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Periodic structure of the magnetization reversal (MR) domains is studied within the superconductor-ferromagnetic-superconductor $\phi_0$-junction model. The model is described by the Cauchy problem for the system of nonlinear ordinary equations which is numerically solved by means of the 2-step Gauss-Legendre method. Two versions of parallel implementation on the basis of MPI and OpenMP techniques have been developed. Efficiency of both versions is confirmed by test calculations. An effect of frequency of ferromagnetic resonance on the configuration of MR domains has been investigated., Comment: The XXVI International Scientific Conference of Young Scientists and Specialists (AYSS-2022), JINR, Dubna

Oscillons are localised long-lived pulsating states in the three-dimensional $\phi^4$ theory. We gain insight into the spatio-temporal structure and bifurcation of the oscillons by studying time-periodic solutions in a ball of a finite radius. A sequence of weakly localised {\it Bessel waves} -- nonlinear standing waves with the Bessel-like $r$-dependence -- is shown to extend from eigenfunctions of the linearised operator. The lowest-frequency Bessel wave serves as a starting point of a branch of periodic solutions with exponentially localised cores and small-amplitude tails decaying slowly towards the surface of the ball. A numerical continuation of this branch gives rise to the energy-frequency diagram featuring a series of resonant spikes. We show that the standing waves associated with the resonances are born in the period-multiplication bifurcations of the Bessel waves with higher frequencies. The energy-frequency diagram for a sufficiently large ball displays sizeable intervals of stability against spherically-symmetric perturbations., Comment: 13 pages, 12 figures

Elastic cross sections are calculated and compared with the data on $\pi^{\pm}$ scattering on $^{28}$Si, $^{40}$Ca, $^{58}$Ni, $^{208}$Pb nuclei in the energy range from 130 to 290 MeV. To this end, both the folding optical potential (OP) and the local modified Kisslinger-type OP were calculated, and then the $\pi A$ cross sections were obtained by solving the Klein-Gordon equation to account for the relativization and distortion wave effects. In the folding OPs, the parameters of the elementary $\pi N$ amplitude were fitted when describing the $\pi A$ scattering data, and thus the essential in-medium effect on the parameters of the $\pi N$ amplitude was established since the pion is scattered not on a free but on a bound nuclear nucleon. Fairly good agreement with experimental data was obtained for both models of optical potentials and their forms turn out to be in coincidence in the region of their surfaces., Comment: 16 pages, 6 figures, 2 tables; accepted for publication in Nuclear Physics A

A microscopic analysis of the optical potentials (OPs) and cross sections of quasielastic scattering of $^{12,14}$Be on $^{12}$C at 56 MeV/nucleon and on protons at energy near 700 MeV is carried out. For lower energy scattering the real part of the OP is calculated by using of double-folding procedure accounting for the anti-symmetrization effects, while the imaginary part is obtained on the base of the high-energy approximation (HEA). The HEA is also applied to the calculations of both real and imaginary OPs when solving the relativistic equation for the high-energy proton-nucleus elastic scattering. The neutron and proton density distributions computed in different microscopic models for $^{12}$Be and $^{14}$Be are used. In the present hybrid model of the optical potential the only free parameters are the depths of the real and imaginary parts of OP obtained by fitting the experimental data. The role of the inelastic scattering channel to the first excited $2^{+}$ and $3^{-}$ states in $^{12}$C when calculating the quasielastic cross sections, as well as the modified density of the $^{12}$C target accounting for the surface effects are studied. In addition, the cluster model, in which $^{14}$Be consists of a $2n$-halo and the $^{12}$Be core, is applied to calculate the cross sections of diffraction breakup and stripping reactions in $^{14}$Be+$^{12}$C scattering and longitudinal momentum distributions of $^{12}$Be fragments at energy of 56 MeV/nucleon. A good agreement of the theoretical results with the available experimental data of both quasielstic scattering and breakup processes is obtained., Comment: 12 pages, 10 figures, 3 tables

The magnetization reversal in ${\varphi_0}$-Josephson junction with direct coupling between magnetic moment and Josephson current has been studied. By adding pulse signal, the dynamics of magnetic moment components have been simulated and the full magnetization reversal at different parameters of the junction has been demonstrated. We obtain a detailed pictures representing the intervals of the damping parameter $\alpha$, Josephson to magnetic energy relation $G$ and spin-orbit coupling parameter $r$ with full magnetization reversal. A periodicity in the appearance of magnetization reversal intervals with increase in Josephson to magnetic energy relation is found. The obtained results might be used in different fields of superconducting spintronics.

The structure of the exotic $^{8}$B nucleus is studied by means of elastic scattering, as well as its breakup on nuclear targets. We present microscopic calculations of the optical potentials (OPs) and cross sections of elastic scattering of $^{8}$B on $^{12}$C, $^{58}$Ni, and $^{208}$Pb targets at energies $20

Aspects of nuclear structure in alpha-conjugate nuclei have long been associated with alpha clustering, including the existence of superdeformed bands. In this paper, an alpha-particle inelastic scattering experiment investigating the location of $0^+$ states in $^{28}$Si is reported in an attempt to locate possible cluster states. The results are compared to a semi-microscopic model which shows good agreement with the data, and supports the assignment of a newly discovered $0^+$ state as the band-head of a previously observed superdeformed band in $^{28}$Si, Comment: 6 figures, 8 pages, updated to fix broken figure placement, updated again to fix a couple of typos; final update

The density distributions of $^{10}$Be and $^{11}$Be nuclei obtained within the quantum Monte Carlo (QMC) model and the generator coordinate method (GCM) are used to calculate the microscopic optical potentials (OPs) and cross sections of elastic scattering of these nuclei on protons and $^{12}$C at energies $E<100$ MeV/nucleon. The real part of the OP is calculated using the folding model with the exchange terms included, while the imaginary part of the OP that reproduces the phase of scattering is obtained in the high-energy approximation (HEA). In this hybrid model of OP the free parameters are the depths of the real and imaginary parts obtained by fitting the experimental data. The well known energy dependence of the volume integrals is used as a physical constraint to resolve the ambiguities of the parameter values. The role of the spin-orbit potential and the surface contribution to the OP is studied for an adequate description of available experimental elastic scattering cross section data. Also, the cluster model, in which $^{11}$Be consists of a $n$-halo and the $^{10}$Be core, is adopted. Within the latter, the breakup cross sections of $^{11}$Be nucleus on $^{9}$Be, $^{93}$Nb, $^{181}$Ta, and $^{238}$U targets and momentum distributions of $^{10}$Be fragments are calculated and compared with the existing experimental data., Comment: 14 pages, 10 figures, 3 tables, accepted for publication in Physical Review C

A computer simulation of the formation of photoexcited electrons in water is performed within the framework of a dynamic model. The obtained results are discussed in comparison with experimental data and theoretical estimates., Comment: 6 pages, 8 figures

The reaction mechanism of pre-equilibrium proton-induced $\alpha $-particle emission from 93Nb at an incident energy of 100 MeV was investigated with polarized projectiles. A formalism based on the statistical multistep direct emission model of Feshbach, Kerman and Koonin was found to give a reasonably good reproduction of cross section and analyzing power angular distributions at various emission energies. Existing experimental distributions for the same reaction at an incident energy of 65 MeV were also analyzed with the same model. The incident-energy variation from 65 MeV up to 160 MeV was found to be consistent with the predictions of the basic model. However, whereas knockout of an $\alpha $ cluster is the dominant reaction mechanism in the final stage at the lowest- and highest incident energies, at 100 MeV a pickup process competes with comparable intensity in yield., Comment: 11 pages, 5 figures

In the paper, the results of analysis of elastic scattering and breakup processes in interactions of the $^{11}$Li nucleus with protons are presented. The hybrid model of the microscopic optical potential (OP) is applied. This OP includes the single-folding real part, while its imaginary part is derived within the high-energy approximation (HEA) theory. For the $^{11}$Li$+p$ elastic scattering, the microscopic large-scale shell model (LSSM) density of $^{11}$Li is used. The depths of the real and imaginary parts of OP are fitted to the elastic scattering data at 62, 68.4, and 75 MeV/nucleon, being simultaneously adjusted to reproduce the true energy dependence of the corresponding volume integrals. The role of the spin-orbit potential is studied and predictions for the total reaction cross sections are made. Also, the cluster model, in which $^{11}$Li consists of $2n$-halo and the $^{9}$Li core having its own LSSM form of density, is adopted. The respective microscopic proton-cluster OP's are calculated and folded with the density probability of the relative motion of both clusters to get the whole $^{11}$Li$+p$ optical potential. The breakup cross sections of $^{11}$Li at 62 MeV/nucleon and momentum distributions of the cluster fragments are calculated. An analysis of the single-particle density of $^{11}$Li within the same cluster model accounting for the possible geometric forms of the halo-cluster density distribution is performed., Comment: 16 pages, 14 figures, accepted for publication in Physical Review C

Analytic calculation are presented of the contribution to the anomalous magnetic moment of a muon from the channels of annihilation of an electron-positron pair to a pair of charged pi-mesons with radiative correction connected with the final state, as well as corrections to the lowest order kernel. The result with point-like pi-meson assumptions is $a_{point}=a_{point}^{(1)}+\Delta a_{point}$, $a_{point}^{(1)}=7.0866 \cdot 10^{-9}; \Delta a_{point}= -2.4 \cdot 10^{-10} .$ Taking into account the pion form factor in the frames of the Nambu-Jona-Lasinio (NJL) approach leads to $a_{NJL}=a_{NJL}^{(1)}+\Delta a_{NJL}$, $a_{NJL}^{(1)}= 5.48\cdot 10^{-8}; \Delta a_{NJL}=-3.43\cdot 10^{-9}$., Comment: 15 pages, 2 figure

Analysis is performed of calculations of the elastic scattering differential cross sections of pions on the $^{28}$Si, $^{40}$Ca, $^{58}$Ni and $^{208}$Pb nuclei at energies from 130 to 290 MeV basing on the microscopic optical potential (OP) constructed as an optical limit of a Glauber theory. Such an OP is defined by the corresponding target nucleus density distribution function and by the elementary $\pi N$ amplitude of scattering. The three (say, "in-medium") parameters of the $\pi N$ scattering amplitude: total cross section, the ratio of real to imaginary part of the forward $\pi N$ amplitude, and the slope parameter, were obtained by fitting them to the data on the respective pion-nucleus cross sections calculated by means of the corresponding relativistic wave equation with the above OP. A difference is discussed between the best-fit "in-medium" parameters and the "free" parameters of the $\pi N$ scattering amplitudes known from the experimental data on scattering of pions on free nucleons., Comment: 10 pages, 1 table, 7 figures. To be published in Proceedings of the International Workshop on Nuclear Theory (Rila Mountain, Bulgaria, June 2012)

The fluxon solutions of a boundary problem for the sine-Gordon equation (SGE) are investigated numerically in dependence on the boundary conditions. Interconnection between fluxon and constant solutions is analyzed. Numerical results are discussed in context of the long Josephson junction model., Comment: 6 pages, 7 figures, Int. Conference MMCP-2011, July, 2011

We consider the undamped nonlinear Schr\"odinger equation driven by a periodic external force. Classes of travelling solitons and multisoliton complexes are obtained by the numerical continuation in the parameter space. Two previously known stationary solitons and two newly found localised solutions are used as the starting points for the continuation. We show that there are two families of stable solitons: one family is stable for sufficiently low velocities while solitons from the second family stabilise when travelling faster than a certain critical speed. The stable solitons of the former family can also form stably travelling bound states., Comment: 13 pages, 8 figures

Stationary and oscillatory bound states, or complexes, of the damped-driven solitons are numerically path-followed in the parameter space. We compile a chart of the two-soliton attractors, complementing the one-soliton attractor chart., Comment: 12 pages, 7 figures

Time-periodic solitons of the parametrically driven damped nonlinear Schr\"odinger equation are obtained as solutions of the boundary-value problem on a two-dimensional spatiotemporal domain. We follow the transformation of the periodic solitons as the strength of the driver is varied. The resulting bifurcation diagrams provide a natural explanation for the overall form and details of the attractor chart compiled previously via direct numerical simulations. In particular, the diagrams confirm the occurrence of the period-doubling transition to temporal chaos for small values of dissipation and the absence of such transitions for larger dampings. This difference in the soliton's response to the increasing driving strength can be traced to the difference in the radiation frequencies in the two cases. Finally, we relate the soliton's temporal chaos to the homoclinic bifurcation., Comment: 13 pages, 7 figures

The breakup cross sections in the reaction $^6$He+$^{12}$C are calculated at about 40 MeV/nucleon using the high-energy approximation (HEA) and with the help of microscopic optical potentials (OP) of interaction with the target nucleus $^{12}$C of the projectile nucleus fragments $^4$He and 2n. Considering the di-neutron $h$=2n as a single particle the relative motion $h\alpha$ wave function is estimated so that to explain both the separation energy of $h$ in $^6$He and the rms radius of the latter. The stripping and absorbtion total cross sections are calculated and their sum is compared with the total reaction cross section obtained within a double-folding microscopic OP for the $^6$He+$^{12}$C scattering. It is concluded that the breakup cross sections contribute in about 50% of the total reaction cross section., Comment: 9 pages, 4 figures, 2 tables; to be published in Proceedings of the 29th International Workshop on Nuclear Theory (June 2010, Rila Mountains, Bulgaria)

We study the long Josephson junction (LJJ) model which takes into account the second harmonic of the Fourier expansion of Josephson current. The dependence of the static magnetic flux distributions on parameters of the model are investigated numerically. Stability of the static solutions is checked by the sign of the smallest eigenvalue of the associated Sturm-Liouville problem. New solutions which do not exist in the traditional model, have been found. Investigation of the influence of second harmonic on the stability of magnetic flux distributions for main solutions is performed., Comment: 4 pages, 6 figures, to be published in Proc. of Dubna-Nano2010, July 5-10, 2010, Russia

The $^6$He+$^{12}$C elastic scattering data at beam energies of 3, 38.3 and 41.6 MeV/nucleon are studied utilizing the microscopic optical potentials obtained by a double-folding procedure and also by using those inherent in the high-energy approximation. The calculated optical potentials are based on the neutron and proton density distributions of colliding nuclei established in an appropriate model for $^6$He and obtained from the electron scattering form factors for $^{12}$C. The depths of the real and imaginary parts of the microscopic optical potentials are considered as fitting parameters. At low energy the volume optical potentials reproduce sufficiently well the experimental data. At higher energies, generally, additional surface terms having form of a derivative of the imaginary part of the microscopic optical potential are needed. The problem of ambiguity of adjusted optical potentials is resolved requiring the respective volume integrals to obey the determined dependence on the collision energy. Estimations of the Pauli blocking effects on the optical potentials and cross sections are also given and discussed. Conclusions on the role of the aforesaid effects and on the mechanism of the considered processes are made., Comment: 12 pages, 9 figures, accepted for publication in Physical Review C

We study the long Josephson junction (LJJ) model which takes into account the second harmonic of the Fourier expansion of Josephson current. The sign of second harmonic is important for many physical applications. The influence of the sign and value of the second harmonic on the magnetic flux distributions is investigated. At each step of numerical continuation in parameters of the model, the corresponding nonlinear boundary problem is solved on the basis of the continuous analog of Newton's method with the 4th order Numerov discretization scheme. New solutions which do not exist in the traditional model have been found. The influence of the second harmonic on stability of magnetic flux distributions for main solutions is investigated., Comment: 7 pages, 4 figures, to be published in Proc. of FDM10, June 28 - July 2, 2010, Lozenetz, Bulgaria

The decrease of the barrier transparency in superconductor-insulator-superconductor (SIS) Josephson junctions leads to the deviations of the current-phase relation from the sinusoidal form. The sign of second harmonics is important for many applications, in particular in junctions with a more complex structure like SNINS or SFIFS, where N is a normal metal and F is a weak metallic ferromagnet. In our work we study the static magnetic flux distributions in long Josephson junctions taking into account the higher harmonics in the Fourier-decomposition of the Josephson current. Stability analysis is based on numerical solution of a spectral Sturm-Liouville problem formulated for each distribution. In this approach the nullification of the minimal eigenvalue of this problem indicates a bifurcation point in one of parameters. At each step of numerical continuation in parameters of the model, the corresponding nonlinear boundary problem is solved on the basis of the continuous analog of Newton's method. The solutions which do not exist in the traditional model have been found. The influence of second harmonic on stability of magnetic flux distributions for main solutions is investigated.

An approach to calculate microscopic optical potential (OP) with the real part obtained by a folding procedure and with the imaginary part inherent in the high-energy approximation (HEA) is applied to study the $^8$He+p elastic scattering data at energies of tens of MeV/nucleon (MeV/N). The neutron and proton density distributions obtained in different models for $^{8}$He are utilized in the calculations of the differential cross sections. The role of the spin-orbit potential is studied. Comparison of the calculations with the available experimental data on the elastic scattering differential cross sections at beam energies of 15.7, 26.25, 32, 66 and 73 MeV/N is performed. The problem of the ambiguities of the depths of each component of the optical potential is considered by means of the imposed physical criterion related to the known behavior of the volume integrals as functions of the incident energy. It is shown also that the role of the surface absorption is rather important, in particular for the lowest incident energies (e.g., 15.7 and 26.25 MeV/nucleon)., Comment: 11 pages, 7 figures, accepted for publication in Physical Review C

Calculations are made of the $K^{+}+^{12}$C, $^{40}$Ca differential elastic scattering cross sections at the beam momenta 0.635, 0.715, and 0.8 GeV/c. To this end the microscopic optical potential derived in the high-energy approximation was used where existing data on the kaon-nucleon amplitude and on the point-like density distributions of target-nuclei were utilized. The effect of different methods of relativization was studied and shown to play an important role. A good agreement with the experimental data on differential elastic cross sections was obtained., Comment: 5 pages; 3 figures; Talk given at XIX Int. Baldin Seminar "Relativistic Nuclear Physics and Quantum Chromodynamics", Sept. 29-Oct.4, Dubna, 2008

Calculations of microscopic optical potentials (OP's) (their real and imaginary parts) are performed to analyze the $^6$He+p elastic scattering data at a few tens of MeV/nucleon (MeV/N). The OP's and the cross sections are calculated using three model densities of $^6$He. Effects of the regularization of the NN forces and their dependence on nuclear density are investigated. Also, the role of the spin-orbit terms and of the non-linearity in the calculations of the OP's, as well as effects of their renormalization are studied. The sensitivity of the cross sections to the nuclear densities was tested and one of them that gives a better agreement with the data was chosen., Comment: 13 pages, 11 figures, to be published in Eur. Phys. J. A

In the density distribution of a deformed target-nucleus, the spherical $\lambda = 0$ and the deformed $\lambda = 2$ parts were considered. On this basis, the corresponding potential parts $U_0$ and $U^{(2)}_{int}$ of a double -folding microscopic nucleus-nucleus optical potential are obtained. Then, for these potentials and by using the coupled-channel technique (ECIS), the elastic and inelastic amplitudes are calculated for $^{17}O$ heavy ion scattering on $2^{+}$ collective excited state of various target nuclei. Besides, the same cross-sections are calculated in the frame of an adiabatic approach of the eikonal approximation, where the inelastic amplitude is the linear function of $U^{(2)}_{int}$. Both the obtained results are compared with the experimental data, and also discuss their efficiency in predicting the deformation parameters of nuclei., Comment: 9 pages, 4 figures, 1 table

We study interactions between the dark solitons of the parametrically driven nonlinear Schr\"odinger equation, Eq.(\ref{NLS}). When the driving strength, $h$, is below $\sqrt{\gamma^2 +1/9}$, two well-separated N\'eel walls may repel or attract. They repel if their initial separation $2z(0)$ is larger than the distance $2z_u$ between the constituents in the unstable stationary complex of two walls. They attract and annihilate if $2z(0)$ is smaller than $2z_u$. Two N\'eel walls with $h$ lying between $\sqrt{\gamma^2 + 1/9}$ and a threshold driving strength $h_{sn}$ attract for $2z(0)<2z_u$ and evolve into a stable stationary bound state for $2z(0)>2z_u$. Finally, the N\'eel walls with $h$ greater than $h_{sn}$ attract and annihilate -- irrespective of their initial separation. Two Bloch walls of opposite chiralities attract, while Bloch walls of like chiralities repel -- except near the critical driving strength, where the difference between the like-handed and oppositely-handed walls becomes negligible. In this limit, similarly-handed walls at large separations repel while those placed at shorter distances may start moving in the same direction or transmute into an oppositely-handed pair and attract. The collision of two Bloch walls or two nondissipative N\'eel walls typically produces a quiescent or moving breather., Comment: 46 pages, 23 figures. To appear in Phys Rev E. A reference added

The existing and some preliminary experimental data on the total cross sections of the $^{4,6}$He, $^{6,7}$Li +$^{28}$Si reactions at energies E=5-50 A MeV are demonstrated. The data on $^{6}$Li,$^{6}$He+$^{28}$Si are analyzed in the framework of the microscopic optical potential with real and imaginary parts obtained with a help of the double-folding procedure and by using the current models of densities of the projectile nuclei. Besides, the microscopic double-folding Coulomb potential is calculated and its effect on cross sections is compared with that when one applies the traditional Coulomb potential of the uniform charge distribution. The semi-microscopic potentials are constructed from both the renormalized microscopic potentials and their derivatives to take into account collective motion effect and to improve an agreement with experimental data., Comment: 8 pages; 7 figures; submitted to Proceedings of the International Symposium on Exotic Nuclei "EXON-2006" (Khanty-Mansiysk, Russia, 17-22 July 2006)

We consider the charge-odd correlations (COC) in cross sections of processes of production of charged particles. The cases of a muonic pair and pion systems $\pi^{+}\pi^{-},\pi^{+}\pi^{-}\pi^{0}$ are considered in detail for electron-proton or photon-proton collisions in the proton fragmentation region kinematics. COC arise from interference of amplitudes which describe the different mechanisms of charged leptons (pions) creation. One of them corresponds to production of particles in the charge-odd state (one virtual photon or vector meson annihilation to this system of particles) and the other corresponds to the charge-even state of produced particles (creation by two photons). COC for muon-antimuon pair creation have a pure QED nature and can be considered as a normalization process. The processes with pion production are sensitive to some characteristics of proton wave functions and, besides, can be used for checking the anomalous and normal parts of the effective pionic lagrangian. Three electromagnetic currents operator matrix element can be measured in photon-proton interactions with lepton pair production. For this aim a charge-odd combination of cross sections can be constructed as a conversion of leptonic 3-rank tensor with hadronic ones. These experiments can be considered as an alternative to deep virtual Compton scattering., Comment: 13 pages, 3 figures

The (semi-)microscopic double-folding nucleus-nucleus optical potentials are suggested for consideration of inelastic scattering with excitation of collective nuclear states by using the adiabatic approach and the elastic scattering amplitude in the high-energy approximation. The analytical expression for inelastic scattering amplitude is obtained keeping the first order terms in the deformation parameter of a potential. Calculations of inelastic cross sections for the $^{17}$O heavy ions scattered on different nuclei at about hundred Mev/nucleon are made, and the acceptable qualitative agreement with the experimental data is obtained without introducing free parameters. The prospect of the method for further applications is discussed., Comment: 9 pages, 3 figures, 1 table, submitted to "Partices and Nuclei, Letters"

A phenomenological optical potential is generalized to include the Coulomb and nuclear interactions caused by the dynamical deformation of its surface. In the high-energy approach analytical expressions for elastic and inelastic scattering amplitudes are obtained where all the orders in the deformation parameters are included. The multistep effect of the 2$^+$ rotational state excitation on elastic scattering is analyzed. Calculations of inelastic cross sections for the $^{17}$O ions scattered on different nuclei at about hundred Mev/nucleon are compared with experimental data, and important role of the Coulomb excitation is established., Comment: 9 pages; 3 figures. Submitted to the Physics of Atomic Nuclei

Small angle neutron scattering (SANS) on the unilamellar vesicle populations (diameter 500 and 1000 angstrom) was used to characterize lipid vesicles from dimyristoylphosphatidylcholine (DMPC) at three phases (gel, ripple, and liquid). Parameters of vesicle populations and internal structure of the DMPC bilayer were characterized on the basis of the Separated Form Factor (SFF) model. Parameters of the internal bilayer structure (thickness of the membrane and the hydrophobic core, hydration, and surface area of lipid molecule) were determined on the basis of the Hydrophobic-Hydrophilic (HH) approximation of neutron scattering length density across the bilayer r(x) and of the Step Function (SF) approximation of r(x). It was demonstrated in frame of HH approximation that DMPC membrane thickness in liquid phase (T=30 degrees) depends on the membrane curvature. The dependence of the DMPC membrane thickness on temperature was restored from the SANS experiment., Comment: 18 pages; 7 figures; 5 tables. Submitted to the European Biophysics Journal. Available as JINR Preprint E14-2005-93 (Dubna, Russia) 2005

Results of charge form factors calculations for several unstable neutron-rich isotopes of light, medium and heavy nuclei (He, Li, Ni, Kr, Sn) are presented and compared to those of stable isotopes in the same isotopic chain. For the lighter isotopes (He and Li) the proton and neutron densities are obtained within a microscopic large-scale shell-model, while for heavier ones Ni, Kr and Sn the densities are calculated in deformed self-consistent mean-field Skyrme HF+BCS method. We also compare proton densities to matter densities together with their rms radii and diffuseness parameter values. Whenever possible comparison of form factors, densities and rms radii with available experimental data is also performed. Calculations of form factors are carried out both in plane wave Born approximation (PWBA) and in distorted wave Born approximation (DWBA). These form factors are suggested as predictions for the future experiments on the electron-radioactive beam colliders where the effect of the neutron halo or skin on the proton distributions in exotic nuclei is planned to be studied and thereby the various theoretical models of exotic nuclei will be tested., Comment: 26 pages, 11 figures, 3 tables, accepted for publication in Phys. Rev. C

Three types of microscopic nucleus-nucleus optical potentials are constructed using three patterns for their real and imaginary parts. Two of these patterns are the real $V^H$ and imaginary $W^H$ parts of the potential which reproduces the high-energy amplitude of scattering in the microscopic Glauber-Sitenko theory. Another template $V^{DF}$ is calculated within the standard double-folding model with the exchange term included. For either of the three tested potentials, the contribution of real and imaginary patterns is adjusted by introducing two fitted factors. An acceptable agreement with the experimental data on elastic differential cross-sections was obtained for scattering the $^{16, 17}$O heavy-ions at about hundred Mev/nucleon on different target-nuclei. The relativization effect is also studied and found that, to somewhat, it improves the agreement with experimental data., Comment: 11 pages; 8 figures. The talk given at the XVII Int. Baldin Seminar on High Energy Physics Problems "Relativistic Nuclear Physics & Quantum Chromodynamics", September 27 - October 2, 2004, Dubna, Russia

On the basis of the separated form-factors model, parameters of the polydispersed unilamellar DMPC vesicle population are analyzed. The neutron scattering length density across the membrane is simulated on the basis of fluctuated model of lipid bilayer. The hydration of vesicle is described by sigmoid distribution function of the water molecules. The results of fitting of the experimental data obtained at the small angle spectrometer SANS-I, PSI (Switzerland) are: average vesicle radius 272 angstrom, polydispersity of the radius 27%, membrane thickness 50.6 angstrom, thickness of hydrocarbon chain region 21.4 angstrom, number of water molecules located per lipid molecule 13, and DMPC surface area 59. The calculated water distribution function across the bilayer directly explains why lipid membrane is easy penetrated by water molecules., Comment: 10 pages, 2 figures, 1 table; to be published in Crystallography Reports

On the basis of the separated form-factor model, a code for fitting the small-angle neutron scattering spectra of the polydispersed vesicle population has been developed. Vesicle and membrane bilayer parameters are analyzed for various hierarchical models of the neutron scattering length density across the membrane. It is shown that hydration of vesicle can be described by a linear distribution function of water molecules. For the first time, the average radius and polydispersity of the vesicle population, thickness of the membrane bilayer, thickness of hydrophobic and hydrophilic parts of bilayer, and water distribution function have been calculated from the SANS experiment, without additional methods such as dynamic light scattering or freeze-fracture electron microscopy. The results, obtained at two different spectrometers, are discussed. The appropriate conditions of the SANS experiment on vesicles are formulated as a necessity to collect the SANS curve in the region of scattering vectors from qmin=0.0033 1/angstrom to qmax=0.56 1/angstrom., Comment: 18 pages, 3 figures, 2 tables; to be published in JCMASE