Radius of theρmeson determined from its decay constant

Abstract

We present a unified model describing electroweak properties of the π and ρ mesons. Using a general method of relativistic parametrization of matrix elements of local operators, adjusted for the nondiagonal in total angular momentum case, we calculate the ρ-meson lepton-decay constant fρ using the same parameters of free constituent quarks that have ensured exclusively good results for the π meson previously. The only free parameter, characterising quark interactions, which include additional spin-spin contribution and hence differ from the π-meson case, is fixed by matching the decay constant to its experimental value. The mean square charge radius is calculated, r 2 ρ = (0.56 ± 0.04) fm 2 . This result verifies, for the ρ-meson case, the conjecture of equality between electromagnetic and strong radii of hadrons tested previously for proton, π and K mesons.

Strong couplings and form factors of charmed mesons in holographic QCD

“…We are interested in describing strong couplings involving charmed mesons D and D * , strange mesons K and K * as well as light mesons π and ρ. Then in (65) and (66) we select only a = (1, .., 7) and a = (9, .., 12) for the pseudoscalar mesons π a , whereas for the vector mesons we pick a = (1.., 7), a = (9, .., 12) and a = (8, 15). The other states are taken to zero.…”

Electroweak properties ofρ-meson in the instant form of relativistic quantum mechanics

“…In this work the model parameters are fixed from the calculations of electroweak properties of pion [14] and from description of the lepton decay constant of ρ-meson [15]. So, our calculations of the magnetic moment and the charge radius are performed without fitting parameters and give the good agreement with experimental data.…”

“…For the calculation of the ρ-meson lepton decay constant we used the method of construction of current matrix element which is nondiagonal with respect to the total angular momentum [15]. Final expression for f ρ in approximation of four-fermion interaction in our approach has form [15]:…”

Poincaré-invariant constituent quark model for light mesons: capabilities and constraints

“…The method of the parameterization of the current matrix elements has been generalized in the paper [15] to the case of the nondiagonal in the total angular momentum matrix elements. In particular the expression for the lepton decay constant of the ρ-meson was obtained in the 4-fermion approximation:…”

“…So, the wave functions u(k) (15) resulting in the resonance behavior of the pion form factor for timelike transferred momenta must have a pole at the point k s :…”