TY  - JOUR
AU  - Doring, M.
AU  - Jido, D.
AU  - Oset, E.
PY  - 2010
DA  - 2010//
TI  - Helicity amplitudes of the Lambda(1670) and two Lambda(1405) as dynamically generated resonances
T2  - Eur. Phys. J. A
JO  - European Physical Journal A
SP  - 319
EP  - 333
VL  - 45
IS  - 3
PB  - Springer
AB  - 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).
SN  - 1434-6001
UR  - http://arxiv.org/abs/1002.3688
UR  - https://doi.org/10.1140/epja/i2010-11015-0
DO  - 10.1140/epja/i2010-11015-0
LA  - English
N1  - ISI:000281972900006
ID  - Doring_etal2010
ER  -