The anticharmed exotic baryon Thetac and its relatives

الأصل · EN

Motivated by the recent discovery of the exotic S=+1 narrow baryon resonance Theta+ at 1540 MeV, with quark content uudd sbar, we conjecture the existence of its anti-charmed analogue Thetac, with quark content uudd cbar, and compute its likely properties. We rely on the recently constructed model of a novel kind of a pentaquark with an unusual color structure which provides a good approximation to the Theta+ mass. We expect that Thetac is an isosinglet with Jᵖ=1/2+ and estimate its mass at 2985 ± 50 MeV. We also discuss another possible exotic baryon resonance containing heavy quarks, the Thetab+, a uudd bbar state, and estimate mThetab+=6398 ± 50 MeV. These states should appear as unexpectedly narrow peaks in D-p, Dbar⁰ n, B⁰ p and B+ n mass distributions.