Measurements of $\pi^{0}\pi^{0}$ production and form factors for $f_{0}(980)$ and $f_{2}(1270)$ in single-tag two-photon process

TL;DR

This paper presents detailed measurements of $$ production cross sections and transition form factors for $f_0(980)$ and $f_2(1270)$ mesons in single-tag two-photon collisions, providing new experimental data up to high $Q^2$ values.

Contribution

First measurement of transition form factors for $f_0(980)$ and $f_2(1270)$ with helicity components in two-photon processes, extending understanding of meson structure.

Findings

Transition form factors measured for the first time.

Results compared with theoretical models, showing agreement or discrepancies.

Data covers $Q^2$ up to 30 GeV$^2$ in a broad kinematic range.

Abstract

We report a measurement of differential cross section of $\pi^{0}$ pair production in single-tag two-photon collisions. These results are obtained with 759$fb^{-1}$ of the data collected with the Belle detector at the KEKB asymmetric energy $e^{+}e^{-}$ collider. The cross section is measured for $Q^{2}$ up to 30 GeV$^{2}$, where $Q^{2}$ is the negative of the invariant mass squared of the tagged virtual photon, in the kinematic range 0.5 GeV < $W$ < 2.1 GeV and |cos$\theta^{*}$| < 1.0 for the total energy and pion scattering angle, respectively. The transition form factor of the $f_{0}(980)$ and that of the $f_{2}(1270)$ with the helicity-0,-1, and -2 components separately are measured for the first time and are compared with theoretical calculations.