The magnetic and quadrupole moments of the vector and axial-vector mesons containing heavy quark are estimated within the light cone sum rules method. Our predictions on magnetic moments for the vector mesons are compared with the results obtained by other approaches.
The form factors of the $Lambda_{b} to N^ast ell^+ ell^-$ decay are calculated in the framework of the light cone QCD sum rules. In the calculations the contribution of the negative parity $Lambda_b^ast$ baryon is eliminated by constructing the sum r
ules for different Lorentz structures. Furthermore the branching ratio of the semileptonic $Lambda_b to N^ast ell^+ ell^-$ decay is calculated. The numerical study for the branching ratio of the $Lambda_{b} to N^ast ell^+ ell^-$ decay indicates that it is quite large and could be measurable at future planned experiments to be conducted at LHCb.
The transition form factors of the radiative decays of the heavy tensor mesons to heavy pseudoscalar and heavy vector mesons are calculated in the framework of the light cone QCD sum rules method at the point $Q^2=0$. Using the obtained values of the
transition form factors at the point $Q^2=0$ the corresponding decay widths are estimated. The results show that the radiative decays of the heavy--light tensor mesons can be measurable in the future planned experiments at LHCb.
Form factors of the rare $Lambda_{b}(Lambda_{b}^*)to Nell^{+}ell^{-}$ decays are calculated in the framework of the light cone QCD sum rules by taking into account of the contributions from the negative parity baryons. Using the obtained results on t
he form factors, the branching ratios of the considered decays are estimated. The numerical survey for the branching ratios of the $Lambda_b rar Nell^+ell^- $ and $Lambda_b^ast rar Nell^+ell^- $ decays indicate that these transitions could be measurable in LHCb in near future. Comparison of our predictions on the form factors and branching ratios with those existing in the literature is also performed.
The transition magnetic moments between negative parity, spin-1/2 heavy baryons are studied in framework of the light cone QCD sum rules. By constructing the sum rules for different Lorentz structures, the unwanted contributions coming from negative
(positive) to positive (negative) parity transitions are removed. It is found that the magnetic moments between neutral negative parity heavy $Xi_Q^{prime 0}$ and $Xi_Q^0$ baryons are very small. Magnetic moments of the $Sigma_Q to Lambda_Q$ and $ Xi_Q^{prime pm} to Xi_Q^pm$ transitions are quite large and can be measured in further experiments.
The magnetic moments of the negative parity, spin-1/2 baryons containing single heavy quark are calculated. The pollution that occur from the transitions between positive and negative parity baryons are removed by constructing the sum rules from different Lorentz structures.
The magnetic moments of heavy sextet $J^P = {1over 2}^+$ baryons are calculated in framework of the light cone QCD sum rules method. Linearly independent relations among the magnetic moments of these baryons are obtained. The results for the magnetic
moments of heavy baryons obtained in this work are compared with the predictions of the other approaches.
If the $X(3872)$ is described by the picture as a mixture of the charmonium and molecular $D^{ast} D$ states; $Y(3940)$ as a mixture of the $chi_{c0}$ and $D^ast D^ast$ states; and $X(4260)$ as a mixture of the tetra-quark and charmonium sates, their
orthogonal combinations should also exist. We estimate the mass and residues of the states within the QCD sum rules method. We find that the mass splitting among $X$, $Y$ and their orthogonal states is at most $200MeV$. Experimental search of these new states can play critical role for establishing the nature of the new charmonium states.
The magnetic moments of the low lying, negative parity, spin-3/2 baryons are calculated within the light cone QCD sum rules method. The contributions coming from the positive parity, spin-3/2 baryons, as well as from the positive and negative parity
spin-1/2 baryons are eliminated by constructing combinations of various invariant amplitudes corresponding to the coefficients of the different Lorentz structures.
The magnetic dipole G_M(Q^2), electric quadrupole G_E(Q^2), and Coulomb quadrupole G_C(Q^2) form factors, describing the spin-3/2 to spin-1/2 electromagnetic transitions, are investigated within the light cone QCD sum rules. The Q^2 dependence of the
se form factors, as well as ratios of electric quadrupole and Coulomb quadrupole form factors to the magnetic dipole form factors are studied. We also compare our results on the magnetic dipole form factor with the prediction of the covariant spectator quark model.
