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   JSON  (beta) 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
2017N
 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
1993E
 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