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

$\boldsymbol b_{2}$ = $\boldsymbol M2/\sqrt {\boldsymbol E1{}^{2}+\boldsymbol M2{}^{2} }$ Magnetic quadrupole fractional transition amplitude INSPIRE search

VALUE ($ 10^{-2} $)

EVTS

DOCUMENT ID

TECN

COMMENT

$\bf{ 2.5 \pm0.4}$

OUR AVERAGE

$2.29$ $\pm0.39$ $\pm0.27$

164k

ABLIKIM

2017

BES3

${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}{{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$

$2.76$ $\pm0.73$ $\pm0.23$

39k

ARTUSO

2009

CLEO

${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}{{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$

$7.7$ ${}^{+5.0}_{-4.5}$

921

OREGLIA

1982

CBAL

${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}{{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$

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 ${{\mathit \psi}{(3686)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \chi}_{{c1,2}}}$ 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

OREGLIA

1982

PR D25 2259

Study of the Reaction ${{\mathit \psi}^{\,'}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}{{\mathit J / \psi}}$