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Omega meson

## Summary

Composition ${\textstyle \approx {\frac {u{\bar {u}}+d{\bar {d}}}{\sqrt {2}}}}$ Bosonic Mesons Strong, weak, electromagnetic, gravity ω Self Yoichiro Nambu[1] (1957) Lawrence Berkeley National Laboratory (1961)[2][3] 1 782.66±0.13 MeV/c2 (7.58±0.11)×10−23 s π++π0+π− or π0+γ 0 e 1 0 0 −1 −1

The omega meson (
ω
) is a flavourless meson formed from a superposition of an up quarkantiquark and a down quark–antiquark pair. It is part of the vector meson nonet[4][5] and mediates the nuclear force along with pions and rho mesons.

## Properties

The most common decay mode for the ω meson is
π+

π0

π
at 89.2±0.7%, followed by
π0

γ
at 8.34±0.26%.[6]

Particle name Particle
symbol
Antiparticle
symbol
Quark
content
Rest mass (MeV/c2) IG JPC S C B' Mean lifetime (s) Commonly decays to

(>5% of decays)

Omega meson[6]
ω
(782)
Self ${\textstyle {\frac {u{\bar {u}}+d{\bar {d}}}{\sqrt {2}}}}$ 782.66 ± 0.13 0 1−− 0 0 0 (7.58±0.11)×10−23 s
π+
+
π0
+
π
or

π0
+
γ

The quark composition of the
ω
meson can be thought of as a mix between
u

u
,
d

d
and
s

s
states, but it is very nearly a pure symmetric
u

u
-
d

d
state. This can be shown by deconstructing the wave function of the
ω
into its component parts. We see that the
ω
and
ϕ
mesons are mixtures of the SU(3) wave functions as follows.[7]

${\displaystyle \omega =\psi _{8}\sin \theta +\psi _{1}\cos \theta }$,
${\displaystyle \phi =\psi _{8}\cos \theta -\psi _{1}\sin \theta }$,

where

${\displaystyle \theta }$ is the nonet mixing angle,
${\displaystyle \psi _{1}={\frac {u{\overline {u}}+d{\overline {d}}+s{\overline {s}}}{\sqrt {3}}}}$ and
${\displaystyle \psi _{8}={\frac {u{\overline {u}}+d{\overline {d}}-2s{\overline {s}}}{\sqrt {6}}}}$.

The mixing angle at which the components decouple completely can be calculated to be ${\textstyle \arctan {\frac {1}{\sqrt {3}}}\approx 35.3^{\circ }}$, which almost corresponds to the actual value calculated from the masses of 35°. Therefore, the
ω
meson is nearly a pure symmetric
u

u
-
d

d
state.

4. ^ Gell-Mann, M. (March 15, 1961). "The Eightfold Way: A Theory of Strong Interaction Symmetry" (TID-12608). Pasadena, CA: California Inst. of Tech., Synchrotron Laboratory: 24. doi:10.2172/4008239. {{cite journal}}: Cite journal requires |journal= (help)