Quantum chromodynamics observed particles make isospin and SU(3) multiplets. The approximate flavor symmetries do have associated gauge bosons, observed particles like the rho and the omega, but these particles are nothing like the gluons and they are not massless. They are emergent gauge bosons in an approximate string description of QCD. The dynamics of the quarks and gluons are controlled by the quantum chromodynamics Lagrangian. The gauge invariant QCD Lagrangian is where formula_1 is the quark field, a dynamical function of spacetime, in the fundamental representation of the SU(3) gauge group, indexed by formula_2; formula_3 is the gauge covariant derivative; the γ
Technicolor (physics) "M", and the coupling of quarks and leptons to the new particles must be suppressed relative to their coupling to the gauge bosons. This is the case with technicolor, so long as the lightest technivector mesons, "ρ" and "a", are heavier than 200–300 GeV. The "S"-parameter is sensitive to all new physics at the TeV scale, while "T" is a measure of weak-isospin breaking effects. The "U"-parameter is generally not useful; most new-physics theories, including technicolor theories, give negligible contributions to it. The "S" and "T"-parameters are determined by global fit to experimental data including "Z"-pole data from LEP at