Speaker
Description
We propose a new method to measure the evolution of the neutron skin thickness between different isotopes. We consider antiproton--nucleus interactions close to the production threshold of $\Lambda \overline{\Lambda }$ and $\Sigma^-\overline{\Lambda }$ pairs. At low energies, $\Lambda \overline{\Lambda }$ pairs are produced in $\overline{\text{p}} +\text{p}$ collisions, while $\Sigma^-\overline{\Lambda }$ pairs can only be produced in $\overline{\text{p}} +\text{n}$ interactions.
Within a simple geometrical picture we show that the production ratios for $\Sigma^-\overline{\Lambda }$ and $\Lambda \overline{\Lambda }$ pairs for two different isotopes are directly related to the variation of the neutron skin thickness for the two nuclei. Performing high statistics calculations with the Gie\ss en Boltzmann--Uehling--Uhlenbeck (GiBUU) transport model for several isotope pairs we verify a strong connection between double ratio of the
$\Lambda \overline{\Lambda }$ and $\Sigma^-\overline{\Lambda }$ production probabilities and the difference of the neutron skin.
