Speakers
Description
In 2009, the CLAS collaboration reported the first observation of scalar meson photoproduction in the π+π− channel. Because the cross section in this channel is dominated by the vector ρ(770) resonance, the observation of the $f_0(980)$ peak in the mass distribution was not possible. Instead, the resonant S-wave contribution was inferred through subtle interference effects in the moments of the angular distribution.
To further clarify the role of scalar mesons in photon-induced reactions, both careful theoretical modeling and refined experimental techniques are essential. A recent Regge-theory-based study by JPAC marks a significant step forward in modeling, but further developments—such as the proper inclusion of coupled-channel effects—are still needed. On the experimental side, efforts include, among others, addressing the limited phase space coverage of the CLAS detector.
To this end, we introduce a novel strategy to unfold detector distortions in CLAS two-pion photoproduction measurements using a diffusion model. By training the model on simulated events, we enable it to recover the "true" kinematic distributions from reconstructed data, from which moment distributions can then be extracted. Simulations are initially based on pure phase space, but we plan to incorporate the JPAC model, with or without the $f_0(980)$, in the near future.
This approach improves the learning convergence rate—and, desirably, flexibility across different topologies—compared to generative adversarial networks (GANs), and paves the way for extracting moments from real CLAS data.
