No Arabic abstract
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, 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 $G_{Sigma_cND}=3.76pm0.05GeV^{-1}$.
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.
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 $g_{Sigma_{b}^{*}NB}=10.54^{+15.59}_{-5.23}pm1.82$.
The form factors and the coupling constant of the $B_s B^* K $ and $B_s B K^*$ vertices are calculated using the QCD sum rules method. Three point correlation functions are computed considering both the heavy and light mesons off-shell in each vertex, from which, after an extrapolation of the QCDSR results at the pole of the off-shell mesons, we obtain the coupling constant of the vertex. The form factors obtained have different behaviors but their simultaneous extrapolation reach the same value of the coupling constant $g_{B_s B^* K}=8.41 pm 1.23 $ and $g_{B_s BK^*}=3.3 pm 0.5$. We compare our result with other theoretical estimates and compute the uncertainties of the method.
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.