Calculating the binding energy between hyperon particles
contributes to understanding a new type of neutron star. In
2009, physicists from Japan’s KEK high-energy proton accelerator
announced the sighting of a rare event: an unusually bulky
beryllium nucleus that, in addition to four protons and five
neutrons, contained two particles called 'hyperons'. Now, Emiko
Hiyama at the RIKEN Nishina Center for Accelerator-Based
Science, Wako, and her colleagues from several Japanese
universities have presented a calculation that provides the most
precise description available of the interactions between nuclei
and hyperons in the double-hyperon beryllium nucleus observed at
KEK1. Hyperons—particles that contain at least one so-called
‘strange’ quark—exist for less than a billionth of a second
before they decay. Scientists know relatively little about how
hyperons interact with matter, but speculate that the hot, dense
environment of a neutron star would allow these particles to
exist in an almost stable state. If they