${{\mathit \Delta}{(1232)}}$ 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 search

B033EMR
VALUE DOCUMENT ID TECN  COMMENT
$\bf{ -0.028\text{ to }-0.022\text{ }(\approx-0.025) }$ OUR ESTIMATE
$-0.0238$ $\pm0.0016$ $\pm0.0010$
MORNACCHI
2024
DPWA $\vec\gamma\vec {{\mathit p}}$ $\rightarrow$ ${{\mathit N}}{{\mathit \pi}}$
$-0.0274$ $\pm0.0003$ $\pm0.0030$
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:
MORNACCHI 2024
PR C109 055201 Evaluation of the E2/M1 ratio in the $N\to \Delta(1232)$ transition from the $ \vec{\gamma} \vec{p} \to p \pi^0 $ reaction
DRECHSEL 2007
EPJ A34 69 Unitary Isobar Model $−$ MAID2007
AHRENS 2004A
EPJ A21 323 Helicity Dependence of the ${{\mathit \gamma}}$ ${{\mathit p}}$ $\rightarrow$ ${{\mathit N}}{{\mathit \pi}}$ Channels and Multipole Analysis in the ${{\mathit \Delta}}$ Region
ARNDT 2002
PR C66 055213 Analysis of Pion Photoproduction Data
PENNER 2002D
PR C66 055212 Vector Meson Production and Nucleon Resonance Analysis in a Coupled Channel Approach for Energies ${\mathit m}_{{{\mathit N}}}$ $<$ $\sqrt {s }$ $<$ 2 GeV. 2. Photon Induced Results
BLANPIED 2001
PR C64 025203 ${{\mathit N}}$ $\rightarrow$ ${{\mathit \Delta}}$ Transition and Proton Polarizabilities from Measurements of ${{\mathit p}}$ (${{\mathit \gamma}}↑$, ${{\mathit \gamma}}$), ${{\mathit p}}$ (${{\mathit \gamma}}↑$, ${{\mathit \pi}^{0}}$), and ${{\mathit p}}$ (${{\mathit \gamma}}↑$, ${{\mathit \pi}^{+}}$)
GALLER 2001
PL B503 245 Compton Scattering by the Proton
BECK 2000
PR C61 035204 Determination of the $\mathit E2/\mathit M$1 Ratio in the ${{\mathit \gamma}}$ ${{\mathit N}}$ $\rightarrow$ ${{\mathit \Delta}{(1232)}}$ Transition from a Simultaneous Measurement of ${{\mathit p}}({{\mathit \gamma}}↑$, ${{\mathit p}}){{\mathit \pi}^{0}}$ and ${{\mathit p}}({{\mathit \gamma}}↑$, ${{\mathit \pi}^{+}}){{\mathit n}}$
HANSTEIN 1998
NP A632 561 Multipole Analysis of Pion Photoproduction Based on Fixed $\mathit t$ Dispersion Relations and Unitarity
ARNDT 1997
PR C56 577 Pion Photoproduction in the ${{\mathit \Delta}}$ Resonance Region
BECK 1997
PRL 78 606 Measurement of the $\mathit E2/\mathit M$1 Ratio in the ${{\mathit N}}$ $\rightarrow$ ${{\mathit \Delta}}$ Transition using the Reaction ${{\mathit p}}$ (${{\mathit \gamma}}↑$, ${{\mathit p}}$) ${{\mathit \pi}^{0}}$
Also
PRL 79 4510 Replay on BECK 1997 Measurement of the $\mathit E2/\mathit M$1 Ratio in the ${{\mathit N}}$ $\rightarrow$ ${{\mathit \Delta}}$ Transition using the Reaction ${{\mathit p}}$ (${{\mathit \gamma}}↑$, ${{\mathit p}}$) ${{\mathit \pi}^{0}}$
Also
PRL 79 4512 Measurement of the $\mathit E2/\mathit M$1 Ratio in the ${{\mathit N}}$ $\rightarrow$ ${{\mathit \Delta}}$ Transition using the Reaction ${{\mathit p}}$ (${{\mathit \gamma}}↑$, ${{\mathit p}}$) ${{\mathit \pi}^{0}}$
Also
PRL 79 4515 (errat.) Erratum: (BECK 1997) Measurement of the $\mathit E2/\mathit M$1 Ratio in the ${{\mathit N}}$ $\rightarrow$ ${{\mathit \Delta}}$ Transition using the Reaction ${{\mathit p}}$ (${{\mathit \gamma}}↑$, ${{\mathit p}}$) ${{\mathit \pi}^{0}}$
BLANPIED 1997
PRL 79 4337 ${{\mathit n}}$ $\rightarrow$ ${{\mathit \Delta}}$ Transition from Simultaneous Measurements of ${{\mathit p}}$ (${{\mathit \gamma}}$, ${{\mathit \pi}}$) and ${{\mathit p}}$ (${{\mathit \gamma}}↑$, ${{\mathit \gamma}}$)
DAVIDSON 1997
PRL 79 4509 Mainz Measurement of the $\mathit E2/\mathit M$1 Ratio in the ${{\mathit N}}$ $−$ ${{\mathit \Delta}}$ Transition. (A Comment on the Letter by R.Beck $\mathit et~al$, PRL 78, 606 (BECK 1997))