Theta meson

Not to be confused with the θ⁺ of the τ–θ puzzle, which is now identified as kaon, or with the Θ⁺ and
Θ⁺
_c, formerly thought to be pentaquarks.

The theta meson (
θ
)^[1] is a hypothetical form of quarkonium (i.e. a flavourless meson) formed by a top quark (
t
) and top antiquark (
t
). As a P-odd and C-odd
t

t
state, it is analogous to the
ϕ
(
s

s
),
J/ψ
(
c

c
) and
ϒ
(
b

b
) mesons. Due to the top quark's short lifetime, the theta meson is expected to not be observed in nature.^[2]

Theta meson

Composition	t t
Statistics	bosonic
Interactions	strong, weak, gravitational, electromagnetic
Status	hypothetical
Antiparticle	self
Electric charge	0 e
Isospin	0
Hypercharge	0
Parity	−1
C parity	−1

See also

• List of mesons

References

1. Roos, M.; Wohl, C.G. "Naming Scheme for Hadrons" (PDF). lbl.gov. Retrieved 23 March 2022.
2. Fabiano, N. (1998). "Top mesons". European Physical Journal C. 2 (2): 345–350. arXiv:hep-ph/9704261. Bibcode:1998EPJC....2..345F. doi:10.1007/s100520050144. S2CID 17321939.