Guray Erkol

We evaluate the spin-$3/2\to \text{spin}\text{−}1/2$ electromagnetic transitions of the doubly charmed baryons on $2+1$ flavor, $32^3\times 64$ PACS-CS lattices with a pion mass of $156(9)\mathrm{MeV}/c^2$. A relativistic heavy quark action is employed to minimize the associated systematic errors on charm-quark observables. We extract the magnetic dipole, $M1$, and the electric quadrupole, $E2$, transition form factors. In order to make a reliable estimate of the $M1$ form factor, we carry out an analysis by including the effect of excited-state contributions. We find that the $M1$ transition is dominant and light degrees of freedom ($u/d$- or $s$-quark) play the leading role. $E2$ form factors, on the other hand, are found to be negligibly small, which in turn, have a minimal effect on the helicity and transition amplitudes. We predict the decay widths and lifetimes of ${\mathrm{\Xi }}_{cc}^{*+,++}$ and ${\mathrm{\Omega }}_{cc}^{*+}$ based on our results. Finite size effects on these ensembles are expected to be around 1%. Differences in kinematical and dynamical factors with respect to the $N\gamma \to \mathrm{\Delta }$ transition are discussed and compared to nonlattice determinations while keeping possible systematic artifacts in mind. A comparison to ${\mathrm{\Omega }}_c\gamma \to {\mathrm{\Omega }}_c^{*}$ transition and a discussion on systematic errors related to the choice of heavy quark action are also given. Results we present here are particularly suggestive for experimental facilities such as LHCb, PANDA, Belle II, and BESIII to search for further states.

I report on the transition from factors of ${\Omega }_{c\gamma }\to {\Omega }_c^{*}$ and the preliminary results for ${\Xi }_{c\gamma }\to {{\Xi }^{\prime }}_c$ transitions in lattice QCD, which give access to the only decay modes of ${\Omega }_c^{*}$ and ${{\Xi }^{\prime }}_c$ . The decay rates of ${\Omega }_c^{*}$ and ${{\Xi }^{\prime }}_c$ as extracted from lattice QCD are also given.

The electromagnetic form factors of the spin-$3/2$ $\mathrm{\Omega }$ baryons, namely $\mathrm{\Omega }$, ${\mathrm{\Omega }}_c^{*}$, ${\mathrm{\Omega }}_{cc}^{*}$ and ${\mathrm{\Omega }}_{ccc}$, are calculated in full QCD on ${32}^3\times 64$ PACS-CS lattices with a pion mass of 156(9) MeV. The electric charge radii and magnetic moments from the $E0$ and $M1$ multipole form factors are extracted. Results for the electric quadrupole form factors, $E2$, are also given. Quark sector contributions are computed individually for each observable and then combined to obtain the baryon properties. We find that the charm quark contributions are systematically smaller than the strange-quark contributions in the case of the charge radii and magnetic moments. $E2$ moments of the ${\mathrm{\Omega }}_{cc}^{*}$ and ${\mathrm{\Omega }}_{ccc}$ provide a statistically significant data to conclude that their electric charge distributions are deformed to an oblate shape. Properties of the spin-$1/2$ ${\mathrm{\Omega }}_c$ and ${\mathrm{\Omega }}_{cc}$ baryons are also computed and a thorough comparison is given. This complete study gives valuable hints about the heavy-quark dynamics in charmed hadrons.