Isoscalar and isovector kaon form factors from e+e− and τ data

The recent precise measurements of the e+e−→ KS KL and e+e−→ K+K− cross sections and the hadronic spectral function of the τ−→ K−KS ντ decay are used to extract the isoscalar and isovector electromagnetic kaon form factors and their relative phase in a model independent way. The experimental results are compared with a fit based on the vector-meson-dominance model.

Study of the process e+e−→ π+π−π0η at the SND detector

The reaction e+e−→ π+ π−π0η has been studied in the experiment with the SND detector at the VEPP-2000 e+ e− collider. The reaction proceeds via the four intermediate states: ωη, φη, a0ρ, and structureless π+π−π0η state, which may be, for example, ρ(1450) with ρ(1450) → ρ(770)η. The total e+e−→ π+π−π0η cross section and cross section for the four intermediate states have been measured and fitted in the vector meson dominance model.

Rare four leptonic B-mesons decays with a neutrino in final state

We revisit prediction for the four – leptonic decay of charged B - mesons in the Standard Model and provide an updated results for branching ratios and various differential distributions. We have taken into account relative phase between intermediate ρ0(770) – and ω(782) – resonances contributing to the amplitude in the framework Vector Meson Dominance model approach.

f1(1285) → e+e- decay and direct f1 production in e+e- collisions

The width of the f1(1285) → e+e+e- decay is calculated in the vector meson dominance model. The result depends on the relative phase between two coupling constants describing f1 → ρ0γ decay. The width Γ( f1 → e+e+e-) is estimated to be ≃ 0:07 - 0:19 eV. Direct f1 production in e+e+e- collisions is discussed, and the e+e+e- → f1 → a0π → ηππ cross section is calculated. Charge asymmetry in the e+e+e- → ηπ+π- reaction due to interference between e+e+e- → f1 and e+e+e- → ηρ0 amplitudes is studied.

Determination of the magnetic dipole moment of the rho meson using four-pion electroproduction data

We determine the magnetic dipole moment of the rho meson using preliminary data from the BaBar Collaboration for the [Formula: see text] process, in the center of mass energy range from 0.9 to 2.2 GeV. We describe the [Formula: see text] vertex using a vector meson dominance model, including the intermediate resonance contributions relevant at these energies. We find that [Formula: see text] in [Formula: see text] units.

DETERMINATION OF THE MAGNETIC DIPOLE MOMENT OF THE RHO MESON

We determine the magnetic dipole moment of the rho meson using preliminary data from the BaBar Collaboration for the e+e- → π+π-2π0 process, in the center of mass energy range from 0.9 to 2.2 GeV. We describe the γ* → 4π vertex using a vector meson dominance model, including all intermediate resonance contributions. We find that μρ = 2.1 ± 0.5 [e/2mρ].