Programme

O.13 -- Oral, VCTP-48

Date: Thursday, 3 August 2023

Time: 11:05 - 11:30

Study of radiative decays $D^*_{(s)} \to D_{(s)} \gamma$

Chien-Thang Tran (1), Mikhail A. Ivanov (2), Pietro Santorelli (3), Quang-Chau Vo (4)

(1) Ho Chi Minh City University of Technology and Education; (2) Joint Institute for Nuclear Research, Dubna, Russia; (3) University of Naples Federico II & INFN, Naples, Italia; (4) Ho Chi Minh City University of Science

Radiative decays $D^*_{(s)}\to D_{(s)}\gamma$ are revisited in light of new experimental data from \emph{BABAR} and BESIII collaborations. The radiative couplings $g_{D^*D\gamma}$ encoding nonperturbative QCD effects are calculated in the framework of the covariant confined quark model developed by us. We compare our results with other theoretical studies and experimental data. The couplings (in $\textrm{GeV}^{-1}$) $g_{D^{*+}D^+\gamma} = -0.45(9)$ and $g_{D^{*0}D^0\gamma} = 1.72(34)$ calculated in our model agree with the experimental data $g_{D^{*+}D^+\gamma}=-0.47(7)$ and $g_{D^{*0}D^0\gamma}=1.77(16)$. The most interesting case is the decay $D^*_s\to D_s\gamma$, for which recent predictions of lattice QCD ($\Gamma(D^*_s\to D_s\gamma)=0.066(26)\,\textrm{keV}$) and light-cone sum rules at next-to-leading order ($\Gamma(D^*_s\to D_s\gamma)=2.36^{+1.49}_{-1.41}\,\textrm{keV}$) disagree. Our calculation yields $\Gamma(D^*_s\to D_s\gamma)=0.55(22)\,\textrm{keV}$, which falls somehow between the two mentioned results, but larger than those predicted in other studies using quark models or QCD sum rules.

Presenter: Tran Chien-Thang