${{\mathit \Delta}{(1232)}}$ BREIT-WIGNER PHOTON DECAY AMPLITUDES

Papers on ${{\mathit \gamma}}{{\mathit N}}$ amplitudes predating 1981 may be found in our 2006 edition, Journal of Physics G33 1 (2006).

${{\mathit \Delta}{(1232)}}$ $\rightarrow$ ${{\mathit N}}{{\mathit \gamma}}$, ${{\mathit E}_{{{2}}}}/{{\mathit M}_{{{1}}}}$ ratio

INSPIRE   PDGID:
B033EMR
VALUE DOCUMENT ID TECN  COMMENT
$\bf{ -0.030\text{ to }-0.020\text{ }(\approx-0.025) }$ OUR ESTIMATE
$-0.0274$ $\pm0.0003$ $\pm0.0030$
AHRENS
2004A
DPWA $\vec\gamma\vec {{\mathit p}}$ $\rightarrow$ ${{\mathit N}}{{\mathit \pi}}$
$-0.020$ $\pm0.002$
ARNDT
2002
DPWA ${{\mathit \gamma}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit N}}{{\mathit \pi}}$
$-0.0307$ $\pm0.0026$ $\pm0.0024$
BLANPIED
2001
LEGS ${{\mathit \gamma}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit p}}{{\mathit \gamma}}$, ${{\mathit p}}{{\mathit \pi}^{0}}$, ${{\mathit n}}{{\mathit \pi}^{+}}$
$-0.016$ $\pm0.004$ $\pm0.002$
GALLER
2001
DPWA ${{\mathit \gamma}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit \gamma}}{{\mathit p}}$
$-0.025$ $\pm0.001$ $\pm0.002$
BECK
2000
IPWA $\vec\gamma$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit p}}{{\mathit \pi}^{0}}$, ${{\mathit n}}{{\mathit \pi}^{+}}$
$-0.0233$ $\pm0.0017$
HANSTEIN
1998
IPWA ${{\mathit \gamma}}$ ${{\mathit N}}$ $\rightarrow$ ${{\mathit \pi}}{{\mathit N}}$
$-0.015$ $\pm0.005$ 1
ARNDT
1997
IPWA ${{\mathit \gamma}}$ ${{\mathit N}}$ $\rightarrow$ ${{\mathit \pi}}{{\mathit N}}$
$-0.0319$ $\pm0.0024$
DAVIDSON
1997
DPWA ${{\mathit \gamma}}$ ${{\mathit N}}$ $\rightarrow$ ${{\mathit \pi}}{{\mathit N}}$
• • We do not use the following data for averages, fits, limits, etc. • •
$-0.022$
DRECHSEL
2007
DPWA ${{\mathit \gamma}}$ ${{\mathit N}}$ $\rightarrow$ ${{\mathit \pi}}{{\mathit N}}$
$-0.026$
PENNER
2002D
DPWA Multichannel
$-0.0254$ $\pm0.0010$
HANSTEIN
1998
DPWA ${{\mathit \gamma}}$ ${{\mathit N}}$ $\rightarrow$ ${{\mathit \pi}}{{\mathit N}}$
$-0.025$ $\pm0.002$ $\pm0.002$
BECK
1997
IPWA ${{\mathit \gamma}}$ ${{\mathit N}}$ $\rightarrow$ ${{\mathit \pi}}{{\mathit N}}$
$-0.030$ $\pm0.003$ $\pm0.002$
BLANPIED
1997
DPWA ${{\mathit \gamma}}$ ${{\mathit N}}$ $\rightarrow$ ${{\mathit \pi}}{{\mathit N}}$, ${{\mathit \gamma}}{{\mathit N}}$
1  This ARNDT 1997 value is very sensitive to the database being fitted. The result is from a fit to the full pion photoproduction database, apart from the BLANPIED 1997 cross-section measurements.
References