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E. N. Bukina

Publications and source records attributed to E. N. Bukina.

7 recordsLinked to original sources
arXiv2000

Hara Theorem, GIM model, and Asymmetry in Weak Radiative Hyperon Decays

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.

hep-ph↗
arXiv1999

Alternative Form of the Parity-Violating Current for the Hyperon Weak Radiative Decays and Hara Theorem

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.

hep-ph↗
arXiv1998

The gauge freedoms of enlarged Helmholtz theorem and the Neumann --- Debye potentials; their manifestation in the multipole expansion of conserved current

We discuss gauge freedom within the scope of the enlarged Helmholtz theorem and Neumann-Debye decomposition and then demonstrate its realization for the multipole expansion of a electromagnetic current with distinguished toroid moment family. The exact solution to the latter problem was obtained in 1974, but answers to some purely mathematical questions raised by I.B.~French and Y.~Shimamoto~\cite{French} about 40 years ago are given in this paper for the first time.

math-ph↗
arXiv1998

Upon symmetry of baryon magnetic moments in the chiral and the quark-soliton models

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.

hep-ph↗
arXiv1998

Generalized Gordon Identities, Hara Theorem and Weak Radiative Hyperon Decays

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.

hep-ph↗
arXiv1997

Evaluation of Vacuum Energy for Tensor Fields on Spherical Spaces

The effective one-loop potential on $R^{m+1}\times S^N$ spaces for massless tensor fields is evaluated. The Casimir energy is given as a value of $ζ-$ function by means of which regularization is made. In even- dimensional spaces the vacuum energy contains divergent terms coming from poles of $ζ(s,q)$ at $s=1$, whereas in odd-dimensional spaces it becomes finite.

quant-ph↗