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Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/28695
Title: Helicity amplitudes of the Lambda(1670) and two Lambda(1405) as dynamically generated resonances
Authors: Oset, Eulogi; Jido, D.; Döring, Michael
Issue Date: Sep-2010
Publisher: Springer
Citation: European Physical Journal A - Hadrons and Nuclei 45 (3): 319-333 (2010)
Abstract: We determine the helicity amplitudes A(1/2) and radiative decay widths in the transition Lambda(1670) -> 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 2 +/- 1 keV and to -gamma Sigma(0) as 120 +/- 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 A)/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 Lambda(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).
Publisher version (URL): http://dx.doi.org/10.1140/epja/i2010-11015-0
URI: http://hdl.handle.net/10261/28695
DOI: 10.1140/epja/i2010-11015-0
ISSN: 1434-6001
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