Search for C -parity violation in J/ψ→γγ and γϕ

Le résumé fourni par la source

Using $1.06\ifmmode\times\else\texttimes\fi{}1{0}^{8}$ $\ensuremath{\psi}(3686)$ events recorded in ${e}^{+}{e}^{\ensuremath{-}}$ collisions at $\sqrt{s}=3.686\text{ }\mathrm{GeV}$ with the BESIII at the BEPCII collider, we present searches for $C$-parity violation in $J/\ensuremath{\psi}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma}$ and $\ensuremath{\gamma}\ensuremath{\phi}$ decays via $\ensuremath{\psi}(3686)\ensuremath{\rightarrow}J/\ensuremath{\psi}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$. No significant signals are observed in either channel. Upper limits on the branching fractions are set to be $\mathcal{B}(J/\ensuremath{\psi}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma})<2.7\ifmmode\times\else\texttimes\fi{}1{0}^{\ensuremath{-}7}$ and $\mathcal{B}(J/\ensuremath{\psi}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\phi})<1.4\ifmmode\times\else\texttimes\fi{}1{0}^{\ensuremath{-}6}$ at the 90% confidence level. The former is one order of magnitude more stringent than the previous upper limit, and the latter represents the first limit on this decay channel.

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