Phenomenological model for the γ*γ Xiu-Lei Ren, Igor Danilkin, Marc Vanderhaeghen

Motivated by the ongoing analysis by the BESIII Collaboration on the single-tagged e+e−→e+e−ηπ+π− reaction, we present a phenomenological study of the diphoton fusion to ηπ+π−, focusing on the production mechanism of the f1(1285) resonance. Contributions from the f1(1285)→a0(980)±π∓ and f1(1285)→σ/f0(500)η channels are included without introducing free parameters within an effective Lagrangian approach. Assuming the destructive interference between the amplitudes, we predict the invariant mass distributions, angular distributions, and total cross sections of the γ*γ→ηπ+π− process, which will be tested by the forthcoming BESIII measurements.