The γ∗γ∗→ ηc (1S; 2S) transition form factor from quarkonium wave functions

• We discuss γ ∗γ ∗→ ηc(1S) ; ηc (2S) transition form factor for both virtual photons. The general formula is given. We use difierent models for the cc̄ wave function obtained from the solution of the Schrödinger equation for diffierent cc̄ potentials: harmonic oscillator, Cornell, logarithmic, power-law, Coulomb and Buchmüller{Tye. We showed some examples of wave functions in the Light Front representation as well as in the rest frame of cc̄. We compare our results to the BaBar experimental data for ηc(1S), with one real and one virtual photon, and to the values collected by the Particle Data Group for the form factor F(0; 0), decay width τγ γ and decay constant fηc . We also consider the non-relativistic limit for F(0; 0) with the wave function evaluated at the origin R(0).

Ämnesord

NATURVETENSKAP  -- Matematik -- Matematisk analys (hsv//swe)

NATURAL SCIENCES  -- Mathematics -- Mathematical Analysis (hsv//eng)

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