Based on complex simulations of quantum chromodynamics performed using the K computer, one of the most powerful computers in the world, the HAL QCD Collaboration, made up of scientists from the RIKEN Nishina Center for Accelerator-based Science and the RIKEN Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS) program, together with colleagues from a number of universities, have predicted a new type of “dibaryon”—a particle that contains six quarks instead of the usual three. Studying how these elements form could help scientists understand the interactions among elementary particles in extreme environments such as the interiors of neutron stars or the early universe moments after the Big Bang.
Particles known as “baryons”—principally protons and neutrons—are composed of three quarks bound tightly together, with their charge depending on the “color” of the quarks that make them up. A dibaryon is essentially a system with two baryons. There is one known dibaryon in nature—deuteron, a deuterium (or heavy-hydrogen) nucleus that contains a proton and a neutron that are very lightly bound. Scientists have long wondered whether there could be other types of dibaryons. Despite searches, no other dibaryon has been found.
The group, in work published in Physical Review Letters, has now used powerful theoretical and computational tools to predict the existence of a “most strange” dibaryon, made up of two “Omega baryons” that contain three strange quarks each. They named it “di-Omega”. The group also suggested a way to look for these strange particles through experiments with heavy ion collisions planned in Europe and Japan.