Strangeness in the Universe? Low-energy kaon-nuclei interaction studies with AMADEUS at the DAΦNE collider

The AMADEUS experiment aims to provide unique quality data of K⁻ hadronic interactions in light nuclear targets, in order to solve fundamental open questions in the non-perturbative strangeness QCD sector, like the controversial nature of the Λ(1405) state, the yield of hyperon formation below threshold, the yield and shape of multi-nucleon K⁻ absorption space. These processes are intimately connected to the possible existence of exotic antikaon multi-nucleon clusters and might play a role in neutron stars. AMADEUS takes advantage of the DAΦNE collider, which provides a unique source of monochromatic low-momentum kaons, and exploited in a first phase the KLOE detector as an active target, in order to obtain excellent acceptance and resolution data for K⁻ nuclear capture on H, ⁴He, and ¹²C, both at-rest and in-flight. During the second half of 2012 a successful data taking was performed with a dedicated pure carbon target implemented in the central region of KLOE, providing a high statistics sample of at-rest K⁻ nuclear interactions. AMADEUS has the capacity to investigate the role of the strangeness in the Universe. (author)