Helicity Amplitudes of the Lambda(1670) and two Lambda(1405) as dynamically generated resonances

Abstract

We determine the helicity amplitudes A_1/2 and radiative decay widths in the transition Lambda(1670) to gamma Y (Y=Lambda or Sigma^0). The Lambda(1670) is treated as a dynamically generated resonance in meson-baryon chiral dynamics. We obtain the radiative decay widths of the Lambda(1670) to gamma Lambda as 3 \pm 2 keV and to gamma Sigma^0 as 120 \pm 50 keV. Also, the Q^2 dependence of the helicity amplitudes A_1/2 is calculated. We find that the K Xi component in the Lambda(1670) structure, mainly responsible for the dynamical generation of this resonance, is also responsible for the significant suppression of the decay ratio Gamma_{gamma Lambda}/Gamma_{gamma Sigma^0}. A measurement of the ratio would, thus, provide direct access to the nature of the Lambda(1670). To compare the result for the Lambda(1670), we calculate the helicity amplitudes A_1/2 for the two states of the Lambda(1405). Also, the analytic continuation of Feynman parameterized integrals of more complicated loop amplitudes to the complex plane is developed which allows for an internally consistent evaluation of A_1/2.

15 pages, 8 figures

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Cited by in corpus (17)

• The nature of the Lambda(1405) resonance in chiral dynamics
• Coupled-channel dynamics in the reactions piN --> piN, etaN, KLambda, KSigma
• Comprehensive analysis of the wave function of a hadronic resonance and its compositeness
• Photocouplings at the Pole from Pion Photoproduction
• Internal structure of resonant Lambda(1405) state in chiral dynamics
• Relevance of complex branch points for partial wave analysis
• The pole structure of the Lambda(1405) in a recent QCD simulation
• Strategy to find the two $\Lambda (1405)$ states from lattice QCD simulations
• Valence quark and meson cloud contributions for the gamma* Lambda -> Lambda* and gamma* Sigma0 -> Lambda* reactions
• Light-quark contributions to the magnetic form factor of the Lambda(1405)
• S- and p-wave structure of $S=-1$ meson-baryon scattering in the resonance region
• Determination of compositeness of the Lambda(1405) resonance from its radiative decay
• Baryon transition form factors at the pole
• New insights into the pole parameters of the $\Lambda (1380)$, the $\Lambda (1405)$ and the $\Sigma (1385)$
• Low energy reaction $K^{-}p\to \Lambda \eta$ and the negative parity $\Lambda$ resonances
• Global Data-Driven Determination of Baryon Transition Form Factors
• Singlet baryons in the graded symmetry approach to partially quenched QCD