nLab
XYZ particle

Contents

Context

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)
leptons
chargedelectronmuontauon
neutralelectron neutrinomuon neutrinotau neutrino
bound states:
mesonslight mesons:
pion (udu d)
ρ-meson (udu d)
ω-meson (udu d)
f1-meson
a1-meson
strange-mesons:
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)
baryonsnucleons:
proton (uud)(u u d)
neutron (udd)(u d d)

(also: antiparticles)

effective particles

hadrons (bound states of the above quarks)

solitons

in grand unified theory

minimally extended supersymmetric standard model

superpartners

bosinos:

sfermions:

dark matter candidates

Exotica

auxiliary fields

Contents

Idea

XYZ particles are charmonium-like exotic mesons which are increasingly being observed in experiment (typically in B-meson-experiments such as Belle, LHCb, , BaBar), but whch are hard to interpret as bound states in the traditional quark model (in theoretical physics) of quantum chromodynamics.

References

Review:

  • Stephen Godfrey and Stephen L. Olsen, The Exotic XYZ Charmonium-Like Mesons, Annual Review of Nuclear and Particle Science Vol. 58:51-73 (Volume publication date 23 November 2008) (arXiv:10.1146/annurev.nucl.58.110707.171145)

  • Xiang Liu, An overview of XYZ new particles, Chin. Sci. Bull. 59, 3815-3830 (2014) (arXiv:1312.7408)

  • Stephen Lars Olsen, The XYZ mesons: what they aren’t, EPJ Web of Conferences 202, 01003 (2019) (doi:10.1051/epjconf/201920201003)

  • Nora Brambilla, Simon Eidelman, Christoph Hanhart, Alexey Nefediev, Cheng-Ping Shen, Christopher E. Thomas, Antonio Vairo, Chang-Zheng Yuan, The XYZ states: experimental and theoretical status and perspectives, Physics Reports 2020 (arXiv:1907.07583)

See also

For references specifically on tetraquarks see there.

Discussion of exotic hadrons via hadron supersymmetry:

Last revised on August 27, 2021 at 12:31:23. See the history of this page for a list of all contributions to it.