arXiv subjects

Kang-Kang Shao

Publications and source records attributed to Kang-Kang Shao.

3 recordsLinked to original sources

arXiv2025

First determination of $V_{cs,cd}$ from inclusive $D$ meson decays

We report the first determination of the Cabibbo-Kobayashi-Maskawa matrix elements $|V_{cs}|$ and $|V_{cd}|$ from a global fit to data from inclusive and sum-of-exclusive charm decays. Simultaneously, the heavy quark expansion parameters are determined, and they are in good agreement with results from the literature, validating the robustness of this work. With the current precision, our determined value for $|V_{cs}|$ is consistent with the world-average value extracted from exclusive charm decay processes, while a tension of approximately $3σ$ is observed for $|V_{cd}|$ when compared to its exclusive world-average counterpart.

hep-ph↗

arXiv2025

Data determination of HQET parameters in inclusive charm decays

This work delves into the phenomenology of electronic inclusive decays of $D$ mesons, encompassing $D^0, D^+, D^+_s\to Xe^{+}ν$. The theoretical formulas for the decay widths and electron energy moments of these decays are presented as expansions with powers of $α_s$ and $Λ_{\rm QCD}/m_c$. Remarkably, the expansion exhibits excellent convergence properties when we choose the 1S mass scheme for charm. The formulas are subsequently fitted to experimental data, and the $D$ meson matrix elements of operators in the heavy quark effective theory are hence determined by data for the first time, including \begin{align} μ^2_π(D^{0,+}) &= (0.09\pm 0.05) \mathrm{GeV}^2, \qquad \qquad μ^2_π(D^{+}_s) = (0.11\pm 0.05) \mathrm{GeV}^2, \nonumber \\ μ^2_G(D^{0,+}) &= (0.32\pm 0.02) \mathrm{GeV}^2, \qquad \qquad μ^2_G(D^{+}_s) = (0.43\pm 0.02) \mathrm{GeV}^2, \nonumber \\ ρ_D^3(D^{0,+}) &= (-0.003\pm 0.002) \mathrm{GeV}^3, \qquad\ ρ_D^3(D^{+}_s) = (-0.004\pm 0.002) \mathrm{GeV}^3, \nonumber \\ ρ_{LS}^3(D^{0,+}) &= (0.004\pm 0.002) \mathrm{GeV}^3, \qquad \ \ \ ρ_{LS}^3(D^{+}_s) = (0.005\pm 0.002) \mathrm{GeV}^3 . \nonumber \end{align} These determined parameters will play a crucial role as inputs in various physical quantities, including $D$ meson lifetimes.

hep-ph↗

arXiv2022

Inclusive weak-annihilation decays and lifetimes of beauty-charmed baryons

Imbalanced beauty-charmed baryons $ Ξ_{bc}^{+,0} $ are of great significance to the development of heavy flavor physics. In this work, we study the inclusive weak-annihilation decays of $Ξ_{bc}^{+,0}$ and their contributions to the $Ξ_{bc}^{+,0}$ lifetimes. For the calculation of the inclusive $Ξ_{bc}^{+,0}\to X_{cs}$ decay width where $X_{cs}$ stands for the sum of the final states with charm number +1 and strange number -1, we work in the heavy diquark effective theory which provides us with a convenient technical tool to construct the operator product expansion. The $Ξ_{bc}^{+,0}$ is considered to be a superposition of two states with one containing a spin-0 $bc$ diquark and the other one containing a spin-1 $bc$ diquark. It is found that both the $Ξ_{bc}^{+,0}$ lifetimes and the $Ξ_{bc}^{+,0}\to X_{cs}$ branching ratios are very sensitive to the $bc$ spin in $Ξ_{bc}^{+,0}$. The $Ξ_{bc}^{+,0}\to X_{cd}$ results are also presented. As $Ξ_{bc}^+$ has a longer lifetime than $Ξ_{bc}^{0}$ and bigger branching ratios of similar decay channels, the exclusive decays $Ξ_{bc}^+\to D^{(*)+}Λ$, $Ξ_{bc}^+\to Λ_c^+\bar{K}^{(*)0}$, $Ξ_{bc}^+\to D^{(*)+}K^-p$, and $Ξ_{bc}^+\to D^{0}\bar{K}^{(*)0}p$ are more promising for experimental searches of $Ξ_{bc}^{+,0}$ at the LHC comparing with exclusive decay $Ξ_{b c} ^{0} \to D^0pK^-$.

hep-ph↗