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MULTIPOLE AMPLITUDES IN $\psi (2S)$ $\to$ $\gamma {\chi }_{c1}(1S)$ RADIATIVE DECAY

${\mathit{b}}_2$ = $\mathit{M}2/\sqrt{\mathit{E}1{}^2+\mathit{M}2{}^2}$ Magnetic quadrupole fractional transition amplitude

INSPIRE   PDGID:

M055QB2

VALUE (${10}^{-2}$) EVTS DOCUMENT ID TECN  COMMENT $\mathbf{2.5}\pm \mathbf{0.4}$ OUR AVERAGE $2.29$ $\pm 0.39$ $\pm 0.27$ 164k 1 ABLIKIM 2017 N BES3 $\psi (2S)$ $\to$ $\gamma \gamma {\ell }^{+}{\ell }^{-}$ $2.76$ $\pm 0.73$ $\pm 0.23$ 39k ARTUSO 2009 CLEO $\psi (2S)$ $\to$ $\gamma \gamma {\ell }^{+}{\ell }^{-}$ $7.7$ ${}_{-4.5}^{+5.0}$ 921 OREGLIA 1982 CBAL $\psi (2S)$ $\to$ $\gamma \gamma {\ell }^{+}{\ell }^{-}$ 1  Correlated with ${\mathit{a}}_2$ with correlation coefficient ${\rho }_{{\mathit{a}}_2{\mathit{b}}_2}$ = 0.133.

References

ABLIKIM 2017N PR D95 072004 Measurement of Higher-Order Multipole Amplitudes in $\psi (3686)$ $\to$ $\gamma {\chi }_{c1,2}$ with ${\chi }_{c1,2}$ $\to$ $\gamma \mathit{J}/\psi$ and Search for the Transition ${\eta }_c(2S)$ $\to$ $\gamma \mathit{J}/\psi$ ARTUSO 2009 PR D80 112003 Higher-Order Multipole Amplitudes in Charmonium Radiative Transitions OREGLIA 1982 PR D25 2259 Study of the Reaction ${\psi }^{{}^{\prime }}$ $\to$ $\gamma \gamma \mathit{J}/\psi$ Also Private Comm. Private Communication

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