The strong coupling constants, gD(s)DK(0)*, gB(s)BK(0)*, gD(s)*DK, gB(s)*BK, gD(s)*DK1 and gB(s)*BK(1), where K(0)*, K and K(1) are scalar, pseudoscalar, and axial-vector kaon mesons, respectively, are calculated in the framework of three-point QCD sum rules. In particular, the correlation functions of the considered vertices when both B(D) and K(0)*(K)(K(1)) mesons are off shell are evaluated. In the case of K(1), which is either K(1)(1270) or K(1)(1400), the mixing between these two states are also taken into account. A comparison of the obtained result with the existing prediction on g(Ds)*(DK) as the only coupling constant among the considered vertices, previously calculated in the literature, is also made

The tree-level b → clν l based hadronic transitions have been the focus of much attention since recording significant deviations of the experimental data, on the ratios of the branching fractions in τ and e − μ channels of the semileptonic B → D transition, from the SM predictions by the BABAR Collaboration in 2012. It can be of great importance to look whether similar discrepancies take place in the semileptonic baryonic Λ b → Λ c lν l decay channel or not. In this accordance we estimate the decay width as well as the ratios of the branching fractions in τ and e − μ channels of this baryonic transition by calculating the form factors, entering the amplitude of this transition as the main inputs, in the framework of QCD sum rules in full theory. We compare the obtained results with the predictions of other theoretical studies. Our results may be compared with the corresponding future experimental data to look for possible deviations of data from the SM predictions.

Erratum: Properties of D Ã s2 ð2573Þ charmed-strange tensor meson [Phys. Rev. D 88, 036005 (2013)]

In this work the properties of the axial-tensor K2(1820) meson in a hot medium are investigated. The mass and the decay constant of this state are calculated via thermal QCD sum rules considering QCD condensates up to dimension five. Our analysis show that both mass and decay constant stay almost monotonous up to certain temperatures and then they diminish with increasing temperature. The mass and decay constant estimated at zero temperature are in good agreement with the present experimental data and theoretical estimations.

Motivated by the very recent discovery of the strange hidden-charm exotic state $$Z_{cs}(3985)$$ Z cs ( 3985 ) by the BESIII Collaboration, we study the possible interpretation of this exotic state the both at $$T=0$$ T = 0 and $$ T\ne 0 $$ T ≠ 0 . We analytically compute the mass and meson-current coupling constant of this resonance with spin-parity $$ J^{P} = 1^+$$ J P = 1 + at finite temperature approximation up to the sixth order of the thermal operator dimension including non-perturbative contributions. Extracting thermal mass and meson-current coupling constant sum rules, the modifications on properties of the $$Z_{cs}(3985)$$ Z cs ( 3985 ) state in hot medium are determined. As a by-product, the hadronic parameters of the bottom partner of $$Z_{cs}(3985)$$ Z cs ( 3985 ) is estimated as well. The search for temperature effects on the hadronic parameters of the hidden-charm meson $$Z_{cs}(3985)$$ Z cs ( 3985 ) and the bottom partner enable us to understand the phase transitions, chiral symmetry breaking, and the properties of hot-dense matter in QCD. Moreover, the full width of the resonance $$Z_{cs}(3985)$$ Z cs ( 3985 ) is calculated as $$(12.0\pm 0.8)~{\mathrm {MeV}}$$ ( 12.0 ± 0.8 ) MeV using the strong decay in the tetraquark picture. Results for width and mass are in reasonable agreement with existing experimental data and results of other theoretical works. The information obtained about the parameters of the considered states is useful for experimental investigations of exotic mesons.