6533b831fe1ef96bd1299778

RESEARCH PRODUCT

ΛNNandΣNNsystems at threshold

subject

description

We calculate the hypertriton binding energy and the $\ensuremath{\Lambda}d$ and $\ensuremath{\Sigma}d$ scattering lengths using baryon-baryon interactions obtained from a chiral constituent quark model. We study consistently the $\ensuremath{\Lambda}\mathit{NN}$ and $\ensuremath{\Sigma}\mathit{NN}$ systems by analyzing the effect of the $\ensuremath{\Sigma}\ensuremath{\leftrightarrow}\ensuremath{\Lambda}$ conversion. Our interactions correctly predict the hypertriton binding energy. The $(I,J)=(0,3/2)$ $\ensuremath{\Lambda}\mathit{NN}$ channel is also attractive and it might have a bound state. From the condition of nonexistence of a (0,3/2) $\ensuremath{\Lambda}\mathit{NN}$ bound state, an upper limit for the spin-triplet $\ensuremath{\Lambda}N$ scattering length is obtained. We also present results for the elastic and inelastic $\ensuremath{\Sigma}N$ and $\ensuremath{\Lambda}N$ cross sections. The consistent description of the $\ensuremath{\Sigma}N$ scattering cross sections imposes a lower limit for the corresponding spin-triplet scattering lengths. In the $\ensuremath{\Sigma}\mathit{NN}$ system the only attractive channels are $(I,J)=(1,1/2)$ and $(0,1/2)$, the $(1,1/2)$ state being the most attractive one.