Narrow Results

The aim of the AMADEUS collaboration is to provide new experimental constraints to the antikaon-nucleon ($\bar{K}N$) strong interaction in the regime of nonperturbative QCD, investigating the low-energy $K^{-}$ hadronic interactions with light nuclei like H, ⁴He, ⁹Be and ${}^{12}$C. The unique low-momentum kaon beam produced at the DA$\mathrm{\Phi }$NE collider is ideal to study $K^{-}$ nuclear captures, both at-rest and in-flight. The large acceptance KLOE detector, used as an active target, allows to achieve excellent position and momentum resolutions. In this work, a brief description of recent AMADEUS results is presented.

The article reviews our recent experimental results on the Continuous Spontaneous Localization (CSL) model and on the gravity related collapse model developed by Diósi and Penrose (DP). These models of dynamical reduction of the wave function consist in non-linear and stochastic modifications of the Schröedinger equation, which lead to a progressive breakdown of the superposition principle, as the size of the system increases. We performed a high sensitivity survey of the spontaneous radiation phenomenon, predicted by the collapse models, in a dedicated experiment operated in the extremely low background of the Gran Sasso underground National Laboratory of INFN in Italy. Our studies set the strongest bounds on the CSL parameters, in a broad region of the parameters space, and rule out the DP in its present formulation.