arXiv subjects
Publications and source records attributed to Y. Sarac.
Using the most general form of the interpolating currents, the coupling constants $g_{Σ_bΣ_bπ}$ and $g_{Σ_cΣ_cπ}$ are calculated within the light cone QCD sum rules approach. It is found that $g_{{Σ_{c}Σ_{c}π}}=-8.0\pm1.7$ and $g_{{Σ_{b}Σ_{b}π}}=-11.0\pm2.1$.
For the heavy baryons $Ξ_c$ and $Ξ_b$ the coupling constants $g_{Ξ_cΞ_cπ}$ and $g_{Ξ_bΞ_bπ}$ are calculated in the framework of light cone QCD sum rules. The most general form of the interpolating field of $Ξ_Q$ is used in the calculation.
The tree level semileptonic $Λ_{b}\to plν$ and $Λ_{c}\to nlν$ transitions are investigated using the light cone QCD sum rules approach in full theory. The spin--1/2, $Λ_{Q}$ baryon with $Q=b$ or $c$, is considered by the most general form of its interpolating current. The time ordering product of the initial and transition currents is expanded in terms of the nucleon distribution amplitudes with different twists. Considering two sets of independent input parameters entering to the nucleon wave functions, namely, QCD sum rules and Lattice QCD parameters, the related form factors and their heavy quark effective theory limits are calculated and compared with the existing predictions of other approaches. It is shown that our results satisfy the heavy quark symmetry relations for lattice input parameters and b case exactly and the maximum violation is for charm case and QCD sum rules input parameters. The obtained form factors are used to compute the transition rates both in full theory and heavy quark effective theory. A comparison of the results on decay rate of $Λ_{b}\to plν$ with those predicted by other phenomenological methods or the same method in heavy quark effective theory with different interpolating current and distribution amplitudes of the $Λ_{b}$ is also presented.
Using the most general form of the interpolating current of the heavy spin 1/2, $Σ_{b}$ baryon and distribution amplitudes of the nucleon, the transition form factors of the semileptonic $Σ_{b}\to Nlν$ decay are calculated in the framework of light cone QCD sum rules. It is obtained that the form factors satisfy the heavy quark effective theory relations. The obtained results for the related form factors are used to estimate the decay rate of this transition.
We investigate f_0-sigma mixing in the framework of light cone QCD sum rules and by employing the experimental results about the decay widths and the masses of these scalar mesons we estimate the scalar mixing angle by using sigma meson data and f_0 meson data. The two values we thus obtain of the scalar mixing angle are not entirely consistent with each other, possibly indicating that the structure of these mesons cannot be simple quark-antiquark states.