Strong Ds∗Dsη(′)D^{*}_sD_{s}\eta^{(\prime)} and Bs∗Bsη(′)B^{*}_sB_{s}\eta^{(\prime)} vertices from QCD light-cone sum rules

The strong $D^{*}_sD_{s}\eta^{(\prime)}$ and $B^{*}_sB_{s}\eta^{(\prime)}$ vertices are studied and the relevant couplings are calculated in the context of the light-cone QCD sum rule method with twist-4 accuracy by including the next-to-leading order corrections. In the analysis, both the quark and gluon components of the $\eta$ and $\eta^{\prime}$ mesons and the axial anomaly corrected higher twist distributions are included.Comment: 15 Pages and 6 Figure

Charmed partner of the exotic X(5568)X(5568) state and its properties

The mass, decay constant and width of a hypothetical charmed partner $X_c$ of the newly observed exotic $X_b(5568)$ state are calculated using a technique of QCD sum rule method. The $X_c=[su][\overline{c}\overline{d}]$ state with $J^{P}=0^{+}$ is described employing two types of the diquark-antidiquark interpolating currents. The evaluation of the mass $m_{X_c}$ and decay constant $f_{X_c}$ is carried out utilizing the two-point sum rule method by including vacuum condensates up to eight dimensions. The widths of the decay channels $X_c \to D_s^{-} \pi^{+}$ and $X_c \to D^{0} K^{0}$ are also found. To this end, the strong couplings $g_{X_{c}D_{s}\pi}$ and $g_{X_{c}D K}$ are computed by means of QCD sum rules on the light-cone and soft-meson approximation.Comment: 7 Pages, 2 Figures and 3 Table

Strong Zc+(3900)→J/ψπ+;ηcρ+Z_c^{+}(3900)\rightarrow J/\psi \pi^{+}; \eta_{c} \rho^{+} decays in QCD

The widths of the strong decays $Z_c^{+}(3900)\to J/\psi \pi^{+}$ and $Z_c^{+}(3900)\to \eta_{c} \rho^{+}$ are calculated. To this end, the mass and decay constant of the exotic $Z_c^{+}(3900)$ state are computed by means of a two-point sum rule. The obtained results are then used to calculate the strong couplings $g_{Z_{c}J/\psi \pi }$ and $g_{Z_{c}\eta_{c} \rho }$ employing QCD sum rules on the light-cone supplied by a technique of the soft-meson approximation. We compare our predictions on the mass and decay widths with available experimental data and other theoretical results.Comment: 11 Pages, 3 Figures and 2 Tables; To be published by Physical Review

Width of the exotic Xb(5568)X_b(5568) state through its strong decay to Bs0π+B_s^{0} \pi^{+}

The width of the newly observed exotic state $X_b(5568)$ is calculated via its dominant strong decay to $$ using the QCD sum rule method on the light-cone in conjunction with the soft-meson approximation. To this end, the vertex $X_{b}B_{s}\pi$ is studied and the strong coupling $g_{X_{b}B_{s}\pi}$ is computed employing for $X_b(5568)$ state the interpolating diquark-antidiquark current of the $[su][\overline{b}\overline{d}]$ type. The obtained prediction for the decay width of $X_b(5568)$ is confronted and a nice agreement found with the experimental data of the D0 Collaboration.Comment: 6 Pages, 2 Figures and 1 Tabl

Mass and decay constant of the newly observed exotic X(5568)X(5568) state

The mass and decay constant of the $X(5568)$ state newly observed by D0 Collaboration are computed within the two-point sum rule method using the diquark-antidiquark interpolating current. In calculations, the vacuum condensates up to eight dimensions are taken into account. The obtained result for the mass of the $X(5568)$ state is in a nice agreement with the experimental data.Comment: 5 Pages, 2 Figures and 1 Table; To be published in Phys. Rev. D. arXiv admin note: text overlap with arXiv:1601.0384

Application of the QCD light cone sum rule to tetraquarks: the strong vertices XbXbρX_bX_b\rho and XcXcρX_cX_c\rho

The full version of QCD light-cone sum rule method is applied to tetraquarks containing a single heavy $b$ or $c$ quark. To this end, investigations of the strong vertices $X_{b}X_{b}\rho$ and $X_{c}X_{c}\rho$ are performed, where $X_b=[su][\bar b\bar d]$ and $X_c=[su][\bar c\bar d]$ are the exotic states built of four quarks of different flavors. The strong coupling constants $G_{X_{b}X_{b}\rho}$ and $G_{X_{c}X_{c}\rho}$ corresponding to these vertices are found using the $\rho$-meson leading and higher-twist distribution amplitudes. In the calculations $X_{b}$ and $X_{c}$ are treated as scalar bound states of a diquark and antidiquark.Comment: 10 Pages, 5 Figures and 1 Tabl

Exploring X(5568)X(5568) as a meson molecule

The parameters, i.e. the mass and current coupling of the exotic $X(5568)$ state observed by the D0 Collaboration as well as the decay width of the process $X \to B_s^{0}\pi^{+}$ are explored using $B\bar{K}$ molecule assumption on its structure. Employed computational methods include QCD two-point and light-cone sum rules, latter being considered in the soft-meson approximation. The obtained results are compared with the data of the D0 Collaboration as well as with the predictions of the diquark-antidiquark model. This comparison strengthens a diquark-antidiquark picture for the $X(5568)$ state rather than a meson molecule structure.Comment: 7 Pages, 2 Figures and 1 Tabl

Investigation of the semileptonic transition of the BB into the orbitally excited charmed tensor meson

The transition form factors of the semileptonic $B \rightarrow D_2^*(2460)\ell\bar{\nu}\,\,\,\,(\ell=\tau,\mu,e)$ decay channel are calculated within the framework of the three-point QCD sum rules. The fit functions of the form factors are then used to estimate the total decay width and branching ratio of this transition. The order of branching ratio shows that this channel can be detected at LHCb.Comment: 15 Pages, 4 Figures and 5 Table