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T. M. Aliev

Publications and source records attributed to T. M. Aliev.

At least 55 records · Page 3Linked to original sources

The mass and residues of radially and orbitally excited doubly heavy baryons in QCD

The mass and residues of the first radial and orbital excitations of $J=\frac{1}{2}$ baryons containing two heavy quarks (b or c) are calculated within the QCD sum rules method. In calculations, the general forms of the interpolating currents with symmetric and anti-symmetric forms with respect to the exchange of heavy quarks have been used. Our results on the spectroscopic parameters of doubly heavy baryons are compared with the predictions of other theoretical approaches.

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Radiative decays of the p-wave charmed heavy baryons

The radiative decays of the p-wave charmed heavy baryons to the ground state baryon states are studied in the framework of the light cone QCD sum rules method. Firstly, the transition form factors that describe these transitions are estimated, and then using these form factors the corresponding decay widths are calculated. A comparison of our results on the decay widths with those predicted by the other approaches existing in literature is performed.

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Determination of the quantum numbers of $Σ_b(6097)^{\pm}$ via their strong decays

The progresses in the experimental sector have been the harbinger of the observations of many new hadrons. Very recently, LHCb Collaboration announced the observation of two new $Σ_b(6097)^{\pm}$ states in the $Λ^0_bπ^{\pm}$ invariant mass distribution, which are considered as the excited states of the ground state $Σ^{(*)}_b$ baryon. Though, almost all of the ground state baryons have been observed, having a limited number of excited states observed so far makes them intriguing. Understanding the properties of the excited baryons improve our knowledge on the strong interaction as well as the nature and internal structures of these baryons. To specify the quantum numbers of the $Σ_b(6097)^{\pm}$ an analysis on their strong decays to $Λ_b^0$ and $π^{\pm}$ is performed within the light cone QCD sum rule formalism. To this end, they are considered as possible $1P$ or $2S$ excitation of either the ground state $Σ_b$ baryon with $J=\frac{1}{2}$ or $Σ_b^{*}$ baryon with $J=\frac{3}{2}$. The corresponding masses are also calculated considering the same scenarios for their quantum numbers. The results of the analyses indicate that the $Σ_b(6097)^{\pm}$ baryons are excited $1P$ baryons having quantum numbers $J^P=\frac{3}{2}^-$.

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Study of the $Λ_{b} \to N^\ast \ell^+ \ell^- $ decay in light cone sum rules

The form factors of the $Λ_{b} \to N^\ast \ell^+ \ell^-$ decay are calculated in the framework of the light cone QCD sum rules. In the calculations the contribution of the negative parity $Λ_b^\ast$ baryon is eliminated by constructing the sum rules for different Lorentz structures. Furthermore the branching ratio of the semileptonic $Λ_b \to N^\ast \ell^+ \ell^-$ decay is calculated. The numerical study for the branching ratio of the $Λ_{b} \to N^\ast \ell^+ \ell^-$ decay indicates that it is quite large and could be measurable at future planned experiments to be conducted at LHCb.

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Radiative decays of the heavy tensor mesons in light cone QCD sum rules

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.

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Structure of the $Ξ_b(6227)^-$ Resonance

We explore the recently observed $Ξ_b(6227)^{-}$ resonance to fix its quantum numbers. To this end, we consider various possible scenarios: It can be considered as either 1P/2S excitations of the $Ξ_b^-$ and $Ξ_b'(5935)^{-}$ ground state baryons with spin-$\frac{1}{2}$ or 1P/2S excitations of the ground state $Ξ_b(5955)^{-}$ with spin-$\frac{3}{2}$. We calculate the masses of the possible angular-orbital $1P$ and $2S$ excited states corresponding to each channel employing the QCD sum rule technique. It is seen that all the obtained masses are in agreement with the experimentally observed value, implying that the mass calculations are not enough to distinguish the quantum numbers of the state under question. Therefore, we extend the analysis to investigate the possible decays of the same excited states into $Λ_b^0 K^-$ and $Ξ_b^-π$. Using the light cone QCD sum rule method, we calculate the corresponding strong coupling constants, which are used to extract the decay widths of the modes under consideration. Our results on decay widths indicate that the $Ξ_b(6227)^{-}$ is $1P$ angular-orbital excited state of the $Ξ_b(5955)^{-}$ baryon with quantum numbers $J^P=\frac{3}{2}^{-}$.

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Nature of the $Ω$(2012) through its strong decays

We extend our previous analysis on the mass of the recently discovered $Ω(2012)$ state by investigation of its strong decays and calculation of its width employing the method of light cone QCD sum rule. Considering two possibilities for the quantum numbers of $Ω(2012)$ state, namely $1P$ orbital excitation with $J^P=\frac{3}{2}^-$ and $2S$ radial excitation with $J^P=\frac{3}{2}^+$, we obtain the strong coupling constants defining the $Ω(1P/2S)\rightarrowΞK$ decays. The results of the coupling constants are then used to calculate the decay width corresponding to each possibility. Comparison of the obtained results on the total widths in this work with the experimental value and taking into account the results of our previous mass prediction on the $Ω(2012)$ state, we conclude that this state is $1P$ orbital excitation of the ground state $Ω$ baryon, whose quantum numbers are $J^P=\frac{3}{2}^-$.

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Determination of $f_0 - a_0^0$ mixing angle from QCD sum rules

By assuming that the $f_0$ and $a_0^0$ mesons are mixed states of the two-quark - tetraquark, the mixing angle between them is estimated within QCD sum rules method, and it is obtained that the mixing angle is $(6.03 \pm 0.08)^\circ$. Our prediction on mixing angle can be checked in further experiments which can shed light on choosing the "right" structure of $f_0$ and $a_0^0$ mesons.

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On the nature of $Ξ_c(2930)$

The single charmed excited $Ξ_c(2930)$ state was discovered many years ago by BABAR collaboration and recently confirmed by Belle experiment. However, both of these experiments, unfortunately, could not fix the quantum numbers of this particle and its nature is under debates. In the present study, we calculate its mass and width of its dominant decay to $ Λ_c K $. To this end we consider $Ξ_c(2930)$ state once as angularly excited and then radially excited single charmed baryon in $ Ξ_c$ channel. Comparison of the obtained results with the experimental data suggests assignment of $Ξ_c(2930)$ state as the angular excitation of the ground state $Ξ_c$ baryon with quantum numbers $J^P=\frac{1}{2}^{-}$.

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Form factors for the rare $Λ_{b}(Λ_{b}^*)\rar N\ell^+\ell^- $ decays in light cone QCD sum rules

Form factors of the rare $Λ_{b}(Λ_{b}^*)\to N\ell^{+}\ell^{-}$ 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 the form factors, the branching ratios of the considered decays are estimated. The numerical survey for the branching ratios of the $Λ_b \rar N\ell^+\ell^- $ and $Λ_b^\ast \rar N\ell^+\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.

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Interpretation of the newly discovered $Ω$(2012)

Very recently Belle Collaboration reported observation of a narrow state called $Ω(2012)$ with mass $2012.4 \pm 0.7$~(stat)~$\pm 0.6$(syst)~MeV and width $6.4^{+2.5}_{-2.0}$~(stat)~$\pm 1.6$~(syst)~MeV. We calculate the mass and residue of $Ω(2012)$ state by employing the QCD sum rule method. Comparison of the obtained results with the experimental data allows us to interpret this state as $1P$ orbital excitation of the ground state $Ω$ baryon, i.e. with quantum numbers $J^P=\frac{3}{2}^-$.

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Reanalysis of $Ω_c \rightarrow Ξ_c^+ K^-$ decay in QCD

The strong coupling constants of newly observed $Ω_c^0$ baryons with spin $J = \frac{1}{2}$ and $J = \frac{3}{2}$ decaying into $Ξ_c^{+} K^{-}$ are estimated within light cone QCD sum rules. The calculations are performed within two different scenarios on quantum numbers of $Ω_c$ baryons: a) all newly observed $Ω_c$ baryons are negative parity baryons, i.e., the $Ω_c(3000)$, $Ω_c(3050)$, $Ω_c(3066)$, and $Ω_c(3090)$ have quantum numbers $J^P = \frac{1}{2}^-$ and $J^P = \frac{3}{2}^-$ states respectively; b) the states $Ω_c(3000)$ and $Ω_c(3050)$ have quantum numbers $J^P = \frac{1}{2}^-$ and $J^P = \frac{1}{2}^+$, while the states $Ω_c(3066)$ and $Ω_c(3090)$ have the quantum numbers $J^P = \frac{3}{2}^-$ and $J^P = \frac{3}{2}^+$, respectively. By using the obtained results on the coupling constants, we calculate the decay widths of the corresponding decays. The results on decay widths are compared with the experimental data of LHC Collaboration. We found out that the predictions on decay widths within these scenarios are considerably different from the experimental data, i.e., both considered scenarios are ruled out.

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Analysis of the structure of $Ξ(1690)$ through its decays

The mass and pole residue of the first orbitally and radially excited $ Ξ$ state as well as the ground state residue are calculated by means of the two-point QCD sum rules. Using the obtained results for the spectroscopic parameters, the strong coupling constants relevant to the decays $Ξ(1690)\rightarrow ΣK$ and $Ξ(1690) \rightarrow ΛK$ are calculated within the light-cone QCD sum rules and width of these decay channels are estimated. The obtained results for the mass of $ \widetildeΞ $ and ratio of the $Br\Big(\widetildeΞ\rightarrow ΣK\Big)/Br\Big(\widetildeΞ\rightarrow ΛK\Big)$, with $ \widetildeΞ $ representing the orbitally excited state in $ Ξ$ channel, are in nice agreement with the experimental data of the Belle Collaboration. This allows us to conclude that the $Ξ(1690)$ state, most probably, has negative parity.

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Light-Cone Distribution Amplitudes of Light $J^{PC}=2^{--}$ Tensor Mesons in QCD

We present a study for two-quark light-cone distribution amplitudes for the $1^3D_2$ light tensor meson states with quantum number $J^{PC}=2^{--}$. Because of the G-parity, the chiral-even two-quark light-cone distribution amplitudes of this tensor meson are antisymmetric under the interchange of momentum fractions of the quark and antiquark in the SU(3) limit, while the chiral-odd ones are symmetric. The asymptotic leading-twist LCDAs with the strange quark mass correction are shown. We estimate the relevant parameters, the decay constants $f_T$ and $f_T^\perp$, and first Gegenbauer moment $a_1^\perp$, by using the QCD sum rule method. These parameters play a central role in the investigation of $B$ meson decaying into the $2^{--}$ tensor mesons.

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Strong coupling constants of negative parity heavy baryons with $π$ and $K$ mesons

The strong coupling constants of negative parity heavy baryons belonging to a sextet and antitriplet representations of $SU_f(3)$ with light $π$ and $K$ mesons are estimated within the light cone QCD sum rules. It is observed that each class of the sextet-sextet, sextet-antitriplet, and antitriplet-antitriplet transitions can be described by only one corresponding function. The pollutions arising from the positive to positive, positive to negative, and negative to positive parity baryons transitions are eliminated by constructing sum rules for different Lorentz structures. The obtained coupling constants are compared with the ones for the positive parity heavy baryons.

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Radial Excitations of the Decuplet Baryons

The ground and first excited states of the decuplet baryons are studied using the two-point QCD sum rule approach. The mass and residue of these states are computed and compared with the existing experimental data and other theoretical predictions. The results for the masses of the ground state particles as well as the excited $ Δ$ and $ Σ^{*} $ states are in good consistency with experimental data. Our results on the excited $ Ξ^{*} $ and $ Ω^{-} $ states reveal that the experimentally poorly known $ Ξ(1950) $ and $ Ω^{-}(2250) $ can be assigned as the first excited states in $ Ξ^{*} $ and $ Ω^{-} $ channels, respectively.

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Scalar Unparticle Signals at the LHC

If the scale invariance exists in nature, the so-called unparticle physics may become part of reality. The only way to refute or confirm this idea is through the experiments one of which is the Large Hadron Collider (LHC). One of the peculiar properties of the unparticle stuff is that it gives striking multi-photon signals which has been studied through only the unparticle self-interactions. By considering not only the self-interactions of unparticles but also all the other possible contributions, which are dominant, a detailed study of the processes, within a scalar unparticle scenario, $pp\to 4γ$, $pp\to 2γ2g$, $pp\to 2γ2\ell$, $pp\to 4e$, $pp\to 4μ$ and $pp\to 2e2μ$ at $\sqrt{s}=14$ TeV at the LHC is carried out. We use basic selection cuts and analyze various distributions to discriminate the signals over the Standard Model backgrounds and discuss what seems to be the most likely channel among the above ones for an indirect manifestation of unparticle effects. We follow a new approach to tackle the issue with the three-point correlation function for the scalar unparticle self-interactions. We also obtain the exclusion region in the unparticle parameter space from the available two-photon data of the LHC.

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Magnetic dipole moments of the negative parity $J^{PC}=2^{--}$ mesons in QCD

Magnetic dipole moments of the negative parity light and heavy tensor mesons are calculated within the light cone QCD sum rules method. The results are compared with the positive parity counterparts of the corresponding tensor mesons. The results of the analysis show that the magnetic dipole moments of the negative parity light mesons are smaller compared to those of the positive parity mesons. Contrary to the light meson case, magnetic dipole moments of the negative parity heavy mesons are larger than the ones for the positive parity mesons.

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