Programme

P.1 -- Posters, VCTP-51

Date: Tuesday, 4 August 2026

Time: 09:30 - 10:30

Bayesian Parameter Estimation and Uncertainty Quantification in Radiative Charmonium Transitions

Aidos Issadykov (1,2), Mikhail A. Ivanov (1), Dang-Khoa N. Nguyen (3), Chien-Thang Tran (3), Akmaral Tyulemissova (1,2), Zhomart Tyulemissov (1,2,4)

(1) Bogoliubov Laboratory of Theoretical Physics, JINR, Joliot-Curie 6, 141980 Dubna, Russia; (2) The Institute of Nuclear Physics, Agency of the Republic of Kazakhstan for Atomic Energy, Almaty, 050032 Kazakhstan; (3) Department of Physics, Ho Chi Minh City University of Technology and Education, Vo Van Ngan 1, 700000 Ho Chi Minh City, Vietnam; (4) Al-Farabi Kazakh National University, Almaty, 050040 Kazakhstan

We study radiative charmonium transitions within the Covariant Confined Quark Model (CCQM). Our predictions for the branching fractions agree well with experimental data. An important part of our analysis is the fitting process for the model free parameters and theoretical error estimation. In this poster, we describe the statistical determination of the model parameters entering the decay amplitudes. In particular, we extract two key parameters of the model: the charm quark mass ($m_c$) and the hadron size parameter ($\rho$). The parameter estimation is performed using Bayesian inference with the Nested Sampling algorithm, while uncertainties associated with particle masses and widths are incorporated through nuisance parameters. The theoretical predictions are fitted to the currently available experimental branching fractions of $J/\psi \to \eta_c \gamma$, $\chi_{c0} \to J/\psi \gamma$, and $\psi(2S) \to \chi_{c0} \gamma$. The resulting Bayesian credible intervals are compared with confidence intervals obtained from a profile likelihood analysis, showing good agreement between the two approaches. The posterior parameter samples are propagated through the model using Monte Carlo techniques to predict branching fractions for additional channels, including $h_c \to \eta_c \gamma$ and $\chi_{c1,c2} \to J/\psi \gamma$. We further analyze the relative contributions of different sources of uncertainty to the final predictions. The obtained results indicate that the CCQM can provide a consistent description of radiative charmonium decays while allowing a systematic treatment of theoretical uncertainties.

Presenter: Nguyen Nguyen Dang Khoa