научный журнал по физике Ядерная физика ISSN: 0044-0027

POKROVSKY YU. E. — 2014 г.

The lowest frequency of the dipole mode (surface gravity wave) of the Sun and some other stars is shown to be close to the orbital frequency of a trial body near the star surface, as well as the wave amplitude is shown to be resonantly increased to the values large enough to be observed. Therefore the Sun is considered to be a sensitive detector for hypothetical compact cosmic bodies made of dark matter particles. In this connection some possible characteristics of the dark matter bodies (DMB) are discussed, and DMB orbits in the Sun are calculated within a standard solar model in order to compare the wave amplitudes with data for the solar surface oscillations, and to estimate the masses and radii of the DMB. As well, some possible phenomena in star and planet structures are discussed with special attention on generation of flares of high X-ray classes, specific behavior of the Moon dust, formation of short-time vertical flows in deserts, oceans, and atmospheres on the Earth and other planets.

MARTYNENKO A.P., TRUNIN A.M. — 2014 г.

On the basis of perturbative QCD and relativistic quark model we calculate relativistic and bound state corrections in the production processes of a pair of P-wave charmonium states. Relativistic factors in the production amplitude are taken into account connected with the relative motion of heavy quarks and the transformation law of the bound-state wave function to the reference frame of the moving P-wave mesons. Relativistic corrections to the quark bound-state wave functions in the rest frame are considered by means of the Breit-like potential. It turns out that the examined effects change essentially nonrelativistic results of the cross section for the reaction e+ + e- → hc + XcJ at the center-of-mass energy √S = 10,6 GeV.

DENICOL G.S., KOIDE T., MISHUSTIN I.N., TORRIERI G. — 2014 г.

Starting from the linear sigma model with constituent quarks we derive hydrodynamic equations which are coupled to the order-parameter field, e.g. the chiral fluid dynamics. For a static system in thermal equilibrium this model leads to a chiral phase transition which, depending on the choice of the quark–meson coupling constant , could be a crossover or a first order one. We investigate the stability of the chiral fluid in the static and expanding background by considering the evolution of perturbations with respect to the mean-field solution. In the static background the spectrum of plane-wave perturbations consists of two branches, one corresponding to the sound waves and another to the -meson excitations. For large these two branches cross and the excitation spectrum acquires exponentially growing modes. The stability analysis is also done for the Bjorken-like background solution by explicitly solving the time-dependent differential equation for perturbations in the space. In this case the growth rate of unstable modes is significantly reduced.

HWASH WALEED S., RADIMAN SHAHIDAN, YAHAYA REDZUWAN — 2014 г.

This study aimed to investigate the two-neutron halo nucleus of B using the cluster model. The interaction between the two neutrons and deformed core B was treated as a rigid rotor with a deformed Woods–Saxon potential and a spin–orbit interaction. The three-body description of the B nucleus was carried out using the Jacobi coordinates method. The three-body system of B was described with the hyperspherical harmonic method. The three-body energy-dependent on the deformation of the core was also studied. The binding energy, matter radius of B, and deformation of B were calculated by normalization and by using experimental data. Comparison of the results with experimental data demonstrated the deformation of the core, especially of the prolate shapes.

SKALOZUB V.V. — 2014 г.

Simple representation for the average value of the -boson one-loop polarization tensor in a magnetic field , calculated in the ground state of the tree-level spectrum, is derived. It corresponds to Demeurs formula for electron in QED. The energy of this state, describing effective particle mass, is computed by solving the Schwinger–Dyson equation. As application, we investigate the effective mass squared at the threshold of the tree-level instability, , and show that it is positive. In this way the stability of the -boson spectrum is established. Some peculiarities of the results obtained and other applications are discussed.

MEHRABAN HOSSEIN, MOHAMMADI BEHNAM — 2014 г.

The hadronic decay of is analyzed by using “QCD factorization” (QCDF) method and final-state interaction (FSI). First, the decay is calculated via QCDF method and the annihilation graphs only exist in this method. Hence, the FSI must be seriously considered to solve the decay and the and via the exchange of and mesons are chosen for the intermediate states. To estimate the intermediate state amplitudes, the QCDF method is again used. These amplitudes are used in the absorptive part of the diagrams. The experimental branching ratio of decay is less than and our results according to the QCDF method and FSI are and , respectively.

IRGAZIEV B.F. — 2014 г.

In this article the results of the evaluation of the contribution of nuclear disintegration, based on the basis of diffraction theory in the Coulomb breakup at an energy of 156 MeV is presented. Comparison of the results of the calculation with the experimental data of Kiener et al. [Phys. Rev. C 44, 2195 (1991)] gives evidence for the dominance of the Coulomb dissociation mechanism and contribution of nuclear distortion, but essentially smaller than the value reported by Hammache et al. [Phys. Rev. C 82, 065803 (2010)] and Summerer [Prog. Part. Nucl. Phys. 66, 298 (2011)].

KHODEL V.A., POPOV K.G., SHAGINYAN V.R. — 2014 г.

This short review paper is devoted to 90th anniversary of S.T. Belyaev birthday. Belyaevs ideas associated with the condensate state in Bose interacting systems have stimulated intensive studies of the possible manifestation of such a condensation in Fermi systems. In many Fermi systems and compounds at zero temperature a phase transition happens that leads to a quite specific state called fermion condensation. As a signal of such a fermion condensation quantum phase transition (FCQPT) serves unlimited increase of the effective mass of quasiparticles that determines the excitation spectrum and creates flat bands. We show that the class of Fermi liquids with the fermion condensate forms a new state of matter. We discuss the phase diagrams and the physical properties of systems located near that phase transition. A common and essential feature of such systems is quasiparticles different from those suggested by L.D. Landau by crucial dependence of their effective mass on temperature, external magnetic field, pressure, etc. It is demonstrated that a huge amount of experimental data collected on different compounds suggest that they, starting from some temperature and down, form the new state of matter, and are governed by the fermion condensation. Our discussion shows that the theory of fermion condensation develops completely good description of the NFL behavior of strongly correlated Fermi systems. Moreover, the fermion condensation can be considered as the universal reason for the NFL behavior observed in various HF metals, liquids, compounds with quantum spin liquids, and quasicrystals. We show that these systems exhibit universal scaling behavior of their thermodynamic properties. Therefore, the quantum critical physics of different strongly correlated compounds is universal, and emerges regardless of the underlying microscopic details of the compounds. This uniform behavior, governed by the universal quantum critical physics, allows us to view it as the main characteristic of the new state of matter.

ASADI AMIN, MEHRABAN HOSSEIN — 2014 г.

In this research the exclusive decay of is calculated by QCD factorization (QCDF) method and final-state interaction (FSI). First, the decay is calculated via QCDF method. The result that is found by using the QCDF method is less than the experimental result. So FSI is considered to solve the decay. For this decay, the and via the exchange of , and , mesons are chosen for the intermediate states. The above intermediate states are calculated by using the QCDF method. The experimental branching ratio of decay is and our results calculated by QCDF and FSI are and , respectively.

BALBUTSEV E.B., MOLODTSOVA I.V., SCHUCK P. — 2014 г.

Investigations of the nuclear scissors mode in the frame of the Wigner Function Moments (WFM) method leading to the discovery of the new types of the nuclear collective motion are reviewed. It is demonstrated how the generalization of WFM method to take into account spin degrees of freedom allows one to reproduce all earlier described qualitative features of the conventional (neutron–proton) nuclear scissors (deformation dependence of the energy and transition probabilities, connection with isovector GQR implying the Fermi surface deformation, flows) and allows one to reveal a variety of new collective modes: isovector and isoscalar spin scissors, the relative motion of the orbital angular momentum and spin, isovector and isoscalar spin-vector GQR, spin-flip excitations.

BALDO M., BURGIO G.F., CENTELLES M., SHARMA B.K., VINAS X. — 2014 г.

Within a microscopic approach the structure of Neutron Stars is usually studied by modelling the homogeneous nuclear matter of the core by a suitable Equation of State, based on a many-body theory, and the crust by a functional based on a more phenomenological approach. We present the first calculation of Neutron Star overall structure by adopting for the core an Equation of State derived from the Brueckner–Hartree–Fock theory and for the crust, including the pasta phase, an Energy Density Functional based on the same Equation of State, and which is able to describe accurately the binding energy of nuclei throughout the mass table. Comparison with other approaches is discussed. The relevance of the crust Equation of State for the Neutron Star radius is particularly emphasised.

KOLOMIETZ V.M., RADIONOV S.V., REZNYCHENKO B.V. — 2014 г.

The gamma-quanta emission is considered within the framework of the non-Markovian kinetic theory. It is shown that the memory effects have a strong influence on the spectral distribution of gamma quanta in the case of long-time relaxation regime. It is shown that the gamma radiation can be used as a probe for both the time-reversible hindrance force and the dissipative friction caused by the memory integral.

ANTIA A.D., HASSANABADI H., IKOT A.N., YAZARLOO B.H., ZARRINKAMAR S. — 2014 г.

We have investigated the Manning–Rosen potential under the framework of spin and pseudospin symmetries with generalized tensor interaction (GTI) using the parametric generalization of Nikiforov–Uvarov method. We have obtained the energy eigenvalues and the corresponding eigenfunction. We have also reported some numerical results and figures to show the effect of tensor interaction. The role of GTI is investigated in details. It is seen that the degenerate doublets in spin and pseudospin are changed due to the presence of GTI.

ERMAMATOV M.J., KUMAR VIKAS, SRIVASTAVA P.C. — 2014 г.

In the present paper nuclear structure properties of Y isotopes have been investigated using large-scale shell-model calculations within the full model space. The calculations have been performed with JUN45 and jj44b effective interactions that have been proposed for use in the , , , model space for both protons and neutrons. Reasonable agreement between experimental and calculated values are obtained. This work will add more information to the previous study by the projected shell model [Eur. Phys. J. A 48, 138 (2012)], where full-fledged shell-model calculations were proposed for these nuclei.

BAAS N.A., FEDOROV D.V., JENSEN A.S., RIISAGER K., VOLOSNIEV A.G., ZINNER N.T. — 2014 г.

We consider few-body bound state systems and provide precise definitions of Borromean and Brunnian systems. The initial concepts are more than a hundred years old and originated in mathematical knot-theory as purely geometric considerations. About thirty years ago they were generalized and applied to the binding of systems in nature. It now appears that recent generalization to higher-order Brunnian structures may potentially be realized as laboratory-made or naturally occurring systems. With the binding energy as measure, we discuss possibilities of physical realization in nuclei, cold atoms, and condensed-matter systems. Appearance is not excluded. However, both the form and the strengths of the interactions must be rather special. The most promising subfields for present searches would be in cold atoms because of external control of effective interactions, or perhaps in condensed-matter systems with non-local interactions. In nuclei, it would only be by sheer luck due to a lack of tunability.

ISAKOV V.I. — 2014 г.

In the framework of the two-group configuration model we obtain formulas for the reduced transition rates for beta and gamma transitions in even–even, odd–odd, even–odd, and odd–even nuclei. We explored dependencies of the transition rates on the occupancies of the involved subshells, as well as on the spin values of the initial and final states. The obtained formulas are useful for the qualitative spectroscopic analysis of experimental data, particulary in the regions of magicity, including the regions of the “remote” nuclei.

DMITRIEV V.F., MILSTEIN A.I., SALNIKOV S.G. — 2014 г.

We use the Paris nucleon-antinucleon optical potential for explanation of experimental data in the process near threshold. It turns out that final-state interaction due to Paris optical potential allows us to reproduce available experimental data. It follows from our consideration that the isoscalar form factor is much larger than the isovector one.

EFROS V.D. — 2014 г.

A method to calculate reactions in quantum mechanics is outlined. It is advantageous, in particular, in problems with many open channels of various nature, i.e., when energy is not low. In the difference with more conventional approaches the dynamics calculations to be performed are bound-state type-calculations. Continuum spectrum states never enter the game. In the course of calculations there is no need to consider reaction channels, as well as reaction thresholds. Reaction channels and thresholds come into play at merely the kinematics level and only after a dynamics calculation is done.

ERSHOV S.N., VAAGEN J.S., ZHUKOV M.V. — 2014 г.

A generalized Prufer transformation within the framework of the modified variable phase method has been used for numerical solution of coupled radial Schrodinger equations at negative energies. The method has been applied to calculations of the Borromean two-neutron halo nucleus C, for which an unusually large value of the matter radius has recently been extracted from measured reaction cross sections. The giant size can only be explained by an extremely loose binding that is, however, not yet known experimentally. Within the three-body cluster model we have explored the sensitivity of the C matter and charge radii and soft dipole mode excitations to the two-neutron separation energy.

BARABANOV M. YU., OLSEN S.L., VODOPYANOV A.S. — 2014 г.

The spectroscopy of charmonium is discussed. It is a good testing tool for the theories of strong interactions, including: QCD in both the perturbative and non-perturbative regimes, LQCD, potential models and phenomenological models. For this purpose an elaborated analysis of the charmonium spectrum is given, and attempts to interpret recent experimental data in the above threshold region are considered. Experiments using antiproton beams take advantage of the intensive production of particle–antiparticle pairs in antiproton–proton annihilations. Experimental data from different collaborations are analyzed with special attention given to new states with hidden charm that were discovered recently. Some of these states can be interpreted as higher-laying , , and wave charmonium states. But much more data on different decay modes are needed before firmer conclusions can be made. These data can be derived directly from the experiments using a high quality antiproton beam with momenta ranging from 1 to 15 GeV/ .