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Da-Xin Zhang

Publications and source records attributed to Da-Xin Zhang.

41 records · Page 3Linked to original sources
arXiv1996

Weak Radiative Decays of Beauty Baryons

Weak radiative decays of beauty baryons into strange baryons, induced by the electroweak penguin, are estimated by using a quark model approach. Relations between formfactors in the semileptonic and in the weak radiative decays are derived within the heavy quark effective theory. The partial decay widths are found to be of the order of $10^{-15}{\rm MeV}$ for $Λ_b\rightarrowΛγ$ and $Ξ_b\rightarrowΞγ$ and of the oder of $10^{-13}{\rm MeV}$ for $Ω_b\rightarrowΩγ$. The $Ω_b$ radiative decay is thus expected at the sizable branching ratio of approximately $10^{-4}$.

hep-ph↗
arXiv1996

$B_s (B_d) \to γν\bar ν$ }

We study the loop induced rare decays $B_s(B_d)\toγν\barν$ within the standard model. Both constituent quark model and pole model are used and the branching ratios turn out to be of the orders of $10^{-8}$ for $B_s\to γν\bar ν$ and $10^{-9}$ for $B_d \to γν\bar ν$. These processes can be served to determine the decay constants of $B_s$ and $B_d$.

hep-ph↗
arXiv1996

Two-body Cabibbo-suppressed Decays of Charmed Baryons into Vector Mesons and into Photons

The heavy quark effective theory and the factorization approximation are used to treat the Cabibbo-suppressed decays of charmed baryons to vector mesons, $Λ_C\rightarrow p{ρ^0}, pω$, $Ξ_C^{+,0}\rightarrowΣ^{+,0}ϕ, Σ^{+,0}{ρ^0}, Σ^{+,0}ω$ and $Ξ_C^{0}\rightarrowΛϕ, Λρ, Λω$. The input from two recent experimental results on $Λ_C$ decays allows the estimation of the branching ratios for these modes, which turn out to be between $10^{-4}$ and $10^{-3}$. The long distance contribution of these transitions via vector meson dominance to the radiative weak processes $Λ_C\rightarrow pγ$, $Ξ_C\rightarrowΣγ$ and $Ξ_C^0\rightarrowΛγ$ leads to quite small branching ratios, $10^{-6}-10^{-9}$; the larger value holds if a sum rule between the coupling constants of the vector mesons is broken.

hep-ph↗