The doubly heavies: (Qbar Q qbar q), (Q Q qbar qbar) tetraquarks and (Q Q q) baryons

Abstract

Recent discoveries by Belle and BESIII of charged exotic quarkonium-like resonances provide fresh impetus for study of heavy exotic hadrons. In the limit N_c --> infinity, M_Q --> infinity, the (Qbar Q qbar q') tetraquarks (TQ-s) are expected to be narrow and slightly below or above the (Qbar q') and (Q qbar) two-meson threshold. The isoscalar TQ-s manifest themselves by decay to (Qbar Q) pi pi, and the ~30 MeV heavier charged isotriplet TQ-s by decays into (Qbar Q) pi. The new data strongly suggest that the real world with N_c=3, Q=c,b and q,q' = u,d is qualitatively described by the above limit. We discuss the relevant theoretical estimates and suggest new signatures for TQ-s in light of the recent discoveries. We also consider "baryon-like" states (Q Q' qbar qbar'), which if found will be direct evidence not just for near-threshold binding of two heavy mesons, but for genuine tetraquarks with novel color networks. We stress the importance of experimental search for doubly-heavy baryons in this context.

10 pages, LaTeX; JHEP version

References in corpus (11)

• Observation of a charged charmoniumlike structure in e+e- to pi+pi-J/psi at \sqrt{s}=4.26 GeV
• Decoding the riddle of Y(4260) and $Z_c(3900)$
• Consequences of Heavy Quark Symmetries for Hadronic Molecules
• Tetraquark Mesons in Large $N$ Quantum Chromodynamics
• Coupled-channel analysis of the possible $D^{(\ast )}{D}^{(\ast )}$, ${\bar{B}}^{(\ast )}{\bar{B}}^{(\ast )}$ and $D^{(\ast )}{\bar{B}}^{(\ast )}$ molecular states
• A J^PG=1++ Charged Resonance in the Y(4260) to pi+pi- J/psi Decay?
• Measurement of the Bc meson mass in the exclusive decay Bc --> Jpsi Pi
• Predictions of charged charmonium-like structures with hidden-charm and open-strange channels
• The Constituent Quark Model Revisited - Quark Masses, New Predictions for Hadron Masses and KN Pentaquark
• Possibility of Exotic States in the Upsilon system
• Predictions for masses of Xi_b baryons

Cited by in corpus (8)

• Discovery of doubly-charmed Xi_{cc} baryon implies a stable (b b ubar dbar) tetraquark
• New Exotic Meson and Baryon Resonances from Doubly-Heavy Hadronic Molecules
• Baryons with two heavy quarks: Masses, production, decays, and detection
• Novel Six-Quark Hidden-Color Dibaryon States in QCD
• $X(3872)$, $X_b$, and the ${\chi }_{b1}(3P)$ state
• Tetraquarks, their Masses and Decays in QED_2
• SU(3) flavour symmetry breaking and charmed states
• Doubly Heavy Tetraquarks and Baryons