0000000001287400
AUTHOR
J. C. Nacher
Double Pion Production Reactions
We report on reactions producing two pions induced by real and virtual photons or nucleons. The role of different resonances in these reactions is emphasized. Novel results on coherent 2π photoproduction in nuclei are also reported.
Radiative production of the Λ(1405) resonance in K− collisions on protons and nuclei
We have carried a theoretical study of the K^- p\to M B \gamma reaction with M B = K^-p, \bar{K}^0 n, \pi^- \Sigma^+, \pi^+ \Sigma^-, \pi^0 \Sigma^0, \pi^0 \Lambda, for K^- lab. momenta between 200 and 500 MeV/c, using a chiral unitary approach for the strong K^-p interaction with its coupled channels. The \Lambda(1405) resonance, which is generated dynamically in this approach, shows up clearly in the d\sigma/dM_I spectrum, providing new tests for chiral symmetry and the unitary approach, as well as information regarding the nature of the resonance. The photon detection alone, summing all channels, is shown to reproduce quite accurately the strength and shape of the \Lambda(1405) resonance…
Magnetic moments of the Lambda(1405) and Lambda(1670) resonances
By using techniques of unitarized chiral perturbation theory, where the $\Lambda(1405)$ and $\Lambda(1670)$ resonances are dynamically generated, we evaluate the magnetic moments of these resonances and their transition magnetic moment. The results obtained here differ appreciably from those obtained with existing quark models. The width for the $\Lambda(1670) \to \Lambda(1405) \gamma$ transition is also evaluated leading to a branching ratio of the order of $2 \times 10^{-6}$.