Method to evidence hypernuclear halos from a two-target interaction cross section measurement

We present a two-target measurement method to determine the interaction cross section of hypernuclei with a target nucleus. The method allows to extract from two independent measurements the production cross section of a given hypernucleus as well as its interaction cross section on a specific target. The latter is then further analyzed to deduce the matter radius of the hypernucleus. The sensitivity of the method has been investigated for the specific case of the lightest hyperhalo candidate hypertriton (Λ³H) produced from ¹²C+¹²C collisions at 1.9 GeV/nucleon. Furthermore, its feasibility is demonstrated by detailed simulations for realistic experimental conditions at GSI/FAIR, using a dedicated HYDRA (HYpernuclei Decay at R³B Apparatus) time-projection chamber prototype. A precision of 15% or better in the interaction cross section can be achieved, allowing an extraction of the unknown Λ³H matter radius and assessing its halo or non-halo character.