Eta and eta prime mesons

Eta and eta prime mesons
Composition	η : ≈ ; η′ : ≈ ;
Statistics	Bosonic
Family	Mesons
Interactions	Strong, Weak, Gravitation, Electromagnetic
Symbol	η, η′
Antiparticle	Self
Discovered	Aihud Pevsner et al. (1961)
Types	2
Mass	η : 547.862±0.018 MeV/c2; η′ : 957.78±0.06 MeV/c2
Mean lifetime	η: (5.0±0.3)×10−19 s, η′: (3.2±0.2)×10−21 s
Decays into	η :; γ + γ or ; π0; + π0; + π0; or ; π+; + π0; + π−; ; η′ :; π+; + π−; + η or; (ρ0; + γ) / (π+; + π−; + γ) or; π0; + π0; + γ;
Electric charge	0 e
Spin	0
Isospin	0
Hypercharge	0
Parity	-1
C parity	+1

The eta (η) and eta prime meson (η′) are isosinglet mesons made of a mixture of up, down and strange quarks and their antiquarks. The charmed eta meson (η
_c) and bottom eta meson (η
_b) are similar forms of quarkonium; they have the same spin and parity as the (light) η defined, but are made of charm quarks and bottom quarks respectively. The top quark is too heavy to form a similar meson, due to its very fast decay.

Composition	η : ≈ ${\textstyle \mathrm {\frac {1}{\sqrt {6}}} \left(u{\bar {u}}+d{\bar {d}}-2s{\bar {s}}\right)}$ η′ : ≈ ${\textstyle \mathrm {\frac {1}{\sqrt {3}}} \left(u{\bar {u}}+d{\bar {d}}+s{\bar {s}}\right)}$
Statistics	Bosonic
Family	Mesons
Interactions	Strong, Weak, Gravitation, Electromagnetic
Symbol	η, η′
Antiparticle	Self
Discovered	Aihud Pevsner et al. (1961)
Types	2
Mass	η : 547.862±0.018 MeV/c² η′ : 957.78±0.06 MeV/c²
Mean lifetime	η: (5.0±0.3)×10⁻¹⁹ s, η′: (3.2±0.2)×10⁻²¹ s
Decays into	η : γ + γ or π⁰ + π⁰ + π⁰ or π⁺ + π⁰ + π⁻ η′ : π⁺ + π⁻ + η or (ρ⁰ + γ) / (π⁺ + π⁻ + γ) or π⁰ + π⁰ + γ
Electric charge	0 e
Spin	0
Isospin	0
Hypercharge	0
Parity	-1
C parity	+1