Hexaquark

Dibaryons are a large family of hypothetical particles that would consist of six quarks of any flavours. They are predicted to be fairly stable once formed. Robert Jaffe proposed the existence of a possibly stable H dibaryon (with the quark composition udsuds), made by combining two uds hyperons, in 1977.

A number of experiments have been suggested to detect dibaryon decays and interactions. Several candidate dibaryon decays were observed but not confirmed in the 1990s.

There is a theory that strange particles such as hyperons and H dibaryons could form in the interior of a neutron star, changing its mass-radius ratio in ways that might be detectable. Conversely, measurements of neutron stars set constraints on possible dibaryon properties. Theory suggests that a large fraction of neutrons could turn into hyperons and merge into dibaryons during the early part of a neutron star to black hole collapse. These dibaryons would very quickly dissolve into quark-gluon plasma during the collapse, or go into some currently unknown state of matter.

External links

• Perhaps a Stable Dihyperon Subscription or purchase required
• Ultrahigh-energy cosmic rays and stable H dibaryon
• Upper limits for a narrow dibaryon in pp collisions at 200 and 310 MeV
• THE E896 EXPERIMENT SEARCH FOR THE H-DIBARYON (PDF)
• Can Doubly Strange Dibaryon Resonances be Discovered at RHIC?
• SEARCH FOR THE WEAK DECAY OF AN H DIBARYON "Our search has yielded two candidate events..."
• Neutron Star Constraints on the H Dibaryon