# Valence quark and meson cloud contributions for the gamma* Lambda -> Lambda* and gamma* Sigma0 -> Lambda* reactions

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Valence quark and meson cloud contributions for the gamma* Lambda -> Lambda* and gamma* Sigma0 -> Lambda* reactions**

We estimate the valence quark contributions for the gamma* Y - Lambda* Y=Lambda, Sigma0 electromagnetic transition form factors. We focus particularly on the case Lambda*=Lambda1670 as an analog reaction with gamma* N - N1535. The results are compared with those obtained from chiral unitary model, where the Lambda* resonance is dynamically generated and thus the electromagnetic structure comes directly from the meson cloud excitation of the baryon ground states. The form factors for the case Y=Sigma0 in particular, depend crucially on the two real phase sign combination, a phase between the Lambda and Lambda* states, and the other, the phase between the Lambda and Sigma0 radial wave functions. Depending on the combination of these two phases, the form factors for the gamma* Sigma0 - Lambda* reaction can be enhanced or suppressed. Therefore, there is a possibility to determine the phase combination by experiments.

Author: **G. Ramalho; D. Jido; K. Tsushima**

Source: https://archive.org/