as a wide array of subatomic particles (hover mouse for name). Summary table Because this table was initially derived from published results and many of those results were preliminary, as many as 64 of the mesons in the following table may not exist or have the wrong mass or quantum numbers. Mesons named with the letter "f" are scalar mesons (as opposed to a pseudo-scalar meson), and mesons named with the letter "a" are axial-vector mesons (as opposed to an ordinary vector meson) a.k.a. an isoscalar vector meson, while the letters "b" and "h" refer to axial-vector mesons with positive parity, negative C-parity, and quantum numbers IG of 1+ and 0− respectively. The, "f", "a", "b" and "h" mesons are not listed in the tables below and their internal structure and quark content is a matter of ongoing investigation. The particle described in the table above as f0(500) has historically been known by two other names: f0(600) and σ (sigma). A complete set of meson naming conventions is set forth in a 2017 review article for the Particle Data Group which also contains a table mapping pre-2016 common names to the new Particle Data Group standard naming conventions for XYZ mesons. Meson properties The following lists details for all known and predicted pseudoscalar (JP = 0−) and vector (JP = 1−) mesons. The properties and quark content of the particles are tabulated below; for the corresponding antiparticles, simply change quarks into antiquarks (and vice versa) and flip the sign of Q, B, S, C, and B′. Particles with † next to their names have been predicted by the standard model but not yet observed. Values in have not been firmly established by experiments, but are predicted by the quark model and are consistent with the measurements. Pseudoscalar mesons [a] Makeup inexact due to non-zero quark masses. [b] PDG reports the resonance width (Γ). Here the conversion τ = is given instead. [c] Strong eigenstate. No definite lifetime (see kaon notes below) [d] The mass of the and are given as that of the . However, it is known that a difference between the masses of the and on the order of exists. [e] Weak eigenstate. Makeup is missing small CP–violating term (see notes on neutral kaons below). Vector mesons [f] PDG reports the resonance width (Γ). Here the conversion τ = is given instead. [g] The exact value depends on