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MULTIPOLE AMPLITUDES IN ${{\mathit \chi}_{{c2}}{(1P)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit J / \psi}{(1S)}}$ RADIATIVE DECAY

$\mathit a_{2}$ = $\mathit M2/\sqrt {\mathit E1{}^{2}+\mathit M2{}^{2}+\mathit E3{}^{2} }$ Magnetic quadrupole fractional transition amplitude

INSPIRE   PDGID:

M057A1

VALUE ($ 10^{-2} $) EVTS DOCUMENT ID TECN  COMMENT $\bf{ -11.0 \pm1.0}$ OUR AVERAGE $-12.0$ $\pm1.3$ $\pm0.4$ 89k 1 ABLIKIM 2017 N BES3 ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}{{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$ $-9.3$ $\pm1.6$ $\pm0.3$ 19.8k 2 ARTUSO 2009 CLEO ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}{{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$ $-9.3$ ${}^{+3.9}_{-4.1}$ $\pm0.6$ 5.9k 3 AMBROGIANI 2002 E835 ${{\mathit p}}$ ${{\overline{\mathit p}}}$ $\rightarrow$ ${{\mathit \chi}_{{c2}}}$ $\rightarrow$ ${{\mathit J / \psi}}{{\mathit \gamma}}$ $-14$ $\pm6$ 1.9k 3 ARMSTRONG 1993 E E760 ${{\mathit p}}$ ${{\overline{\mathit p}}}$ $\rightarrow$ ${{\mathit \chi}_{{c2}}}$ $\rightarrow$ ${{\mathit J / \psi}}{{\mathit \gamma}}$ $-33.3$ ${}^{+11.6}_{-29.2}$ 441 3 OREGLIA 1982 CBAL ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \chi}_{{c1}}}{{\mathit \gamma}}$ $\rightarrow$ ${{\mathit J / \psi}}{{\mathit \gamma}}{{\mathit \gamma}}$ • • We do not use the following data for averages, fits, limits, etc. • • $-7.9$ $\pm1.9$ $\pm0.3$ 19.8k 4 ARTUSO 2009 CLEO ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}{{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$ 1  Correlated with ${{\mathit a}_{{3}}}$, ${{\mathit b}_{{2}}}$, and ${{\mathit b}_{{3}}}$ with correlation coefficients $\rho _{ {{\mathit a}_{{2}}} {{\mathit a}_{{3}}} }$ = $0.733$, $\rho _{ {{\mathit a}_{{2}}} {{\mathit b}_{{2}}} }$ = $-0.605$, and $\rho _{ {{\mathit a}_{{2}}} {{\mathit b}_{{3}}} }$ = $-0.095$. 2  From a fit with floating $\mathit M2$ amplitudes $\mathit a_{2}$ and $\mathit b_{2}$, and fixed $\mathit E3$ amplitudes $\mathit a_{3}=\mathit b_{3}$=0. 3  Assuming $\mathit a_{3}$=0. 4  From a fit with floating $\mathit M2$ and $\mathit E3$ amplitudes $\mathit a_{2}$, $\mathit b_{2}$, and $\mathit a_{3}$, and $\mathit b_{3}$.

References:

ABLIKIM 2017N PR D95 072004 Measurement of Higher-Order Multipole Amplitudes in ${{\mathit \psi}{(3686)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \chi}_{{c1,2}}}$ with ${{\mathit \chi}_{{c1,2}}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit J / \psi}}$ and Search for the Transition ${{\mathit \eta}_{{c}}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit J / \psi}}$ ARTUSO 2009 PR D80 112003 Higher-Order Multipole Amplitudes in Charmonium Radiative Transitions AMBROGIANI 2002 PR D65 052002 Study of the Angular Distributions of the Reactions ${{\overline{\mathit p}}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \chi}_{{c1}}}$ , ${{\mathit \chi}_{{c2}}}$ $\rightarrow$ ${{\mathit J / \psi}}{{\mathit \gamma}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}{{\mathit \gamma}}$ ARMSTRONG 1993E PR D48 3037 Study of the Angular Distribution of the Reaction ${{\overline{\mathit p}}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \chi}_{{c2}}}$ $\rightarrow$ ${{\mathit J / \psi}}{{\mathit \gamma}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit e}^{-}}{{\mathit \gamma}}$ OREGLIA 1982 PR D25 2259 Study of the Reaction ${{\mathit \psi}^{\,'}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}{{\mathit J / \psi}}$ Also Private Comm. Private Communication

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