arXiv subjects

A. L. Barabanov

Publications and source records attributed to A. L. Barabanov.

23 records · Page 2Linked to original sources

arXiv1997

Muon capture by oriented nuclei: new possibilities for studying induced pseudoscalar interaction

Angular distribution of neutrinos (recoil nucleus) in muon capture for an allowed Gamov-Teller transition is considered by taking account of hyperfine effects. This angular distribution is shown to include a correlation of the form P_2(cos A), where A is the angle between the neutrino momentum and the axis specifying the orientation of the initial mesic atom. This correlation, which arises only if the initial mesic atom is aligned, proves highly sensitive to the form factor g_P of induced pseudoscalar interaction. The proposed method for determinating g_P may be realized for the transition 1+ to 2+ from the ground state of the 6-Li nucleus to the narrow resonance of the 6-He nucleus in continuum, as well as in the processes like 10-B(3+) to 10-Be(2+), 11-B(3/2-) to 11-Be(1/2-), 23-Na(3/2+) to 23-Ne(1/2+) with transitions to bound states.

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arXiv1997

T-noninvariant effect in muon capture by 6-Li nucleus with decay to a continuum

The T-noninvariant transverse polarization of neutrons is considered for muon capture by a 6-Li nucleus with decay into a quasistationary 2+ state of the three particle alpha+n+n continuum. This polarization is orthogonal to the plane spanned by the polarization axis of the initial mesic atom and the neutron momentum. The situation in which neutrons that are emitted in the plane orthogonal to the axis of the mesic-atom polarization and which have oppositely directed momenta equal in magnitude are selected is analyzed. The wave function of the final state is constructed by using the method of hyperspherical harmonics. In the approximation of the allowed Gamow-Teller transition 1+ to 2+, this neutron polarization is expressed in terms of the T-noninvariant relative phase of reduced matrix elements for transitions from the 6-Li ground state to various final-state configurations.

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arXiv1995

Model for Resonance Enhancement of P- and T-noninvariant Effects in Neutron Reactions

We consider a simplified model for resonant neutron-nucleus interaction with coupled channels. An analytical solution is given for two coupled channels and arbitrary neutron orbital momentum. A case of a week channel coupling, corresponding to narrow Breit-Wigner resonance, is analyzed in details. As far as the total width of a resonance coincides with the neutron width, the model is directly appropriate only for light nuclei. We study a mixing of two narrow s- and p-wave resonances by P- and P-,T-noninvariant potentials in the first order of perturbation theory. As an example a close-lying pair of s- and p-wave resonances of the $^{35}$Cl nucleus is considered. The favorable possibilities are shown to exist on thick targets for measurements beyond the resonance widths. In particular, an interference minimum near s-wave resonance is of interest for P-odd neutron spin rotation on light spinless nuclei.

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arXiv1994

Does the excited state of the $^3$H nucleus exist?

The suggestion is made that the excited state of the $^3 H$ nucleus found out recently in the reaction $H$ ($^6 He$,$α$) ({\it Pis'ma JETPh\/} {\bf 59} (1994) 301) has spin and parity $1/2^+$ and the same configuration that the ground one of $^6 He$. An amplitude of electromagnetic transition to the triton ground state is strongly suppressed, therefore the excited state cannot be detected in radiative capture of neutrons by deuterons. It is shown that in an elastic nd-scattering a resonance associated with the exited state may be absent due to the destructive interference of potential and resonant scattering phases.

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arXiv1994

Fission fragment orientation and gamma ray emission anisotropy

Experimental data on angular distributions of gamma rays emitted from binary and ternary spontaneous fission of $^{252}{\rm Cf}$ are analyzed. Their difference indicates that the alignment of fragments is higher in ternary fission than in binary one. The consequences of possible relation between the mechanism of ternary fission and the excitation of collective modes during the saddle-to-scission stage are discussed.

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