arXiv subjects

V. B. Belyaev

Publications and source records attributed to V. B. Belyaev.

At least 37 records · Page 2Linked to original sources

arXiv2001

Coherent Photoproduction of eta-mesons on Three-Nucleon Systems

A microscopic few-body description of near-threshold coherent photoproduction of the eta-meson on tritium and He3 targets is given. The photoproduction cross-section is calculated using the Finite Rank Approximation (FRA) of the nuclear Hamiltonian. The results indicate a strong final state interaction of the eta-meson with the residual nucleus. Sensitivity of the results to the choice of the eta-N T-matrix is investigated. The importance of obeying the two-body unitarity condition in the eta-N system is demonstrated.

nucl-th↗

arXiv2001

Microscopic description of $η$-photoproduction on light nuclei

A microscopic four-body description of near-threshold coherent photoproduction of the $η$ meson on the (3N)-nuclei is given. The photoproduction cross-section is calculated using the Finite Rank Approximation (FRA) of the nuclear Hamiltonian. The results indicate that the final state interaction of the $η$ meson with the residual nucleus plays an important role in the photoproduction process. Sensitivity of the results to the choice of the $ηN$ T-matrix is investigated. The importance of obeying the condition of $ηN$ unitarity is demonstrated.

nucl-th↗

arXiv2001

Search for Nuclear Reactions in Water Molecules

A possibility for molecular-nuclear transitions to occur was recently predicted for some few-atomic systems. Among others, the molecule of ordinary water was shown to be a candidate for this effect due to a presence of (1-, 4.522 MeV) resonance in 18Ne nucleus. A search for traces of nuclear reactions was carried out for condenced and vaporous phases of water, with the use of low-background annihilation spectrometry. The measurements were performed under conventional conditions and under conditions of the Baksan Neutrino Observatory.

nucl-ex↗

arXiv2001

Low energy scattering and photoproduction of $η$-mesons on deuterons

Photo-production of $η$-mesons and their collisions with light nuclei are studied within the Alt-Grassberger-Sandhas (AGS) formalism for different parameters of $ηN$ interaction. A three-body resonance or a quasi-bound state is found close to the $ηd$ threshold. Expected manifestation of this resonant behavior of $ηd$ elastic scattering in various processes involving $ηd$-system in their final states was found in calculations of the $γd \to ηd$ reaction in the framework of modified AGS equations. These calculations revealed peaks in the energy dependence of the total cross-section almost at the same energies as in the elastic $ηd$ scattering. Meanwhile, such peaks did not appear in the impulse approximation (i.e. when $ηd$ resonance was not taken into account). This sheds some light on the nature of the enhancement of $η$ photo-production on deuteron observed recently in the low energy experiments.

nucl-th↗

arXiv2001

Photoproduction of $η$-mesons off light nuclei

Photoproduction of $η$-mesons off deuteron is studied within the Alt-Grassberger-Sandhas formalism for different parameters of $ηN$ interaction. The calculations revealed peaks in the energy dependence of the total cross-section.

nucl-th↗

arXiv2000

Perturbation of a lattice spectral band by a nearby resonance

A soluble model of weakly coupled "molecular" and "nuclear" Hamiltonians is studied in order to exhibit explicitly the mechanism leading to the enhancement of fusion probability in case of a narrow near-threshold nuclear resonance. We, further, consider molecular cells of this type being arranged in lattice structures. It is shown that if the real part of the narrow nuclear resonance lies within the molecular band generated by the intercellular interaction, an enhancement, proportional to the inverse width of the nuclear resonance, is to be expected.

cond-mat.mtrl-sci↗

arXiv2000

Experimental search for molecular-nuclear transitions in water

Experimental search for molecular-nuclear transitions H_2O\to^{18}Ne^*(4.522,1^-)\to^{18}F\to^{18}O in water molecules was carried out. The measurements were performed in a low-background laboratory at the Baksan Neutrino Observatory. Under the assumption that the above transitions take place, the estimate for the half-life time of water molecule was found to be about 10^{18} years.

nucl-ex↗

arXiv2000

First Single Bubble Sonoluminescence in Dubna

At the Institute in Physical-Technical Problems experiments on sonoluminescence was started by our group at the beginning of 1998. The study was focused at properties of the SBSL, and the aim was to find more optimum conditions for a search for some recently predicted rare effects in SBSL- process.

quant-ph↗

arXiv1999

Experiments on Sonoluminescence: Possible Nuclear and QED Aspects and Optical Applications

Experiments aimed at testing some hypothesis about the nature of Single Bubble Sonoluminescence are discussed. A possibility to search for micro-traces of thermonuclear neutrons is analyzed, with the aid of original low-background neutron counter operating under conditions of the deep shielding from Cosmic and other sources of background. Besides, some signatures of QED-contribution to the light emission in SBSL are under the consideration, as well as new approaches to probe a temperature inside the bubble. An applied-physics portion of the program is presented also, in which an attention is being paid to single- and a few-pulse light sources on the basis of SBSL.

quant-ph↗

arXiv1999

Faddeev-type calculation of eta-d threshold scattering

The scattering length for the eta-meson collision with deuteron is calculated on the basis of rigorous few-body equations (AGS) for various eta-N input. The results obtained strongly support the existence of a resonance or quasi-bound state close to the eta-d threshold.

nucl-th↗

arXiv1999

Low-energy eta-d resonance

Elastic eta-d scattering is considered within the Alt-Grassberger-Sandhas (AGS) formalism for various eta-N input data. A three-body resonant state is found close to the eta-d threshold. This resonance is sustained for different choices of the two-body eta-N scattering length a_{ηN}. The position of the resonance moves towards the eta-d threshold when Re a_{ηN} is increased, and turns into a quasi-bound state at Re a_{ηN}=0.733 fm.

nucl-th↗

arXiv1998

Electron Screening in the 7Be + p -->8B + photon reaction

We evaluate the effect of screening by bound electron in the 7Be + p --> 8B + photon reaction, where 7Be target contains bound electron, in the framework of the adiabatic representation of the three particle problem. A comparison with two other approximations (united atom and folding) is presented. A good agreement between the ``united atom'' approximation and the exact solution is found. We also discuss the screening corrections induced by two K-shell electrons on a 7Be target. The bound electron screening effect consequences for 7Be and 8B solar neutrino fluxes are discussed.

astro-ph↗

arXiv1998

Non-radiative synthesis of Be7 in solar plasma

The nuclear reaction e + He3 + He4 ---> e + Be7 is considered at thermonuclear energies. The motion of the electron is treated within the adiabatic approximation and the He3-He4 scattering state is calculated using an effective He3-He4 potential constructed via the Marchenko inverse scattering method. The reaction rate thus obtained for solar interior conditions is approximately 10^{-4} of the corresponding rate for the radiative capture He3 + He4 ----> Be7 + gamma. However, at the conditions corresponding to the early stages of the primordial nucleosynthesis, the non-radiative fusion is five times faster than the radiative one. The importance of the non-radiative processes for the energy balance in the sun, which for electrons is totally opaque, is discussed.

nucl-th↗

arXiv1998

Electron Screening in 7Be + p --> 8B + photon reaction

We evaluate the effect of screening by bound electron in (7Be,e) + p --> (8B,e) + photon transition in the framework of the adiabatic representation of the three particle problem. Comparison with two approaches (united nucleus and static) is presented. We discuss possible applications of this effect both for Solar Neutrinos and low energy fusion experiments.

nucl-th↗

arXiv1998

The electron screening in OH-->F transition both for bound and scattering states

We estimate the nuclear fusion rates for the transition OH-->F from the ground and excited molecular states and also consider effect of screening of electric charges of nuclei by bound electrons in the case of colliding atoms O and H. We show that the fusion rate for the molecular state is vanishingly small while the electron screening drastically changes the rate for the colliding atoms at kinetic energies up to hundreds of keV. The latter may be of consequence for some astrophysical applications.

nucl-th↗

arXiv1997

Triple collisions (e+p+Be7) in solar plasma

Several nuclear reactions involving the Be7 nucleus, not included into the standard model of the pp-chain, are discussed. A qualitative analysis of their possible influence on the fate of the Be7 in solar plasma and of their role in the interpretation of the solar neutrino experiments is given. As an example, the reaction rate of the nonradiative production of B8 in the triple collision p + e^- + Be7 ---> B8 + e^- is estimated in the framework of the adiabatic approximation. For the solar interior conditions the triple collision reaction rate is approximately 10^{-4} of that for the binary process p + Be7 ---> B8 + gamma .

nucl-th↗

arXiv1997

Existence and transitions properties of three-deuteron muonic molecule (3d 2e^- μ^-)

We calculated the energy and the size of the three-deuteron muonic molecule (3d 2e^- μ^-) = D_3 μ. It turns out that this system possesses two equilibrium positions, one at distances typical for muonic molecules and a second one at the usual molecular size. We show, moreover, that the fusion probability of the three deuterons is considerably enhanced due to the existence of a ^6Li^* threshold resonance. Our estimates indicate that this probability is considerably higher than the decay rate of the competing Auger transition.

nucl-th↗

arXiv1997

Nuclear Fusion via Triple Collisions in Solar Plasma

We consider several nuclear fusion reactions that take place at the center of the sun, which are omitted in the standard pp-chain model. More specifically the reaction rates of the nonradiative production of ^3He, ^7Be, and ^8B nuclei in triple collisions involving electrons are estimated within the framework of the adiabatic approximation. These rates are compared with those of the corresponding binary fusion reactions.

nucl-th↗