nLab tetraquark



Fields and quanta

fields and particles in particle physics

and in the standard model of particle physics:

force field gauge bosons

scalar bosons

matter field fermions (spinors, Dirac fields)

flavors of fundamental fermions in the
standard model of particle physics:
generation of fermions1st generation2nd generation3d generation
quarks (qq)
up-typeup quark (uu)charm quark (cc)top quark (tt)
down-typedown quark (dd)strange quark (ss)bottom quark (bb)
neutralelectron neutrinomuon neutrinotau neutrino
bound states:
mesonslight mesons:
pion (udu d)
ρ-meson (udu d)
ω-meson (udu d)
ϕ-meson (ss¯s \bar s),
kaon, K*-meson (usu s, dsd s)
eta-meson (uu+dd+ssu u + d d + s s)

charmed heavy mesons:
D-meson (uc u c, dcd c, scs c)
J/ψ-meson (cc¯c \bar c)
bottom heavy mesons:
B-meson (qbq b)
ϒ-meson (bb¯b \bar b)
proton (uud)(u u d)
neutron (udd)(u d d)

(also: antiparticles)

effective particles

hadrons (bound states of the above quarks)


in grand unified theory

minimally extended supersymmetric standard model




dark matter candidates


auxiliary fields



A tetraquark is an exotic meson which is a bound state of four quarks, or rather: of a diquark and an anti-diquark.



The idea of tetraquarks is mentioned already in the original articles on quarks.

The original proposal for tetraquarks with two heavy quark constitutents?:

and fully heavy tetraquarks:

See also:

Via hadron supersymmetry

Discussion in view of hadron supersymmetry and diquark-models:

in holographic light front QCD:

in regards to experimental results:

Experimental detection

Fully charmed tetraquark

Experimental detection of a tetraquark resonance X(6900)X(6900) made entirely of four charm quarks and argued to be the first observed “true” tetraquark state (instead of just a “diquark molecule”):

Popular exposition:

Theoretical explanation:

  • Ming-Sheng liu, Feng-Xiao Liu, Xian-Hui Zhong, Qiang Zhao, Full-heavy tetraquark states and their evidences in the LHCb di-J/ψ spectrum (arXiv:2006.11952)

  • Qi-Fang Lü, Dian-Yong Chen, Yu-Bing Dong, Masses of fully heavy tetraquarks QQQ¯Q¯Q Q \overline{Q} \overline{Q} in an extended relativized quark model, Eur. Phys. J. C 80, 871 (2020) (arXiv:2006.14445, doi:10.1140/epjc/s10052-020-08454-1)

reviewed in:

T cc +T^+_{c c} tetraquark

Indication of a tetraquark ccu¯d¯c c \bar u \bar d with two charm quarks, and anti-up quark and an anti-down quark:

Further discussion:

  • Sean Fleming, Reed Hodges, Thomas Mehen, T cc +T_{c c}^+ Decays: Differential Spectra and Two-Body Final States (arXiv:2109.02188)

  • Huimin Ren, Fan Wu, Ruilin Zhu, Hadronic molecule interpretation of T cc +T_{c c}^+ and its beauty-partners (arXiv:2109.02531)

Last revised on September 7, 2021 at 07:07:19. See the history of this page for a list of all contributions to it.