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MULTIPOLE AMPLITUDES IN ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \chi}_{{c2}}{(1P)}}$ RADIATIVE DECAY

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

INSPIRE   PDGID:

M057QB2

VALUE ($ 10^{-2} $) EVTS DOCUMENT ID TECN  COMMENT $\bf{ 1.9 \pm0.9}$ OUR AVERAGE  Error includes scale factor of 1.4.  See the ideogram below. $1.7$ $\pm0.8$ $\pm0.2$ 89k 1 ABLIKIM 2017 N BES3 ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}{{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$ $4.6$ $\pm1.0$ $\pm1.3$ 13.8k 2 ABLIKIM 2011 I BES3 ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ , ${{\mathit \gamma}}{{\mathit K}^{+}}{{\mathit K}^{-}}$ $0.2$ $\pm1.5$ $\pm0.4$ 19.8k 3 ARTUSO 2009 CLEO ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}{{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$ $-5.1$ ${}^{+5.4}_{-3.6}$ 721 2 ABLIKIM 2004 I BES2 ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ , ${{\mathit \gamma}}{{\mathit K}^{+}}{{\mathit K}^{-}}$ $13.2$ ${}^{+9.8}_{-7.5}$ 441 4 OREGLIA 1982 CBAL ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}{{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$ • • We do not use the following data for averages, fits, limits, etc. • • $1.0$ $\pm1.3$ $\pm0.3$ 19.8k 4 ARTUSO 2009 CLEO ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}{{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$ 1  Correlated with ${{\mathit a}_{{2}}}$, ${{\mathit a}_{{3}}}$, and ${{\mathit b}_{{3}}}$ with correlation coefficients $\rho _{ {{\mathit a}_{{2}}} {{\mathit b}_{{2}}} }$ = $-0.605$, $\rho _{ {{\mathit a}_{{3}}} {{\mathit b}_{{2}}} }$ = $-0.422$, and $\rho _{ {{\mathit b}_{{2}}} {{\mathit b}_{{3}}} }$ = $0.384$. 2  From a fit with floating $\mathit M2$ and $\mathit E3$ amplitudes $\mathit b_{2}$ and $\mathit b_{3}$. 3  From a fit with floating $\mathit M2$ and $\mathit E3$ amplitudes $\mathit a_{2}$, $\mathit b_{2}$, and $\mathit a_{3}$, and $\mathit b_{3}$. 4  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.

$\mathit b_{2}$ = $\mathit M2/\sqrt {\mathit E1{}^{2}+\mathit M2{}^{2}+\mathit E3{}^{2} }$ Magnetic quadrupole fractional transition amplitude ($ 10^{-2} $)

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 ${{\mathit \eta}_{{c}}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit J / \psi}}$ ABLIKIM 2011I PR D84 092006 Higher-Order Multipole Amplitude Measurement in ${{\mathit \psi}^{\,'}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \chi}_{{c2}}}$ ARTUSO 2009 PR D80 112003 Higher-Order Multipole Amplitudes in Charmonium Radiative Transitions ABLIKIM 2004I PR D70 092004 Measurement of the ${{\mathit \chi}_{{c2}}}$ Polarization in ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \chi}_{{c2}}}$ 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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