MULTIPOLE AMPLITUDE RATIOS IN RADIATIVE DECAYS ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \chi}_{{{cJ}}}{(1P)}}$ and ${{\mathit \chi}_{{{cJ}}}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit J / \psi}{(1S)}}$

$\mathit a_{2}({{\mathit \chi}_{{{c1}}}})/\mathit a_{2}({{\mathit \chi}_{{{c2}}}}$) Magnetic quadrupole transition amplitude ratio

INSPIRE   JSON  (beta) PDGID:
M071QAR
VALUE ($ 10^{-2} $) EVTS DOCUMENT ID TECN  COMMENT
$\bf{ 63 \pm7}$ OUR AVERAGE
$61.7$ $\pm8.3$ 253k 1
ABLIKIM
2017N
 BES3 ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}{{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$
$67$ ${}^{+19}_{-13}$ 59k 2
ARTUSO
2009
CLEO ${{\mathit \psi}{(2S)}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit \gamma}}{{\mathit \ell}^{+}}{{\mathit \ell}^{-}}$
1  Statistical and systematic errors combined.
2  Statistical and systematic errors combined. Using values from fits with floating $\mathit M2$ amplitudes $\mathit a_{2}({{\mathit \chi}_{{{c1}}}}$), $\mathit a_{2}({{\mathit \chi}_{{{c2}}}}$), $\mathit b_{2}({{\mathit \chi}_{{{c1}}}}$), $\mathit b_{2}({{\mathit \chi}_{{{c2}}}}$) and fixed $\mathit E3$ amplitudes of $\mathit a_{3}({{\mathit \chi}_{{{c2}}}}$) = $\mathit b_{3}({{\mathit \chi}_{{{c2}}}}$) = 0. Not independent of values for $\mathit a_{2}({{\mathit \chi}_{{{c1}}}{(1P)}}$) and $\mathit a_{2}({{\mathit \chi}_{{{c2}}}{(1P)}}$) from ARTUSO 2009.
References