An introduction to the quark model

Few-charge systems History of the quark model Mesons Baryons Multiquarks and other exotics Outlook
Chromomagnetic binding
In 1987, Lipkin, and Gignoux et al. realised that
P = ( ¯ Qqqqq)
with (qqqq) = (uuds) or (udds) or (udss)
has the same 150 MeV binding below the [( ¯ Qq) + (qqq)]
threshold in the limit where mQ → ∞ and same assumptions
than Jaffe for the light quark
This was named “pentaquark” (now, one should say: “the
chromomagnetic pentaquark”)
It was searched for in 1 experiment at Fermilab (Ashery et al.),
not conclusive
A re-analysis, including mQ < ∞, indicate that relaxing the the P
likely becomes unbound
Other configurations analysed, see Leandri et al.
JMR Quark Model