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Register a new userAnalysis of the strong vertexes of $Sigma_c^{*} ND$ and $Sigma_b^{*}NB$ in QCD sum rules
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In this article, we analyze the strong vertexes $Sigma_{c}^{*}ND$ and $Sigma_{b}^{*}NB$ using the three-point QCD sum rules under the Dirac structure of $q!!!/p!!!/gamma_{mu}$. We perform our analysis by considering the contributions of the perturbative part and the condensate terms of $<overline{q}q>$ and $<frac{alpha_{s}}{pi}GG>$. After the form factors are calculated, they are then fitted into analytical functions which are used to get the strong coupling constants for these two vertexes. The final results are $g_{Sigma_{c}^{*}ND}=7.19^{+8.49}_{-3.11}pm1.76$ and $g_{Sigma_{b}^{*}NB}=10.54^{+15.59}_{-5.23}pm1.82$.
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In this article, we study the strong interaction of the vertexes $Sigma_bNB$ and $Sigma_c ND$ using the three-point QCD sum rules under two different dirac structures. Considering the contributions of the vacuum condensates up to dimension $5$ in the operation product expansion, the form factors of these vertexes are calculated. Then, we fit the form factors into analytical functions and extrapolate them into time-like regions, which giving the coupling constant. Our analysis indicates that the coupling constant for these two vertexes are $G_{Sigma_bNB}=0.43pm0.01GeV^{-1}$ and $G_{Sigma_cND}=3.76pm0.05GeV^{-1}$.
The strong coupling constant is an important parameter which can help us to understand the strong decay behaviors of baryons. In our previous work, we have analyzed strong vertices $Sigma_{c}^{*}ND$, $Sigma_{b}^{*}NB$, $Sigma_{c}ND$, $Sigma_{b}NB$ in QCD sum rules. Following these work, we further analyze the strong vertices $Sigma_{c}ND^{*}$ and $Sigma_{b}NB^{*}$ using the three-point QCD sum rules under Dirac structures $q!!!/p!!!/gamma_{alpha}$ and $q!!!/p!!!/p_{alpha}$. In this work, we first calculate strong form factors considering contributions of the perturbative part and the condensate terms $langleoverline{q}qrangle$, $langlefrac{alpha_{s}}{pi}GGrangle$ and $langleoverline{q}g_{s}sigma Gqrangle$. Then, these form factors are used to fit into analytical functions. According to these functions, we finally determine the values of the strong coupling constants for these two vertices $Sigma_{c}ND^{*}$ and $Sigma_{b}NB^{*}$.
In this article, the tensor-vector-pseudoscalar type of vertex is analyzed with the QCD sum rules and the local-QCD sum rules. Correspondingly, the hadronic coupling constants of D2*(2460), Ds2*(2573), B2*(5747) and Bs2*(5840), and their decay widths are calculated. The results indicate that the QCD sum rules and the local-QCD sum rules give the consistent descriptions. Finally, the full widths of these 4 tensor mesons are discussed in detail.
We study $bar{Q}Qbar{q}q$ and $bar{Q}qQbar{q}$ molecular states as mixed states in QCD sum rules. By calculating the two-point correlation functions of pure states of their corresponding currents, we review the mass and coupling constant predictions of $J^{PC}=1^{++}$, $1^{--}$, $1^{-+}$ molecular states. By calculating the two-point mixed correlation functions of $bar{Q}Qbar{q}q$ and $bar{Q}qQbar{q}$ molecular currents, and we estimate the mass and coupling constants of the corresponding ``physical state that couples to both $bar{Q}Qbar{q}q$ and $bar{Q}qQbar{q}$ currents. Our results suggest that $1^{++}$ states are more likely mixing from $bar{Q}Qbar{q}q$ and $bar{Q}qQbar{q}$ components, while for $1^{--}$ and $1^{-+}$ states, there is less mixing between $bar{Q}Qbar{q}q$ and $bar{Q}qQbar{q}$. Our results suggest the $Y$ series of states have more complicated components.
In the framework of three-point QCD sum rules, the form factors for the semileptonic decays of B_c^+ -> B_s(B_s^*) l u are calculated with account for the Coulomb-like alpha_s/v-corrections in the heavy quarkonium. The generalized relations due to the spin symmetry of HQET/NRQCD for the form factors are derived at the recoil momentum close to zero. The nonleptonic decays are studied using the assumption on the factorization. The B_c meson lifetime is estimated by summing up the dominating exclusive modes in the c -> s transition combining the current calculations with the previous analysis of b -> c decays in the sum rules of QCD and NRQCD.
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