arXiv subjects
Publications and source records attributed to T. M. Aliev.
Using the QCD sum rules method, we estimate the mass and residues of the first radial excitations of octet baryons. The contributions coming from the ground state baryons are eliminated by constructing the linear combinations of the sum rules corresponding to different Lorentz structures. Our predictions of the masses of the first radial excitations of octet baryons are in good agreement with the data.
The strong coupling constants of the $π$ and $K$ mesons with negative parity octet baryons are estimated within the light cone QCD sum rules. It is observed that all strong coupling constants, similar to the case for the positive parity baryons, can be described in terms of three invariant functions, where two of them correspond to the well known $F$ and $D$ couplings in the $SU(3)_f$ symmetry, and the third function describes the $SU(3)_f$ symmetry violating effects. We compare our predictions on the strong coupling constants of pseudoscalar mesons of negative parity baryons with those corresponding to the strong coupling constants for the positive parity baryons.
The magnetic moments of the recently observed resonance $X_b(5568)$ by DO Collaboration and its partner with charm quark are calculated in the framework of the light cone QCD sum rules, by assuming that these resonances are represented as tetra--quark states with quantum numbers $J^{PC}=1^{+\pm}$. The magnetic moment can play critical role in determination of the quantum numbers, as well as giving useful information about the inner structure of these mesons.
We estimate strong coupling constant between the negative parity nucleons with $π$ meson within the light cone QCD sum rules. A method for eliminating the unwanted contributions coming from the nucleon--nucleon and nucleon--negative parity nucleon transition is presented. It is observed that the value strong coupling constant of the negative parity nucleon $N^\ast N^\ast π$ transition is considerably different from the one predicted by the 3--point QCD sum rules, but is quite close to the coupling constant of the positive parity $N N π$ transition.
The transition form factors responsible for the radiative $Σ_Q \to Λ_Q γ$ and $Ξ_Q^\prime \to Ξγ$ decays of the negative parity baryons are examined within light cone QCD sum rules. The decay widths of the radiative transitions are calculated using the obtained results of the form factors.
The light cone sum rules method is used in studying the radiative decays $Σ_Q \to Λ_Q γ$ and $Ξ^\prime_Q \to Ξ_Q γ$. Firstly, the sum rules for the form factor $F_2(Q^2=0)$ responsible for these transitions is constructed. Using this result the decay widths of the above--mentioned decays are calculated and analyzed. A comparison of our predictions on the decay widths of considered transitions with the predictions of the other approaches is presented.
Strong decay constants of the heavy tensor to heavy pseudoscalar (vector) and light pseudoscalar mesons are estimated within the light cone QCD sum rules. It is obtained that the values of these coupling constants are very strongly dependent on the choice of the Lorentz structure. Moreover, using these strong coupling constants the corresponding decay widths are calculated.
The $Σ$--$Λ$ mixing angle is calculated in framework of the QCD sum rules. We find that our prediction for the mixing angle is $(1.00\pm 0.15)^0$ which is in good agreement with the quark model prediction, and approximately two times larger than the recent lattice QCD calculations.
The magnetic dipole moments of the ${\cal D}_2$, and ${\cal D}_{S_2}$, ${\cal B}_2$, and ${\cal B}_{S_2}$ heavy tensor mesons are estimated in framework of the light cone QCD sum rules. It is observed that the magnetic dipole moments for the charged mesons are larger than that of its neutral counterpart. It is found that the $SU(3)$ flavor symmetry violation is about 10\% in both $b$ and $c$ sectors.
The magnetic moment of the $Λ\to Σ^0$ transition between negative parity, baryons is calculated in framework of the QCD sum rules approach, using the general form of the interpolating currents. The pollution arising from the positive--to--positive, and positive to negative parity baryons are eliminated by constructing the sum rules for different Lorentz structures. Nonzero value of the considered magnetic moment can be attributed to the violation of the $SU(3)$ symmetry.
Magnetic moments of the positive parity 70-plet baryons are estimated within the non relativistic quark model and QCD sum rules method. It is found that the magnetic moments of the 70-plet baryons can be expressed in terms of the D and F couplings and exhibit unitary symmetry. The QCD sum rules for the magnetic moments of the 70-plet octet baryons are formulated. Comparison of magnetic moments of 56-plet and 70-plet baryons predicted from QCD sum rules are presented.
Diagonal and transition magnetic moments of the 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 obtained that the magnetic moments of all baryons, except $Λ_b^0$, $Σ_c^+$ and $Ξ_c^{\prime +}$, are quite large. It is also found that the transition magnetic moments between neutral negative parity heavy $Ξ_Q^{\prime 0}$ and $Ξ_Q^0$ baryons are very small. Magnetic moments of the $Σ_Q \to Λ_Q$ and $ Ξ_Q^{\prime \pm} \to Ξ_Q^\pm$ transitions are quite large and can be measured in further experiments.
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 $Ξ_Q^{\prime 0}$ and $Ξ_Q^0$ baryons are very small. Magnetic moments of the $Σ_Q \to Λ_Q$ and $ Ξ_Q^{\prime \pm} \to Ξ_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.
A possible manifestation of an additional light gauge boson $A^\prime$, named as Dark Photon, associated with a group $U(1)_{\rm B-L}$ is studied in neutrino electron scattering experiments. The exclusion plot on the coupling constant $g_{\rm B-L}$ and the dark photon mass $M_{A^\prime}$ is obtained. It is shown that contributions of interference term between the dark photon and the Standard Model are important. The interference effects are studied and compared with for data sets from TEXONO, GEMMA, BOREXINO, LSND as well as CHARM II experiments. Our results provide more stringent bounds to some regions of parameter space.
The magnetic moments of heavy sextet $J^P = {1\over 2}^+$ 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.
We calculate the magnetic dipole and electric quadrupole moments associated with the radiative $Ω_{Q}^{*}\rightarrowΩ_{Q}γ$ and $Ξ_{Q}^{*}\rightarrowΞ^{\prime}_{Q}γ$ transitions with $Q=b$ or $c$ in the framework of light cone QCD sum rules. It is found that the corresponding quadrupole moments are negligibly small while the magnetic dipole moments are considerably large. A comparison of the results on the considered multipole moments as well as corresponding decay widths with the predictions of the vector dominance model is performed.
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 $χ_{c0}$ 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.