Saint-petersburg state university russian academy of sciences joint institute for nuclear research
ENERGY CHARACTERISTICS OF RELATIVISTIC
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- GAMMA-DECAY TRANSITION RATES AND CONFIGURATION SPLITTING IN THE TWO-GROUP SHELL MODEL
- ON THE PROPERTIES OF N =50 EVEN-EVEN ISOTONES FROM 78 Ni TO 100 Sn
- PROBABILITIES OF MAGNETIC TOROIDAL MONO-FIELDS IN THE NON-STATIONARY PROCESSES OF RADIOACTIVE LUTETIUM OXIDE
- STUDY OF PENETRATION EFFECTS IN 69.7 keV M 1-TRANSITION IN 153 Eu
- DAMPING OF DEEP-HOLE STATES IN MEDIUM-HEAVY-MASS SPHERICAL NUCLEI
- ASYMPTOTIC MODELS FOR STUDYING KINETICS OF FORMATION OF COMPACT OBJECTS WITH STRONG INTERNAL BONDS
- BOUND FERMION STATES IN THE FIELD OF THE SOLITON OF THE NONLINEAR O (3) σ -MODEL
- QUADRUPOLE DEFORMATION PARAMETER OF EVEN-EVEN NUCLEI IN THE RANGE OF 58 ≤ A ≤ 250 AND THE COUPLED CHANNEL OPTICAL MODEL
- PRODUCTION OF STRANGE PARTICLES IN THE FRAMEWORK OF MULTI-POMERON EXCHANGE MODEL
ENERGY CHARACTERISTICS OF RELATIVISTIC CHARGED PARTICLE IN A CIRCULARLY POLARIZED PHASE-FREQUENCY MODULATED ELECTROMAGNETIC WAVE AND IN THE CONSTANT MAGNETIC FIELD Akintsov N.S., Kopytov G.F., Martynov A.A., Chavlikov V.I., Voinov R.A. Kuban State University, Krasnodar, Russia E-mail: akintsov777@mail.ru We consider the dynamics of a relativistic electron in a strong phase- frequency modulated electromagnetic field of circular polarization and in constant magnetic field. The interaction of charged particles with ultrashort femtosecond laser pulses with intensities of radiation to 10 22 W/cm 2 is one of the main areas of laser physics at the moment. In this paper, we assumed that a plane monochromatic electromagnetic wave modulated by phase-frequency [1]. We obtained the following result for the average kinetic energy of the particle over the period of vibration: 2 2 2 4 2 2 8 . 32 1 N n n n n N S N mc mc h h Z (1) where 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 5 2 / 1 , 1 1 2 , , . 4 , , 1 3 n n n N n n n n n N J n N n S n q b q h Z T I n T m c m c (2) Here 2 / 8 I cb – the intensity of a circularly polarized electromagnetic wave; 2 / с – wavelength; 2 mc – the rest energy of a charged particle; q > 0 the absolute value of the electron charge; – frequency ratio of с and and besides 0;1 ; / ; / m – modulation index equal to the ratio of frequency deviation to the frequency of the modulating wave; – frequency modulation; n J – the n-th Bessel function. In the absence of phase-frequency modulation and constant magnetic field, we obtain formula for the case of circular polarization [2]. The resulting formula for contains an explicit dependence on the initial data: the amplitude of the electromagnetic wave, frequency carrier wave and modulation frequency, intensity and polarization. It allows to carry out practical calculations. 1. G.F.Kopytov, S.S.Oksuzyan, V.B.Tlyachev. K voprosu o harakteristikah izlucheniya elektrona v modulirovannom elektromagnitnom pole. Red. Zh. "Izv. Vuzov. Fizika" - Tomsk, 1987. P.15. Dep. VINITI 14.09.85, № 7353 2. S.N.Andreev, V.PMakarov, A.A.Rukhadze // Quantum Electronics. 2009. №1(39), P.68 . 161 GAMMA-DECAY TRANSITION RATES AND CONFIGURATION SPLITTING IN THE TWO-GROUP SHELL MODEL Isakov V.I. National Research Center “Kurchatov Institute”, Moscow, Russia Petersburg Nuclear Physics Institute, Gatchina E-mail: visakov@thd.pnpi.spb.ru In our previous paper [1] we considered intershell beta- and gamma-decay transition rates between the two-group configurations, specifically between the configurations `1 2 1 1 1 1 2 2 2 2 ( ) ( ) n n j s J j s J and 1 2 1 1 ' ' ' ' ' ' 1 1 1 1 2 2 2 2 ( ), ( ) n n j s J j s J . Here, we consider gamma-transitions within the configuration 1 2 1 2 , , n n j j as well as configuration splitting conditioned by the two-body interaction. For this aim, we use the formalism of the two-group fractional parentage expansions, that takes account of antisymmetrization, and the Racah algebra. The obtained formulas may be strongly simplified in case of odd-odd nuclei, if we consider multiparticle states with lowest values of seniorities. In this way, we obtain simple analytical expressions for transition rates, as well as for electric quadrupole and magnetic dipole moments. The formulas are applied for description of experimental data in nuclei close to 90 Zr. We obtained a good agreement with the experiment over the data on the E2 transition rates, values of quadrupole and dipole moments, as well as over data on energy spectra of odd- odd isotones with N = 51. When calculating energy spectra, we employed effective interaction used by us before [2, 3]. 1. V.I.Isakov // Phys. Atom. Nucl. 2014. V.77. P.569. 2. V.I.Isakov // Phys. Atom. Nucl. 2013. V.76. P.828. 3. V.I.Isakov // Phys. Atom. Nucl. 2010. V.73. P.1516. 162 ON THE PROPERTIES OF N=50 EVEN-EVEN ISOTONES FROM 78 Ni TO 100 Sn Isakov V.I. National Research Center “Kurchatov Institute”, Moscow, Russia; Petersburg Nuclear Physics Institute, Gatchina, Russia E-mail: visakov@thd.pnpi.spb.ru By now, basic efforts in experimental nuclear physics are concentrated on investigation of nuclei far from the stability line. In papers [1, 2], we performed calculations of basic properties of nuclei in the long chains of isotopes of Ni (Z=28), from proton excess 48 Ni up to neutron-excess 78 Ni, and of isotopes of Sn (Z=50), from 100 Sn to 132 Sn. Here, we study the chain of N=50 isotones, from neutron-excess 78 Ni, up to proton-excess 100 Sn. We calculate binding and one-nucleon separation energies, density distributions of protons and neutrons, root-mean-square radii, as well as excitation energies and transition rates. Below, we show excitation energies and corresponding transition rates of the lowest quadrupole states in even-even nuclei with N=50. Fig. 1. Energies of the 2 1 levels and transition rates in the sequence of N=50 isotones, from 78 Ni to 100 Sn. 1. V.I.Isakov // Phys. Atom. Nucl. 2010. V.73. P.1516. 2. V.I.Isakov // Phys. Atom. Nucl. 2013. V.76. P.828. 163 PROBABILITIES OF MAGNETIC TOROIDAL MONO-FIELDS IN THE NON-STATIONARY PROCESSES OF RADIOACTIVE LUTETIUM OXIDE Kartashov V.М., Talpakova К.А., Aldiyarov N.U. Institute of Nuclear Physics, Almaty, Kazakhstan E-mail: kartv@inp.kz The issues of magnetism, its nature have been recently discussed in large extent by Ginzburg V.A. [1] and Kopaev Yu.V. [2]. In contrast to us, they reviewed not the radioactive materials of other chemical content, but as we are they extremely focused on the toroidal polarization of the discussed material. In general, our approaches for solving the problems are simply not compatible and our decision to consider and provide other theoretical interpretations than those considered by them in their problems is quite objectively justified. The methods of nuclear electron spectroscopy are quite effective in solving the various complex problems. It is interesting, that the super-strong magnetic field, observed in the process of toroidal polarization, providing the line splitting of the M and N - shells of nuclear states, agitates the assumption relating to the features of toroidal magnetic mono-fields formation, which different versions have not recently deny the various theories. It is undisputable, that the serious explanation for the observed experimental data should lead to the important theoretical conclusions, and possibly to the major proposals to consider some options of their practical use based on them. 1. V.L.Ginzburg // UFN. 2001. V.171. №10. P.1091. 2. Yu.V.Kopaev // UFN. 2009. V.179. №11. P.1175. 164 STUDY OF PENETRATION EFFECTS IN 69.7 keV M1-TRANSITION IN 153 Eu Drapey S.S., Zheltonozhsky V.A., Savrasov A.N., Khomenkov V.P. Institute for Nuclear Research, Kyiv, Ukraine E-mail: khomenkov@kinr.kiev.ua Study of penetration effects in M1-transitions gives a unique opportunity to estimate the value and the sign of spin-multipole force. Note, that except for E1-transitions this is the only way to obtain such an information for other multipolarities. Penetration effects for M1-transitions are described by the expression K exp = K tab (1 + B 1 + B 2 2 ), where are table and experimental values of internal conversion coefficients on K-shell, B i are electronic parameters given in corresponding tables. Penetration effects contribution is usually about few percents, so K exp should be measured with the accuracy of (1–2)%. We performed measurement of K of 69.7 keV transition by comparison of intensity of its -rays (I ) and characteristic radiation (I Kx ) accompanying internal conversion process K = I Kx / (I ω K ), where ω K is fluorescence yield. Measurements were performed with 153 Gd source 153 Gd (T 1/2 = 241.6 days). The source was produced at KINR research reactor. Via electron capture 153 Gd is decayed on excited states of 153 Eu. The state with energy 173 keV (I π = 5/2 + ) is decayed by inhibited M1-transition (F W =4.5) with energy 69.7 keV. We carried out the measurement using Ge-spectrometer with 500 eV resolution in 70 keV energy region. Intensity of triple summation peaks (I 103 + I Kx + I Kx ) and (I 103 + I 69 + I Kx ) was measured. From these data K exp = 4.31±0.09 value has been determined. Statistical error was about (0.3–0.5)%. The accuracy of relative registration efficiency is within 0.5% due to proximity of K X -radiation and 69.7 keV. However, because of large (up to 30%) contribution of accidental coincidences the total error was found to be (1.5–2)%. The table value is K tab = 4.51 taking into account 1.9% admixture of E2-component. From these data we found penetration parameter value = –1.9 ± 1.1 corresponding to penetration effects in 69.7 keV transition of 153 Eu. Obtained results are under discussion. 165 DAMPING OF DEEP-HOLE STATES IN MEDIUM-HEAVY-MASS SPHERICAL NUCLEI Kolomiytsev G.V. 1 , Igashov S.Yu. 2 , Urin M.H. 1 1 National Research Nuclear University “MEPhI”, Moscow, Russia; 2 All-Russia Research Institute of Automatics, Moscow, Russia E-mail: flight160@gmail.com Experimentally found the anomalously large excitation energy and total width of deep-hole states in the 90 Zr and 208 Pb parent nuclei [1] motivates us to apply a recently reformulated single-quasiparticle dispersive optical-model (SQDOM) [2] to the description of these states. In most Hartree-Fock calculations exploited different versions of Skyrme-type forces the energy of 1s 1/2 -states in 208 Pb is strongly underestimated [3]. The same conclusion is obtained with the use of phenomenological partially self-consistent mean-field exploited in [2]. Starting from this mean field, we apply the dispersive relationship of [2] to evaluate an energy-dependent addition to the mean field via an energy-dependent imaginary part of the optical-model potential. The parameters of this part are adjusted to reproduce via an iterative procedure the observable total width and excitation energy of a number of deep-hole states. Such a procedure, allowing us to describe at least qualitatively the deep-hole states in the 90 Zr and 208 Pb parent nuclei, demonstrate abilities of the SQDOM in phenomenological description of the spreading effect on properties of high- energy single-quasiparticle excitations in medium-heavy-mass spherical nuclei. This work is partially supported by RFBR (grant No. 15-02-08007a). 1. A.A.Vorobyov et al. // Phys. Atom. Nucl. 1995. V.58. P.1817. 2. G.V.Kolomiytsev, S.Yu.Igashov, M.H.Urin // Phys. Atom. Nucl. 2014. V.77. P.1105. 3. S.Shlomo. Private communication. 166 ASYMPTOTIC MODELS FOR STUDYING KINETICS OF FORMATION OF COMPACT OBJECTS WITH STRONG INTERNAL BONDS Lin E.E. Russian Federal Nuclear Center All-Russia Research Institute of Experimental Physics, Sarov, Russia E-mail: e.e.lin@ifv.vniief.ru An asymptotic method [1] has been developed for investigation of kinetics of formation of compact objects with strong internal bonds. The method is based on the uncertainty relation for a coordinate and a momentum in space of sizes of objects (clusters) with strongly pronounced collective quantum properties resulted from exchange interactions of various physical nature determined by spatial scales of the processes under consideration. The proposed phenomenological approach has been developed by analogy with the all-known ideas about coherent states of quantum mechanical oscillator systems for which a product of coordinate and momentum uncertainties (dispersions) accepts the value, which is minimally possible within uncertainty relations. With such an approach the leading processes are oscillations of components that make up objects, mainly: collective nucleon oscillations in a nucleus and phonon excitations in a mesostructure crystal lattice. This allows us to consider formation and growth of subatomic and mesoscopic objects in the context of a single formalism. The proposed models adequately describe characteristics of formation processes of nuclear matter clusters as well as mesoscopic crystals having covalent and quasi-covalent bonds between atoms. 1. E.E.Lin // World Journal of Mechanics. 2014. V.4. P.170. 167 BOUND FERMION STATES IN THE FIELD OF THE SOLITON OF THE NONLINEAR O(3) σ -MODEL Loginov A.Yu. National Research Tomsk Polytechnic University, Tomsk, Russia E-mail: aloginov@tpu.ru The (2 + 1)-dimensional nonlinear O(3) σ-model whose n-field is coupled to the fermion field by the Yukawa interaction has been examined. The cases of the isosinglet and isodoublet fermion fields with respect to the internal symmetry group have been considered. It has been shown that bound states of the fermion in the n-field of the soliton [1] of the nonlinear O(3) σ-model exist for some variants of the Yukawa interaction. The absence of zeroth fermion modes in the n-field of the soliton has been established. The properties of the ground state of the fermion have been numerically studied. In particular, it has been shown that an increase in the spatial size of the soliton results in a decrease in the energy of the ground state. This leads to the instability of the soliton in a certain region of the parameters of the model. This work was supported by the Russian Foundation for Basic Research (grant № 15-02-00570-a). 1. A.A.Belavin, A.M.Polyakov // JETP Lett. 1975. V.22. P.245. 168 QUADRUPOLE DEFORMATION PARAMETER OF EVEN-EVEN NUCLEI IN THE RANGE OF 58 ≤ A ≤ 250 AND THE COUPLED CHANNEL OPTICAL MODEL Mordovskoy M.V., Surkova I.V. Institute for Nuclear Research, Russian Academy of Sciences, Moscow, Russia E-mail: mvmordovsk@mail.ru Earlier, we analyzed experimental data on the interaction of low energy neutrons (0.04–3.0 MeV) with even-even isotopes over a wide range of mass numbers with 58 ≤ A ≤ 246 in the context of the coupled channel optical model (CCOM). The aim of analyzing the neutron data for a large number of nuclei, differing considerably in their properties, is to obtain a uniform description of the whole set of the data, to find shell effects in neutron cross sections, and to search for nontraditional magic nuclei. Our consideration involved a variety of options of Woods-Saxon potential. The CCOM parameters for each nucleus were found from the best description of the considered data. The use of this approach allowed us to obtain a good description for even-even nuclei over a range 58 ≤ A ≤ 246 with common CCOM parameters [1]. For magic (both traditional and non-traditional) and non-spherical nuclei diffuseness parameter value was different from the average value of 0.65 fm. These deviations are well described by the behavior of the N p N n product, where N p and N n – number of valence protons and neutrons. The values of the quadrupole deformation parameters, determining the matrix elements of channel coupling in the CCOM, were chosen equal to values, which were obtained mainly from electromagnetic processes (e.g. [5]). However, experimental studies of inelastic scattering of protons and neutrons on near magic nuclei [3] show the difference in nuclear and electromagnetic parameters of deformation. At a neutron energy of several MeV a good phenomenological description of elastic scattering and total cross sections for deformed nuclei was obtained for values 2, substantially lower (~ 30%) than the values determined from Coulomb excitation (e.g. [4]). We attempted to obtain an optimal description for "ambiguous" nuclei in terms of a unified approach by changing the core values 2 , derived from data on electromagnetic processes, and analyze these changes in terms of NpNn systematic. 1. D.A.Zaikin, I.V.Surkova, M.V.Mordovskoy // Eur. Phys. J. A. 1999. V.5. P.53. 2. S.Raman, C.H.Malarkey et al. // Atom. Data. Nucl. Data Tabl. 1987. V.36. P.1. 3. G.Haouat // Second Intern. Symp. On Neutron Induced Reactions. Smolenice. 1979. 4. M.T.McEllistrem, R.E.Shamu, J.LachKar et al. // Phys.Rev. C. 1977. V.15. P.927. 169 PRODUCTION OF STRANGE PARTICLES IN THE FRAMEWORK OF MULTI-POMERON EXCHANGE MODEL Feofilov G.A., Kovalenko V.N., Puchkov A.M. Saint-Petersburg State University, St. Petersburg, Russia E-mail: putchkov@mail.ru We propose an extension of multi-pomeron exchange model [1–3] by accounting the production of strange particles. The model [1–3] describes consistently multiplicity, transverse momentum and their correlation in pp and ppbar collisions in a wide energy range (from ISR to LHC) by introducing string interaction in an effective way. The particles species differentiation is implemented according to Schwinger mechanism [4]. The results on strange particles yields, their transverse momentum and correlations are presented and compared to the experimental data. We discuss also the influence of higher resonances on these observables. The authors acknowledge Saint-Petersburg State University for a research grant 11.38.242.2015. 1. N.Armesto, D.Derkach, G.Feofilov // Phys. Atom. Nucl. 2008. V.71. P.2087. 2. E.Bodnia, D.Derkach, G.Feofilov, V.Kovalenko, A.Puchkov // PoS (QFTHEP 2013) 060 (2013). arXiv:1310.1627. 3. E.O.Bodnia, V.N.Kovalenko, A.M.Puchkov, G.A.Feofilov // AIP Conf. Proc. 2014. V.1606. P.273. arXiv:1401.7534. 4. J.Schwinger // Phys. Rev. 1951. V.82. P.664; T.S.Biro, H.B.Nielsen, J.Knoll // Nucl. Phys. B. 1984. V.245. P.449. |
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