector Current and the Decay Rate of ${\eta }_c\to \gamma \gamma$ in Lattice QCD
• A Lattice Study of the Two-photon Decay Widths for Scalar and Pseudo-scalar Charmonium
• Observation of ${\eta }_c\to \omega \omega$ in $J/\psi \to \gamma \omega \omega$
• Study of the radiative decay $J/\psi \to {\eta }_c+\gamma$ in light cone sum rules
• Observation of ${\eta }_c$ decay into ${\Sigma }^{+}{\bar{\Sigma }}^{-}$ and ${\Xi }^{-}{\bar{\Xi }}^{+}$ final states
• Observation of the charmonium decay ${\eta }_c\to \gamma \gamma$ in $J/\psi \to \gamma {\eta }_c$
• Improved measurements of branching fractions for ${\eta }_c\to \varphi \varphi$ and $\omega \varphi$
• Lattice study of $J/\psi \to \gamma {\eta }_c$ using a method without momentum extrapolation
• Line shape and the experimental determination of the $J/\psi \to \gamma {\eta }_c$ branching fraction