Omega meson

Summary

Omega meson
Composition
StatisticsBosonic
FamilyMesons
InteractionsStrong, weak, electromagnetic, gravity
Symbol
ω
AntiparticleSelf
TheorizedYoichiro Nambu[1] (1957)
DiscoveredLawrence Berkeley National Laboratory (1961)[2][3]
Types1
Mass782.66±0.13 MeV/c2
Mean lifetime(7.58±0.11)×10−23 s
Decays into
π+
+
π0
+
π
or
π0
+
γ
Electric charge0 e
Spin1
Isospin0
Hypercharge0
Parity−1
C parity−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 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]

,
,

where

is the nonet mixing angle,
and
.

The mixing angle at which the components decouple completely can be calculated to be , 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.

See also

References

  1. ^ Nambu, Yoichiro (April 25, 1957). "Possible Existence of a Heavy Neutral Meson". Physical Review. 106 (6): 1366f. doi:10.1103/PhysRev.106.1366.
  2. ^ Maglić, B. C.; Alvarez, L. W.; Rosenfeld, A. H.; Stevenson, M. L. (August 14, 1961). "Evidence for a T=0 three-pion resonance". Physical Review Letters. 7 (5): 178–182. doi:10.1103/physrevlett.7.178.
  3. ^ Maglich, B. (1976). "Discovery of omega meson-first neutral vector meson: one researcher's personal account - Discovery story". Advanced Experimental Physics. 5: 79–105.
  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)
  5. ^ Ne'eman, Y. (August 1961). "Derivation of Strong Interactions from a Gauge Invariance". Nuclear Physics. Amsterdam: North-Ho lland Publishing Co. 26 (2): 222–229. Bibcode:1961NucPh..26..222N. doi:10.1016/0029-5582(61)90134-1.
  6. ^ a b Zyla, P. A. (2021) [2020]. "Particle listing - ω(782)" (PDF). Particle Data Group. Retrieved June 9, 2021.
  7. ^ Amsler, C.; DeGrand, T.; Krusche, B. (August 2019). "15. Quark Model" (PDF). Particle Data Group. Retrieved 9 June 2021.