Editorial Note:<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>N</mml:mi><mml:mo>→</mml:mo><mml:mi>Δ</mml:mi></mml:math>transition and proton polarizabilities from measurements of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>p</mml:mi><mml:mo>(</mml:mo><mml:mrow><mml:mrow><mml:mover><mml:mrow><mml:mi>γ</mml:mi></mml:mrow><mml:mrow><mml:mo>→</mml:mo></mml:mrow></mml:mover></mml:mrow></mml:mrow><mml:mo>,</mml:mo><mml:mi>γ</mml:mi><mml:mo>)

“…In the limit of a real photon (q 2 = 0), the amplitude S 1/2 vanishes. The best determinations of the helicity amplitudes A 1/2 , A 3/2 for the real photon coupling were obtained in pion photoproduction experiments by the CLAS [9], MAMI/A2 [10,11] and LEGS [12,13] Collaborations.…”

Section: A ∆ Properties and Electromagnetic Form Factorsmentioning

confidence: 99%

Δ(1232) Dalitz decay in proton-proton collisions at T=1.25 GeV measured with HADES at GSI

Adamczewski-Musch¹,

Arnold²,

Atomssa³

et al. 2017

Phys. Rev. C

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We report on the investigation of ∆(1232) production and decay in proton-proton collisions at a kinetic energy of 1.25 GeV measured with HADES. Exclusive dilepton decay channels ppe + e − and ppe + e − γ have been studied and compared with the partial wave analysis of the hadronic ppπ 0 channel. They allow to access both ∆ + → pπ 0 (e + e − γ) and ∆ + → pe + e − Dalitz decay channels. The perfect reconstruction of the well known π 0 Dalitz decay serves as a proof of the consistency of the analysis. The ∆ Dalitz decay is identified for the first time and the sensitivity to N-∆ transition form factors is tested. The ∆(1232) Dalitz decay branching ratio is also determined for the first time; our result is (4.19 ± 0.62 syst. ± 0.34 stat.) × 10 −5 , albeit with some model dependence.

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“…Together with pion scattering off the nucleon, single pion photoproduction is the most suitable process for studying the low-lying baryon spectrum. In fact, in recent years the experimental database [6] has increased considerably and many experimental programs have been run at different facilities such as LEGS (Brookhaven) [7] and MAMI (Mainz) [8].…”

Section: Introductionmentioning

confidence: 99%

Properties of nucleon resonances by means of a genetic algorithm

et al. 2008

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We present an optimization scheme that employs a genetic algorithm (GA) to determine the properties of low-lying nucleon excitations within a realistic photo-pion production model based upon an effective Lagrangian. We show that with this modern optimization technique it is possible to reliably assess the parameters of the resonances and the associated error bars as well as to identify weaknesses in the models. To illustrate the problems the optimization process may encounter, we provide results obtained for the nucleon resonances (1230) and (1700). The former can be easily isolated and thus has been studied in depth, while the latter is not as well known experimentally.

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Editorial Note:N→Δtransition and proton polarizabilities from measurements ofp(γ→,γ)

Cited by 100 publications

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Improved empirical parametrizations of theγN→Δ(1232)andγN<

Improved empirical parametrizations of theγN→Δ(1232)andγN<

Δ(1232) Dalitz decay in proton-proton collisions at T=1.25 GeV measured with HADES at GSI

Properties of nucleon resonances by means of a genetic algorithm

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Editorial Note:N→Δtransition and proton polarizabilities from measurements ofp(γ→,γ)

Cited by 100 publications

References 0 publications

Improved empirical parametrizations of theγ*N→Δ(1232)andγ*N<

Improved empirical parametrizations of theγ*N→Δ(1232)andγ*N<

Δ(1232) Dalitz decay in proton-proton collisions at T=1.25 GeV measured with HADES at GSI

Properties of nucleon resonances by means of a genetic algorithm

Contact Info

Product

Resources

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Improved empirical parametrizations of theγN→Δ(1232)andγN<

Improved empirical parametrizations of theγN→Δ(1232)andγN<