Showing papers in "International Journal of Modern Physics E-nuclear Physics in 1994"
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TL;DR: In this paper, a generalization of the fundamental constraints on quantum mechanical diffusion coefficients which appear in the master equation for the damped quantum oscillator is presented; the Schrodinger, Heisenberg and Weyl-Wigner-Moyal representations of the Lindblad equation are given explicitly.
Abstract: The damping of the harmonic oscillator is studied in the framework of the Lindblad theory for open quantum systems. A generalization of the fundamental constraints on quantum mechanical diffusion coefficients which appear in the master equation for the damped quantum oscillator is presented; the Schrodinger, Heisenberg and Weyl-Wigner-Moyal representations of the Lindblad equation are given explicitly. On the basis of these representations it is shown that various master equations for the damped quantum oscillator used in the literature are particular cases of the Lindblad equation and that not all of these equations are satisfying the constraints on quantum mechanical diffusion coefficients. Analytical expressions for the first two moments of coordinate and momentum are obtained by using the characteristic function of the Lindblad master equation. The master equation is transformed into Fokker-Planck equations for quasiprobability distributions and a comparative study is made for the Glauber P representation, the antinormal ordering Q representation, and the Wigner W representation. The density matrix is represented via a generating function, which is obtained by solving a timedependent linear partial differential equation derived from the master equation. Illustrative examples for specific initial conditions of the density matrix are provided. The solution of the master equation in the Weyl-Wigner-Moyal representation is of Gaussian type if the initial form of the Wigner function is taken to be a Gaussian corresponding (for example) to a coherent wavefunction. The damped harmonic oscillator is applied for the description of the charge equilibration mode observed in deep inelastic reactions. For a system consisting of two harmonic oscillators the time dependence of expectation values, Wigner function and Weyl operator, are obtained and discussed. In addition models for the damping of the angular momentum are studied. Using this theory to the quantum tunneling through the nuclear barrier, besides Gamow’s transitions with energy conservation, additional transitions with energy loss are found. The tunneling spectrum is obtained as a function of the barrier characteristics. When this theory is used to the resonant atom-field interaction, new optical equations describing the coupling through the environment of the atomic observables are obtained. With these equations, some characteristics of the laser radiation absorption spectrum and optical bistability are described.
148 citations
TL;DR: A review of the current status of theoretical treatments of neutrino-nucleus reactions that are relevant to the detection of astrophysical neutrinos is given in this paper.
Abstract: This is a review of the current status of theoretical treatments of neutrino-nucleus reactions that are relevant to the detection of astrophysical neutrinos. Various nuclear physics aspects involved in the evaluation of the neutrino-nucleus reaction cross-sections are critically surveyed.
51 citations
TL;DR: In this paper, the residual p-n interaction in doubly odd deformed nuclei is examined in the framework of the unified model and extensive experimental information about the Gallagher-Moszkowski splitting energies and Newby shifts in the rare-earth and actinide regions is used to deduce empirical parameters.
Abstract: The residual p-n interaction in doubly odd deformed nuclei is examined in the framework of the unified model. Extensive experimental information about the Gallagher-Moszkowski splitting energies and Newby shifts in the rare-earth and actinide regions is used to deduce empirical parameters of the residual p-n interaction. Delta interaction and Gaussian-shape radial potential are assumed, Empirical p-n parameters are discussed and compared with previously deduced parameters. For the first time, errors in the parameters are estimated and special attention is paid to parameter significance.
24 citations
TL;DR: In this paper, cold fission of radioactive nuclei is studied in the super-asymmetric mass region of exotic cluster radioactivity, using the quantum-mechanical fragmentation theory (QMFT) based saddle-point fission (SPF) model for calculating the decay half-life times.
Abstract: Cold fission of radioactive nuclei is studied in the super-asymmetric mass region of exotic cluster radioactivity, using the quantum-mechanical fragmentation theory (QMFT) based saddle-point fission (SPF) model for calculating the decay half-life times. The calculations show that cold fission also prefers light fragments like 24–26Ne, 28,30Mg, 32,34,36Si, 37P 38S, 46Ar and 48,50Ca, some of which are observed in exotic cluster radioactivity. The predictions of the SPF model calculations are compared with the available exotic cluster-decay experimental data and the calculations based on the preformed-cluster model (PCM). The SPF model calculations show large disagreements with both the PCM and cluster-decay experimental data. For clusters of mass A2 46. Also, cold fission is found to be more probable than hot fission and a new fission mode (known as bimodel fission) is identified in the neighbourhood of the doubly magic fragment. Our calculations are made for 234U, 238Pu, 241Am and 252Cf.
24 citations
TL;DR: In this paper, the half-life values were measured to be 204±45 ps in 188Hg and ≤52 ps in 186Hg, respectively, and the corresponding values of ρ2(E0)×103, obtained from the partial half-lives, were and ≥32, respectively.
Abstract: A new picosecond lifetime measurement system developed at UNISOR was used to determine the half-life of the well-deformed levels in 188Hg and 186Hg. The half-life values were measured to be 204±45 ps in 188Hg and ≤52 ps in 186Hg. The corresponding values of ρ2(E0)×103, obtained from the partial half-lives, were and ≥32, respectively. Additionally, the half-lives of the levels were determined to be 141±31 ps in 188Hg and 48±27 ps in 186Hg.
21 citations
TL;DR: In this article, one-phonon states with Kπ = 0− and 1− were calculated within the RPA taking the isoscalar and isovector particle-hole and particle-particle octupole and isovctor particlehole dipole interactions into account.
Abstract: One-phonon states with Kπ=0− and 1− are calculated within the RPA taking the isoscalar and isovector particle-hole and particle-particle octupole and isovector particlehole dipole interactions into account. General equations of the Quasiparticle-Phonon Nuclear Model are modified. The energies and wave functions of the nonrotational states below 2.3 MeV in 160Gd calculated within this model are in good overall agreement with experimental data. The E1 transition rates in several doubly even well-deformed nuclei are calculated. The influence of the radial dependence of the dipole and octupole interactions on E1 and E3 transition probabilities is investigated. It is shown that the fragmentation of one-phonon states below 2.3 MeV weakly affects the E1 transition rates from 1− states to the ground state. The fragmentation of one- and two-phonon states strongly affect B(E1) values of the transitions from 1− states with energy above 2.5 MeV to the ground states and between excited states. The results of calculating the E1 transition rates are compared with the relevant experimental data.
13 citations
TL;DR: In this paper, the excitation function of α-induced reactions on 121Sb and 123Sb has been measured and the α-beam energy ranges from 55.0±0.5 MeV to 21.9±1.2 MeV.
Abstract: The excitation function of α-induced reactions on 121Sb and 123Sb has been measured. The α-beam energy ranges from 55.0±0.5 MeV to 21.9±1.2 MeV. In these experiments, the stacked foil activation technique was used. The reaction yield was measured by counting the gamma ray activity produced by the alpha-induced reactions. Results so obtained were compared with the calculations from the geometry-dependent hybrid (GDH) model. The assumption of initial exciton number n0=4 with n=2, p=2 and h=0 best satisfies the results measured in the present work. The model calculations were done using the ALICE/LIVERMORE-82 computer code. The pre-equilibrium fraction has also been calculated.
9 citations
TL;DR: In this article, the problems of dynamical instability and clustering in a breakup of excited nuclear systems are considered from the points of view of the soliton concept, and it is shown that the volume (spinodal) instability can be associated with nonlinear terms, and the surface (Rayleigh-Taylor type) instability, with the dispersion terms in the evolution equations.
Abstract: The problems of dynamical instability and clustering (stable fragments formation) in a breakup of excited nuclear systems are considered from the points of view of the soliton concept. It is shown that the volume (spinodal) instability can be associated with nonlinear terms, and the surface (Rayleigh-Taylor type) instability, with the dispersion terms in the evolution equations. Both instabilities may compensate each other and lead to stable solutions (solitons).
7 citations
TL;DR: In this paper, the deuteron-nucleus interaction has been studied in the approximation case, where the nuclear surface diffuseness is small compared with the nuclear radius.
Abstract: The deuteron-nucleus interaction has been studied in the approximation where the deuteron radius and the nuclear surface diffuseness are small compared with the nuclear radius. The closed formulae have been derived for the integrated cross-sections of different deuteron-nucleus interaction processes and for differential cross-sections of the deuteron elastic scattering and the deuteron inelastic scattering with excitation of the low lying vibrational states of nuclei. It is shown that the allowance for nuclear surface diffuseness substantially influences the values of the different deuteron-nucleus reaction cross-sections.
6 citations
TL;DR: In this article, the authors studied the σ-ω model for nuclear matter at finite temperature and density in the functional integral approach and presented various ways to calculate the grand partition function for free massive vector particles and showed how field theories of two mutually interacting fields can be alternatively formulated in terms of a theory containing one free field and a nonlocal self interaction of the other field.
Abstract: We study the σ-ω model for nuclear matter at finite temperature and density in the functional integral approach. Particular emphasis is put on the treatment of the degrees of freedom of the massive vector meson. Various ways to calculate the grand partition function for free massive vector particles are presented. Then we show how field theories of two mutually interacting fields can be alternatively formulated in terms of a theory containing one free field and a nonlocal self-interaction of the other field. For a perturbative expansion in powers of the coupling constant and in the mean-field approximation, this formulation gives the same results as the standard treatment, e.g., the loop-expansion scheme of the effective potential. However, in contrast to the latter, the mean-field approximation is now obtained in a very simple and physically obvious way which closely resembles the analogous derivation for statistical-mechanical systems. We apply our alternative formulation to the case of scalar and massive vector particles interacting with another field. Combining both cases and taking the nucleon field as the interaction partner, we finally arrive at the grand partition function for the σ-ω model in mean-field approximation.
6 citations
TL;DR: The spectra of the odd-A Ac isotopes from 215Ac through 231Ac (with 142 neutrons) serve as a sequence of examples for the application of a variety of nuclear models as discussed by the authors.
Abstract: The remarkable features of the spectra of the odd-A Ac isotopes from 215Ac (with 126 neutrons) through 231Ac (with 142 neutrons) serve as a sequence of examples for the application of a variety of nuclear models. As the shapes vary from spherical to spherical with strong octupole correlations to octupole-deformed, the corresponding symmetry breaking leads to increasingly complex spectra. The spectrum of 215Ac can be described in terms of the shell model configurations π(h9/2)4f7/2 and π(h9/2)4i13/2. However, even in this 126-neutron nucleus there is already a strongly enhanced E3 transition. The spectra of 217Ac and 219Ac can be interpreted in terms of the weak coupling of the h9/2 proton to the 216Ra and 218Ra cores, respectively. However, the existence of parity doublet bands (same spins but opposite parities) in 219At and the interleaving of positive and negative states in 218Ra clearly demonstrate the increasing importance of octupole deformation. Parity doublet bands are also present in the spectra of 221Ac. However, in both 219Ac and 221Ac the positive parity members of the parity doublets appear to cut off before reaching the low spin values expected from the negative parity bands. In 223Ac, 225Ac, and 227Ac the experimental spectra clearly show the existence of parity doublet bands built on the parity mixed configurations 5/2±(0.0; −0.2) and 3/2±(0.0; −0.3). The fact that the ordering of these two configurations changes for 223Ac results from decreasing quadrupole deformation. Other spectroscopic properties also confirm octupole deformation in these three isotopes. In 229Ac and 231Ac the only detailed but limited spectroscopic information comes from the (t, α) reaction on 230Th and 232Th. While it is consistent with the presence of parity doublets, much more detailed spectroscopic studies could give information about the possible coexistence of reflection asymmetry and reflection symmetry in these nuclei.
TL;DR: In this article, a detailed review of several Green's function methods for treating nuclear and other many-body systems is presented, including particle-particle hole-hole (pphh) Green's functions.
Abstract: We present an elementary and fairly detailed review of several Green’s function methods for treating nuclear and other many-body systems. We first treat the single-particle Green’s function, by way of which some details concerning linked diagram expansion, rules for evaluating Green’s function diagrams and solution of the Dyson’s integral equation for Green’s function are exhibited. The particle-particle hole-hole (pphh) Green’s function is then considered, and a specific time-blocking technique is discussed. This technique enables us to have a one-frequency Dyson’s equation for the pphh and similarly for other Green’s functions, thus considerably facilitating their calculation. A third type of Green’s function considered is the particle-hole Green’s function. RPA and high order RPA are treated, along with examples for setting up particle-hole RPA equations. A general method for deriving a model-space Dyson’s equation for Green’s functions is discussed. We also discuss a method for determining the normalization of Green’s function transition amplitudes based on its vertex function. Some applications of Green’s function methods to nuclear structure and recent deep inelastic lepton-nucleus scattering are addressed.
TL;DR: The rapidly growing research area of radioactive nuclear beam physics is described in this article, where various types of facilities used at present, and planned for the future, are discussed briefly, and their uses in research in nuclear physics, astrophysics, and in nuclear-solid state applications are discussed.
Abstract: The rapidly growing research area of radioactive nuclear beam physics is described. The various types of facilities used at present, and planned for the future, are discussed briefly. Then their uses in research in nuclear physics, astrophysics, and in nuclear-solid state applications are discussed. An intense effort in nuclear reaction physics has been directed toward understanding the neutron halo, a completely new result discovered for very neutron rich nuclei via the use of radioactive nuclear beams. Their use has also produced an immense amount of data on nuclear masses, lifetimes, decay modes, multipole moments, and energy levels. Other areas of research in nuclear physics with radioactive nuclear beams are less well developed, but appear to be promising. In nuclear astro-physics, several of the critical reactions of primordial and stellar nucleosynthesis have been studied. In addition, the use of radioactive nuclear beams has already provided dramatically improved definition of some of the processes of nucleosynthesis which operate near the proton and neutron drip lines, with the promise of much more detailed information to come. In more applied reasearch, the interaction between implanted nuclei and solids has often been used as a tool for nuclear physics, but the same studies can also be used to study properties of solids with previously unachievable sensitivity. The results in the past decade from radioactive nuclear beam research have been both vast and varied, but new facilities and intense interest in the research community should provide new information in the future well beyond that which presently exists.
TL;DR: In this paper, the energy of interaction between two nucleons by considering configurations which correspond to two B=1 solitons separated by a fixed distance is computed. But the results closely parallel the Skyrme-model calculations.
Abstract: We consider multibaryon configurations in a SU(2) quark soliton model based on chiral invariant quark-meson couplings. We compute the energy of interaction between two nucleons by considering configurations which correspond to two B=1 solitons separated by a fixed distance. The gross features of the inter-nucleon potential are reproduced. We also find cylindrically symmetric, classically stable soliton solutions with B=2, 3 and 4. The energy distributions corresponding to these solutions are toroidal in nature. The results closely parallel the Skyrme-model calculations.
TL;DR: In this article, the total cross-sections for, for incident neutrino energies from 16 MeV to 54 MeV, were reported, and theoretical values for comparison with the recent Karlsruhe-Rutherford Medium Energy Neutrino Experiment (KARMEN).
Abstract: We report here the total cross-sections for , for incident neutrino energies from 16 MeV to 54 MeV, so as to provide theoretical values for comparison with the recent Karlsruhe-Rutherford Medium Energy Neutrino Experiment (KARMEN). The effects of the isospin mixing from the 1+; T=0; 12.7 MeV level of 12C are taken into account. The effect of the only strong interaction induced weak magnetism form factor is studied, as well as that of the isovector axial coupling. The nuclear models used are the combination of general 1p-shell wave functions of Cohen-Kurath for the 15.1 MeV level, and Gillet-VinhMau particle-hole wave functions with 2ħω excitations for 12.7 MeV level. The neutrino (antineutrino) flux averaged sum is found to be 9.86×10−42 cm2without isospin mixing and 9.83×10−42 cm2with isospin mixing (δ=0.05) to be compared with the KARMEN result for the sum as [10.8±1.1(stat)±1.2(syst)]×10−42 cm2.
TL;DR: The spin-dependent generalized collective model was extended to arbitrary half-integer spins in this paper and applied to even-odd nuclei with spins 1/2 and 5/2.
Abstract: The Spin-dependent Generalized Collective Model, derived from a linearized collective Schrodinger equation in quadrupole coordinates, describes nuclei with spin 3/2 in the ground state. In this paper, we extend this model to arbitrary half-integer spins and apply it to even-odd nuclei with spins 1/2 and 5/2.
TL;DR: In this paper, the theory of heavy ion reactions with particle transfer is considered in the framework of the exact finite-range distorted wave Born approximation (EFR-DWBA) and modified Woods-Saxon potentials which include a parity dependent interaction and an angular momentum absorptive term have been used as the ion-ion interactions in the initial and final channels.
Abstract: The theory of heavy ion reactions with particle transfer is considered in the framework of the exact finite-range distorted wave Born approximation (EFR-DWBA). Modified Woods-Saxon potentials which include a parity dependent interaction and an angular momentum absorptive term have been used as the ion-ion interactions in the initial and final channels. The bound state interactions are represented by nucleus-nucleus inter-actions which include repulsive and attractive Yukawa type components. The present numerical calculations of the differential cross-sections are in good agreement with the experimental measurements. The distorting parity dependent potentials are found very important in reproducing the cross-sections at backward as well as at intermediate angles. The obtained extracted values of the spectroscopic factors are reasonable.
TL;DR: The microscopic origin of deformation for heavy nuclei is discussed in this paper, where it is shown that the systematic features of nuclear deformation are determined primarily by filling of the normal-parity shell model orbitals of the valence shells, and that the abnormal parity orbitals play crucial but subsidiary roles.
Abstract: The microscopic origin of deformation for heavy nuclei is discussed. Evidence is presented that the systematic features of nuclear deformation are determined primarily by filling of the normal-parity shell model orbitals of the valence shells, and that the abnormal-parity orbitals play crucial but subsidiary roles. This is in accord with the point of view underlying the Fermion Dynamical Symmetry Model. In addition, we demonstrate that the deformation systematics of the FDSM are consistent with those of the Nilsson model, despite their very different starting points, and that the assumptions of the FDSM are consistent with the assertion that the n-p quadrupole-quadrupole residual interaction is the essential reason for deformation. Finally, application of the same principles to superdeformation suggests that abnormal parity orbitals have a much more direct influence on superdeformation than on normal deformation.
TL;DR: In this paper, the double neutron capture reaction 169Tm(n,γ)170Tm (n, ε)171Tm and the proton transfer reaction 170Er(3He,d)171tm were used to study nuclear levels in 171Tm.
Abstract: The double neutron capture reaction 169Tm(n,γ)170Tm(n,γ)171Tm and the proton transfer reaction 170Er(3He,d)171Tm were used to study nuclear levels in 171Tm. The level scheme up to 1 MeV was confirmed and very precise level energies were determined. The results are compared with the quasiparticle-phonon model. Evidence was found, that the 1/2−[541] orbit has larger deformation than the other states.
TL;DR: In this paper, a rotating deformed nucleus modeled by a selfconsistent cranked anisotropic oscillator mean field with BCS pairing is considered, and the expectation value of the Kelvin circulation operator depends upon the deformation and upon the strength of the pairing field.
Abstract: The Kelvin circulation vector is the hermitian kinematical observable that measures the true character of nuclear rotation. For a rotating deformed nucleus modeled by a selfconsistent cranked anisotropic oscillator mean field with BCS pairing, the expectation value of the Kelvin circulation operator depends upon the deformation and upon the strength of the pairing field. For zero pairing, the circulation acquires its rigid rotor value. As the pairing field increases, the circulation tends to zero, the irrotational flow limit. At critical values of the pairing field, the deformation and circulation make abrupt phase transitions.
TL;DR: In this article, a kinematic coincidence technique employing position sensitive silicon detectors was used to obtain the mass identification of binary events in the elastic excitation function of the 46Ti(58Ni, 58Ni)46Ti elastic scattering in the 58Ni incident energy range from 216.2 to 240 MeV.
Abstract: In a search for possible resonant behavior in medium and heavy composite systems, the 46Ti(58Ni, 58Ni)46Ti elastic scattering was studied in the 58Ni incident energy range from 216.2 to 240 MeV. A kinematic coincidence technique employing position sensitive silicon detectors was used to obtain the mass identification of the binary events. Evidence was found for two structures of non-statistical nature in the elastic excitation function at, respectively, incident 58Ni energies of 223.9 and 227.4 MeV (Ecm=99.0 and 100.6 MeV). A statistical analysis of the corresponding angular distributions disclosed periodical behavior analogous to that caused by single partial waves of J=(36 ± 1) and (47 ± 1), respectively.
TL;DR: In this paper, the prediction of supersymmetric quantum mechanics that bands with identical gamma-ray energies occur in quartets was examined, and the experimental data suggest that this scenario is actually realized in nature.
Abstract: We examine the prediction of supersymmetric quantum mechanics that bands with identical gamma-ray energies occur in quartets. The experimental data suggest that this scenario is actually realized in nature. In the A=150 mass region, four known pairs of isospectral bands can be grouped in two quartets, while there are indications of such patterns around A=190. We introduce a small supersymmetry breaking, necessary to describe the details of the data. We derive relations among the transition rates that can be used to test our predictions.
Abstract: This review summarizes both the experimental and theoretical status of cluster radioactivity. The contents are: a brief introduction, the experimental methods used and the results obtained, the theories of cluster radioactivity, cluster-decay as (cold) super-asymmetric spontaneous fission, and its fine structure. The theories studied are the unified fission models (UFM), the preformed cluster models (PCM), and the comparison between empirical and theoretical preformation probabilities. A brief discussion of other theories, not studied so much in detail, is also given. An overview of this research is added at the end, pointing out, in particular, its relation to other phenomena.
TL;DR: In this article, a general agreement was found for all the reactions of (α, xn) type of reactions, however, the model failed badly in all cases of zα, zαxn)type of reactions.
Abstract: Alpha particle-induced reactions on the target element vanadium were investigated from threshold up to 55 MeV using the foil-stack activation technique and the Ge(Li) gamma ray spectroscopy method. Excitation functions for the formation of reaction residues 54Mn, 52Mn, 51Cr, 48V, 47Sc, 46Sc were investigated. The experimental cross-sections were compared with the predictions based on updated hybrid model (ALICE/90) using n0=4 (4p0h) and level density parameter a=A/9. A general agreement was found for all the reactions of (α, xn) type. However, the model failed badly in all cases of (α, zαxn) type of reactions.
TL;DR: In this paper, the energy difference between members of the Pairing Triplet could be understood in the framework of charge independence, defined as the difference between the residual energies of 2n and 2p states, could be interpreted as the Coulomb interaction between the two protons of the pair.
Abstract: The energy difference between members of the Pairing Triplet could be understood in the framework of charge independence. In the case of two-nucleon analogue stretched states, an estimation more refined than the addition rule is suggested to calculate the energy of pn or 2p states when the energy of 2n states is known. ec, defined as the difference between the residual energies of 2n and 2p states, could be interpreted as the Coulomb interaction between the two protons of the pair. The mean distances between the two nucleons, coupled to their minimum spin value and to their maximum spin value, could then be deduced illustrating the Pauli principle. Mirror members of an isospin triplet have similar lifetime and branching ratios, while the Tz=0 member has quite different properties due to the nonconservation of isospin in electromagnetic interaction. The state of the Tz=0 nuclei should decay through M1 transition of about 3 MeV to the state, and should have a short lifetime of about 1 fs. Charge independence could be tested by populating high-spin two-nucleon stretched states with 36Ar as the projectile. Proton-rich beam would be of interest to form mirror compound nucleus. Both compound nucleus and mirror compound nucleus would preferentially evaporate protons.
TL;DR: In this article, the Bohm-Pines method was used to calculate the binding energy per nucleon in the ground state of a nuclear matter, which gave rise to a saturation Fermi wave vector kFO=1.74 fm−1, which is larger than the mostly accepted value of 1.43 fm −1.
Abstract: By invoking the existence of the zero-sound mode we have succeeded in generalizing the Bohm-Pines method, for the collective description of the interparticle interactions in a dense electron gas, to calculate the binding energy per nucleon in the ground state of a nuclear matter. The present calculation gives rise to a saturation Fermi wave vector kFO=1.74 fm−1, which is larger than the mostly accepted value of 1.43 fm−1. Our calculated result for the velocity of the zero-sound mode is found to be well-agreeable with those of other theories. It is further seen that there is an instability in the nuclear matter, with respect to long wavelength density fluctuations, in the low density region n≤0.78n0, n0 being the saturation nuclear density. From the present theory, we obtain a compression modulus K=116.7 MeV at the saturation density, which is smaller than the well-known result (210±30) MeV. However, by adjusting the value of the effective mass, M*, of the nucleon, we are able to reproduce the correct result for the compression modulus. Such a value of M* is found to be greater than the bare nucleon mass M. From the present theory, we obtain the energy of the monopole resonance Eph=32.38 MeV, which agrees reasonably well with the experimental data for heavy nuclei. By lowering the value of the saturation Fermi wave vector, we observe a decrease in the value of the compression modulus, which is just the opposite to the results of other theoretical calculations.
TL;DR: In this article, the authors discuss the origin of scale-invariant, intermittent fluctuations in the cluster fragmentation models such as the percolation model and the binary cascading models.
Abstract: Recent theoretical developments in the kinetic fragmentation theory are presented with a particular emphasis on the newly proposed Fragmentation-Inactivation Binary (FIB) cascading model. We also discuss the origin of scale-invariant, intermittent fluctuations in the cluster fragmentation models such as the percolation model and the binary cascading models.
TL;DR: In this article, the effects of the finite size of the nucleus in the electromagnetic excitation of the quasi-elastic peak have been studied by comparing the responses calculated for 12C and 40Ca with the Fermi gas and the shell model.
Abstract: The effects of the finite size of the nucleus in the electromagnetic excitation of the quasi-elastic peak have been studied by comparing the responses calculated for 12C and 40Ca with the Fermi gas and the shell model. The contribution of the Meson Exchange Currents has also been considered. We have investigated the possibility of improving the Fermi gas model with approximate estimations of the finite size effects. We found that the use of an effective Fermi momentum provides a better description of the shell model results than the Local Density Approximation.
TL;DR: In this paper, the experimental knowledge and theoretical understanding of the deuteron matter radius are reviewed, and an experimental value of rm(exp)=1.9502 (20) fm is found by using the 1962 Stanford data, the 1973 Monterey data, and the 1981 Mainz data for the ratio of electron-deuteron to electron-proton elastic scattering cross-sections, plus the 1979 Erevan data and the 1990 Saclay data on electron-Deuteron elastic cross-section.
Abstract: Experimental knowledge and theoretical understanding of the deuteron matter radius are reviewed. An experimental value of rm(exp)=1.9502 (20) fm is found by using the 1962 Stanford data, the 1973 Monterey data and the 1981 Mainz data for the ratio of electron-deuteron to electron-proton elastic scattering cross-sections, plus the 1979 Erevan data and the 1990 Saclay data on electron-deuteron elastic cross-sections. The theoretical radius is dominated by a model-independent part, 1.9557 (7) fm or 1.0028 rm (exp) in magnitude, determined by the triplet scattering length, the deuteron binding energy, and the triplet effective range. The remaining contribution to the theoretical radius is model-dependent. It gives about 0.0110 fm, or 0.0056 rm(exp), for the Bonn potentials which have relatively weak short-range tensor forces. Experiment and theory thus differ by 0.8%. This discrepancy cannot be understood in terms of known physical processes involving relativity, meson exchanges, and abnormal higher-mass components of the wave function. Interestingly, the five experimental results can be separated into two inconsistent groups: (a) The Stanford and Saclay results agree, giving a weighted average of 1.967 (5) fm in agreement with theory. (b) The Monterey, Mainz and Erevan results also agree, giving a weighted average of 1.9488 (21) fm in disagreement with theory. The possibility of obtaining nuclear-size information from atomic Lamb shift measurements is also reviewed. In particular, the latest deuterium-hydrogen isotope shift of the 1S-2S Lamb shift yields a deuteron matter radius of 1.963 (5) fm. New measurements of both deuteron and proton charge radii would be of great interest in both nuclear and atomic physics.