arXiv subjects
Publications and source records attributed to V. S. Zamiralov.
Dubnicka-Dubnickova-Kuraev (DDK) sum rules are considered. It is shown that integrals over differences of the total photoproduction cross-sections on octet baryons could be understood in terms of unitary symmetry approach. All the DDK sum rules for these quantities are expressed in terms of only three parameters.
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.
Using the calculated values of the strong coupling constants of the heavy sextet spin-3/2 baryons to sextet and antitriplet heavy spin-1/2 baryons with light mesons within the light cone QCD sum rules method, and vector meson dominance assumption, the radiative decay widths are calculated. These widths are compared with the "direct" radiative decay widths predicted in the framework of the light cone QCD sum rules.
The heavy spin--3/2 baryon--heavy spin--1/2 baryon vertices with light vector mesons are studied within the light cone QCD sum rules method. These vertices are parametrized in terms of three coupling constants. These couplings are calculated for all possible transitions. It is shown that correlation functions for these transitions are described by only one invariant function for every Lorenz structure. The obtained relations between the correlation functions of the different transitions are structure independent while explicit expressions of invariant functions depend on the Lorenz structure.
The strong coupling constants between light vector mesons and octet-decuplet baryons are calculated in framework of the light cone QCD sum rules, taking into account SU(3) flavor symmetry breaking effects. It is shown that all strong coupling constants can be represented in terms of a single universal function. Size of the SU(3) symmetry breaking effects are estimated.
Possible mixing and its consequences of heavy cascade baryons Ξ-Ξ^\prime is analyzed and its importance in the analysis of their characteristics is shown within the non-relativistic quark model and QCD sum rules.
Using the most general form of the interpolating current of the baryons, the strong coupling constants of the light vector mesons with the octet baryons are calculated within the light cone QCD sum rules. The SU(3)_f symmetry breaking effects are taken into account in the calculations. It is shown that each of the electric and magnetic coupling constants can be described in terms of three universal functions. A detailed comparison of the results of this work on aforementioned couplings with the existing theoretical results is presented.
Weak radiative hyperon decays are considered in the framework of a quark model. The phenomenological model includes 1-quark transitions with the effective $sdγ$-vertex and 2-quark ones with the W-exchange $s+u\to u+d+γ$ and turns out to describe well the data and gives predictions for asymmetry of the decays $Λ\to n+γ$ and $Ξ^-\to Σ^- +γ$.
New relations between QCD Borel sum rules for strong coupling constants of K-mesons to baryons are derived. It is shown that starting from the sum rule for the coupling constants $g_{πΣΣ}$ and $g_{πΣΛ}$ it is straightforward to obtain corresponding sum rules for the $g_{K Y N}$, $g_{K Y Ξ}$ couplings, $Y=Σ,Λ$.
New relations between QCD Borel sum rules for magnetic moments of Sigma^0 and Lambda hyperons are constructed. It is shown that starting from the sum rule for the Sigma^0 hyperon magnetic moment it is straightforward to obtain the corresponding sum rule for the Lambda hyperon magnetic moment et vice versa.
It is shown that in the framework of GIM model,the parity-violating (PV) $Σ^{+}(uus) \Rightarrow p(uud) + γ$ decay amplitude does not vanish but just transforms into another PV decay amplitude, namely, of the $Ω^{+}_{cc}(ccs)\to Ξ^{+}_{cc}(ccd)+γ$ decay. The known result is used that the relevant part of the CP-invariant effective current$\times$ current Hamiltonian changes sign under simultaneous quark changes $d\leftrightarrow s$ and $u\leftrightarrow c$. So, asymmetry of $Σ^{+} \Rightarrow p + γ$ decay should not vanish in contrast to the Hara result of the old-fashioned $SU(3)_{f}$ model. At the same time, the zero asymmetry prediction persists for the $ Ξ^{-} \Rightarrow Σ^{-} + γ$ decay.
It is shown that upon considering an alternative form of a parity-violating part of the transition electromagnetic current it is possible to reformulate Hara theorem in a way that it does not forbid any more nonzero asymmetry in the hyperon weak radiative decays $Σ^{+} \to p+γ$ and $Ξ^{-} \to Σ^{-}+γ$ in the limit of exact $SU(3)_{f}$ symmetry thus resolving a contradiction with the data and maybe revealing hitherto unseen transition toroid dipole moments. A result is consistent with the traditional one on the single-quark weak radiative transition models. We have also reproduced Vasanti formula at the quark level. As for two-quark weak radiative transitions we have found that the important part of it contains also a toroid dipole moment contribution which seems to be an intrinsic reason of the apparent contradiction between the Hara theorem conclusion and quark model results for hyperon weak radiative decays.
It is shown that the baryon magnetic moment descriptions in the frameworks of the chiral model ChPT and the quark soliton $χQSM $ one are practically identical. The main difference from the traditional unitary symmetry models proves to be in terms due to the pionic current contribution into the magnetic moments of nucleons and in the prediction for the $Λ$ magnetic moment.
It is shown that an alternative form of the parity-nonconserving (PNC) transition electromagnetic current resolves partly a puzzle with the Hara theorem. New formulation of it has allowed PNC weak radiative hyperon transitions of the charged hyperons $Σ^{+} \Rightarrow p + γ$ and $Ξ^{-} \Rightarrow Σ^{-} + γ$ revealing hitherto unseen transition toroid dipole moment.