Nucleus Interactions Research Articles

Influence of polarization of hot nuclear matter on the anomaly of surface diffuseness of inter-nuclear potential

The fusion excitation functions for 12 colliding systems with 96 ≤ Z 1 Z 2 ≤ 608 are analyzed using coupled-channel (CC) calculations based on the M3Y double-folding (DF) potential supplemented with a repulsive potential that takes into account the incompressibility of the nuclear matter. We also applied the polarization effects of hot nuclear matter (PEHNM) on the calculations of the bare nucleus–-nucleus interaction potential within the framework of the modified density-dependent Seyler–Blanchard (SB) approach in the T 2 approximation. Our results reveal that we obtain a nice description of the experimental data of different fusion systems when we use the present theoretical approach to calculate the energy-dependent values of the fusion cross sections. In this paper, the influence of the PEHNM on the surface diffuseness parameter of the Woods–Saxon (WS) potential is also studied. In order to reach this goal, we extract the corresponding values of this parameter based on the modified form of the DF potential (M3Y+Repulsion+polarization). We find that the extracted values are located in a range between a = 0.61 and 0.80 fm at different incident energies. It seems that the polarization effects of hot nuclear matter play a key role in describing the abnormally large values of the nuclear potential diffusenesses in the heavy-ion fusion reactions. Additionally, the regular decreasing trend for the diffuseness parameter of the nucleus–nucleus potential with the increase in the bombarding energies is also observed.

A Review on Study Short-Range Correlations and the Isospin Dependence

High-energy electron scattering can be considered a crucial tool for interpreting the function of high-momentum nucleons (and quarks) in nuclei and offers a clean, accurate probing for investigations of hadronic and nuclear organization. The intense repulsion of nuclear contact at small distances is the source of short-range interactions in nuclei and nuclear matter. These connections have been verified in several nuclear tests using hadronic and electroweak probes. Improved knowledge of the underlying structure of these high-momentum and short-range arrangements in nuclei will be crucial for a variety of high-energy observables. The short-range correlations also appear to be associated with changes in the quark distributions in nuclei. Over the past ten years, there has been a significant concentration on both theoretical and experimental efforts aimed at characterizing short-range correlations, namely their isospin dependence. In this review, it will employ a theoretical framework rooted in many-body Green's functions theory. Specifically, review focus on the one-body momentum distributions as a fundamental variable. The objective is to provide a concise overview of the latest research findings in the field.

Study of spectroscopic properties of some nuclei participating in (μ-, e-) lepton flavor violation process

Lepton flavor violation (LFV) is a clear sign of new physics beyond the standard model. A prominent process concerning LFV is μ- ⟶ e- conversion in a muonic atom. In the present work, we have investigated the spectroscopic properties of three nuclei namely 24Mg, 32S, and 44Ca which participate in this μ- ⟶ e- lepton flavor violating process. We have used USD interaction for sd shell nuclei namely 24Mg and 32S and Z20 Bonn interaction for pf shell nucleus 44Ca, to calculate these properties.

Bonner sphere measurements of high-energy neutron spectra from a 1 GeV/u 56Fe ion beam on an aluminum target and comparison to spectra obtained by Monte Carlo simulations

The goal of this work is to characterize the secondary neutron spectra produced by 1 GeV/u56Fe beam colliding with a thick cylindric aluminum target and to perform a quantitative comparison with simulated results obtained with Monte Carlo codes. The measurements were performed using extended-range Bonner sphere spectrometers at two positions (15° and 40°) with respect to the beam direction. The secondary radiation field was simulated using four Monte Carlo codes (FLUKA, MCNP6, Geant4 and PHITS) and several physical models of nuclei transport and interaction. Neutron and proton energy distributions were simulated for the experimental measurement positions. The simulated neutron spectra, together with data measured with Bonner sphere spectrometers, after carrying out the correction of the contributions induced by the secondary protons, were used as input for the MAXED spectrum unfolding code to obtain the measured neutron spectra. Unfolded neutron spectra were compared with simulated ones to carry out a quantitative analysis of the performance of the chosen Monte Carlo codes and their corresponding physical models. This comparison showed that, because of experimental uncertainties and physical models, there are no unique solutions for each measurement location, but a range of solutions where the true experimental neutron spectra probably lie. The results showed deviations between 4.23% and 8.42% for some simulated spectra. Regarding the total integral values of neutron fluence and ambient equivalent dose, the unfolded neutron spectra showed deviations lower than 2%.

Approximate Effective Interaction for Nuclear Matter and Finite Nuclei

In this paper, an approximate effective nucleon-nucleon interaction for nuclear matter and finite studies has been derived using the lowest order constrained variational (LOCV) approach. The LOCV method, a functional minimization procedure, uses a normalization constraint to keep higher-order terms as small as possible. As a first step, two-body matrix elements based on the Reid93 nucleon-nucleon potential were calculated for the nuclear system A = 16 in a harmonic oscillator basis, with the oscillator size parameter <i>ћω </i>= 14.0 MeV, and separated into the central, spin-orbit and tensor channels in conformity with the potentials for Inelastic scattering. Following this, a least squares fitting of the matrix elements to a sum of Yukawa functions was performed to determine the strengths of the effective interaction in the singlet-even, singlet-odd, triplet-even and triplet-odd (Central); tensor-even and tensor-odd (Tensor); spin-orbit-even and spin-orbit-odd (Spin-orbit) channels. Of all the matrix elements, only the triplet-even and tensor-even components, being attractive, are affected by the tensor correlations (<i>a </i>= 0.05); and are shown to exhibit the same trend of variation in conformity with past work, in terms of magnitude, as one goes from the lower-node quantum numbers (n’, n) = (0, 0) to higher ones (n’, n) = (2, 2). When compared with the G-matrix results of previous researchers, the results obtained herein have been found to be in good agreement. This, therefore, gives hope that the new effective interaction promises to be a reliable tool for nuclear matter and nuclear structure studies.

Analytical description of the time-over-threshold method based on time properties of plastic scintillators equipped with silicon photomultipliers

A new highly granular neutron detector (HGND) for the identification and energy measurement of neutrons produced in nucleus–nucleus interactions at the BM@N experiment, Dubna, Russia, at energies up to 4 AGeV is under development. The detector consists of approximately 2000 fast plastic scintillators, each with dimensions of 40 × 40 × 25 mm3, equipped with SiPM (Silicon Photomultiplier) with an active area of 6 × 6 mm2. The signal readout from these scintillators will employ a single-threshold multichannel Time-to-Digital Converter (TDC) to measure their response time and charge using the time-over-threshold (ToT) method. This article focuses on the analytical description of the signals from the plastic scintillator detectors equipped with silicon photomultipliers. This description is crucial for establishing the ToT to charge relationship and implementing slewing correction techniques to improve the time resolution of the detector.

Hadronuclear Interactions in Active Galactic Nuclei Jets as the Origin of the Diffuse High-energy Neutrino Background

The origin of diffuse high-energy neutrinos from TeV to PeV energies detected by the IceCube Observatory remains a mystery. In our previous work, we have shown that hadronuclear (p − p) interactions in active galactic nuclei (AGNs) jets could be important and generate detectable very-high-energy emissions. Here, we further explore these interactions in the AGN jets based on their luminosity function. The diffuse neutrino flux and corresponding γ-ray flux have been calculated and compared with observational data. In our modeling, two beaming patterns are considered separately. To make sure that the corresponding γ-ray flux does not overshoot the diffuse γ-ray background, we find that if the neutrino production region in a jet is opaque to γ-rays, p − p interactions in AGN jets with a small viewing angle (the blazar case) are able to interpret the PeV neutrino background. Similarly, AGN jets with a large viewing angle (the radio galaxy case) may interpret the TeV neutrino background. While, if the neutrino production region is transparent to γ-rays, only blazars have the potential to interpret the diffuse neutrino background around the PeV band. Some caveats are also discussed.

Modeling of Cluster Decay of Light Nuclei by the Interaction of the 9Be Nucleus with Fast Neutrons in an Ionization Chamber

Modeling of Cluster Decay of Light Nuclei by the Interaction of the 9Be Nucleus with Fast Neutrons in an Ionization Chamber

Impact of Zeeman and hyperfine interactions on the magnetic properties of paramagnetic metal Ions: III. Analysis of the local interactions in a single crystal of 173Yb3+ doped Y5SiO5

The electron spin echo envelope modulation (ESEEM) technique is a direct method to probe the nuclear spin coherences induced by electron spin transitions. Recently, this approach was used to study an isotopically pure Y2SiO5 crystal doped with 173Yb3+ ions, and the presence of the Fermi contact interaction was proposed to explain the frequency comb detected in the two-pulse ESEEM experiment [Solovarov N. K. et al. JETP Letters 115 (6): 362–67]. Here we simulate the Fourier images of the ESEEM data. The numerical analysis shows that the modulation is mainly due to the nuclear spin coherences induced by the dipole–dipole interactions. However, the correlation between the experimental and simulated data is better when the super-hyperfine interactions of the nearby yttrium nuclei have an additional isotropic contribution. The analysis of the rescaled X-band ESEEM spectra shows that for the EPR transitions at magnetic fields > 100 mT, the main contribution to the modulation comes from the oscillations of the individual nuclei and the effect of interference between coherences originating from several nuclei is not strong. Further experiments to distinguish the sources of the echo modulation are discussed.

Determining patterns of leaching titanium(IV) from the Irshansky deposit ilmenite

The research object is the ilmenite concentrate from the Irshansky deposit. This study describes an elemental composition of the mineral raw material and confirms its structure using the X-ray diffraction and scanning electron microscopy. Experimental studies have shown that the ilmenite concentrate from the Irshansky deposit has a significant titanium content in terms of titanium dioxide (79 %). Mineral raw materials with such a chemical composition are unique, so there is a need to find alternative methods for its processing. The research demonstrates that the maximum degree of extraction in the process of alkaline leaching of the ilmenite concentrate is achieved under the condition that the average diameter of particles of the mineral raw material should be ≤71 μm. As a result of temperature studies, it has been found that a temperature of 453 K would suffice to obtain potassium titanate at atmospheric pressure. Further temperature increase does not provide for a significant increase in the degree of titanium extraction, and also contributes to the formation of polytitanates of various compositions. The study of the influence of the molar ratio of the starting reagents on the degree of extraction of titanium(IV) from the ilmenite concentrate has showed that the optimal molar ratio between the components corresponds to the stoichiometric one and is 1:2. Increasing the amount of potassium hydroxide in the reaction mixture is impractical as it reduces the yield of potassium titanate, and the final product will have high alkalinity due to excess alkali. The optimal time for alkaline leaching is three hours of continuous heating in a glycerin bath. A further increase in the duration of heating does not lead to an increase in the degree of extraction, which is associated with the diffusion of alkali from the surface of the nucleus into the volume of ilmenite particles due to the formed products of interaction and annihilation of the initial nuclei

Effect of Cobalt on the Microstructure of Fe-B-Sn Amorphous Metallic Alloys

Fe78B15Sn7 and (Fe3Co1)78B15Sn7 amorphous metallic alloys were prepared using the method of planar flow casting. The amorphous nature of ribbons containing 7 at. % Sn was verified by X-ray diffraction. The resulting chemical composition was checked by flame atomic absorption spectroscopy and by mass spectrometry with inductively coupled plasma. The microstructure of the as-quenched metallic glasses was investigated by 57-Fe and 119-Sn Mössbauer spectrometry. The experiments were performed with transmission geometry at 300 K, 100 K, and 4.2 K, and in an external magnetic field of 6 T. The replacement of a quarter of the Fe by Co did not cause significant modifications of the hyperfine interactions in the 57-Fe nuclei. The observed minor variations in the local magnetic microstructure were attributed to alterations in the topological short-range order. However, the in-field 57-Fe Mössbauer spectra indicated a misalignment of the partial magnetic moments. On the other hand, the presence of Co considerably affected the local magnetic microstructure of the 119-Sn nuclei. This was probably due to the higher magnetic moment of Co, which induces transfer fields and polarization effects on the diamagnetic Sn atoms.

Magnetic hyperfine interactions of probe 57Fe atoms within the hexagonal manganite ScMnO3

Here we present the Mössbauer study of the combined magnetic and electrical hyperfine interactions of the probe 57Fe nuclei localized in the hexagonal manganite ScMnO3. The hyperfine interactions were measured in the temperature range where ScMnO3 demonstrates spin ordering: 15 K <T <TN (∼ 130 K). By analyzing the hyperfine parameters of 57Fe nuclei, we evaluated the oxidation state of the iron ions, their local crystal environment, and the orientation of the magnetic moments μFe in the structure of ScMn0.99657Fe0.004O3 at T <<TN. The temperature-dependent evolution of Zeeman structures in Mössbauer spectra was analyzed using the stochastic relaxation model, and indicates the presence of frustration of the superexchange interactions Fe3+−O−Mn3+. The temperature dependence of the hyperfine magnetic field Bhf(T) was described using critical indices, whose values reflect the reduced dimensionality of the magnetic system under study. It was shown that the observed sharp temperature-dependent change of the quadrupole shift of the Zeeman structure components may be attributed to the spin reorientation process, resulting in antiferromagnetism with a weak ferromagnetic component.

Cross sections of neutral-current neutrino scattering on 98,100Mo isotopes

Coherent elastic neutrino–nucleus scattering (CEνNS) is a neutral-current low-energy electro-weak reaction-channel detected recently by the COHERENT experiment at the Oak Ridge National Laboratory (ORNL), USA, in the Spallation Neutron Source facility. The extremely weak signal on the CsI detector of the first experiment and on the liquid Ar of the repeated COHERENT experiment is the energy-recoil due to the neutrino–nucleus interaction, where the nucleus is elastically scattered as a whole while simultaneously the neutrino goes out. Today, several promising nuclear detectors are on the way to be employed in designed and ongoing experiments. In our present work, we provide predictions for incoherent scattering cross sections of low-energy neutrinos on 98,100Mo isotopes obtained with the deformed shell model employed previously for similar predictions in other electroweak processes. We mention that, Mo detector medium has been used previously in the MOON and NEMO double beta decay experiments.

Multiplicity correlation of fast target protons and projectile fragments for the events produced in the interaction of 84Kr nuclei with emulsion nuclei at 1 A GeV

It has become obvious that one crucial aspect in understanding high energy nuclear reactions is the fragmentation of colliding nuclei. The nuclear emulsion is a 4[Formula: see text] detector that makes it simple to identify and quantify the charges of projectile fragments. In this work, we study the multiplicity distribution and angle distributions of single, double charge projectile fragments, fast target protons (gray particle) as well as their correlation for the events produced in the interactions of [Formula: see text] with emulsion nuclei at 1[Formula: see text]A[Formula: see text]GeV. We also study the target-dependent angle distribution of gray particles. The results are compared with other experimental data as per availability. This analysis shows that multiplicity distributions have a remarkable link between the projectile and target fragmentation processes.

Hyperfine excitation of NH and ND by molecular hydrogen

The NH and ND radicals are of key importance in the comprehension of nitrogen chemistry and the enhancement of deuterated molecules in the interstellar medium. Observations by space telescopes yield spectra that can resolve the fine and hyperfine structure of these radicals, a consequence of the electronic and magnetic interactions of nitrogen, hydrogen, and deuterium nuclei. Accurate rate coefficients, induced by collisions with H2, are required to interpret spectra of these radicals. We report the first rate coefficients for fine and hyperfine transitions of NH and ND in collision with both ortho- and para-H2. Based on a recent four-dimensional potential energy surface, fine-structure resolved cross sections and rate coefficients are computed with the time-independent close-coupling method over a temperature range of 5–300 K. Our calculations include the first 25 energy levels of NH and ND. Hyperfine resolved cross sections and rate coefficients are determined using the infinite-order sudden (IOS) approximation between 5 and 200 K for NH and 100 K for ND. We consider the first 71 and 105 energy levels of NH and ND, respectively. General propensity rules are discussed. We found a significant isotopic substitution effect in the rate coefficients. In addition, the rate coefficients for collisions with H2 are larger than those with He by a factor of up to 5, leading to lower critical densities for collisional excitation with H2 than He. The impact of the new set of collisional data has been investigated in simple radiative transfer models of the NH emission seen toward the Orion Bar and the ejecta of the η Carinae binary star. We observed significant differences by a factor of 5 between the presently determined column densities for NH compared to those from the literature using He as a collider.

Role of induced elastic deformations at the Mg/MgH2 transformation

The kinetics of magnesium hydride formation depends on many factors such as thermodynamic conditions, the presence/absence of additives and the mechanical treatments applied to the starting material. As a result, the impact on the reaction of the material is complex. Additionally, during repeated hydrogenation/dehydrogenation cycles, the microstructure of the material becomes significantly different from the original one. In such case, it is not so simple to order the relative importance of the different experimental contributions. In fact limited research efforts have been devoted to the impact of elastic deformation and its direct consequences on the hydride nucleation process. This motivates the present theoretical analysis of the mechanical energy balance between the Mg and MgH2 entities. Here the formation and interaction of a hydride nucleus with structural defects as a pore or a free surface is carried out in the Mg-MgH2 system.The present work evidences that calculation makes it possible to underline and unequivocally analyze the importance of a single parameter among a set of multiple factors that potentially have an impact on the kinetic processes. It is demonstrated here that due solely to the change in volume during hydride nucleation, conditions develops in the magnesium matrix for predominant release of hydride onto free surfaces, including pores.The calculation of the energy balance made it possible to classify the local impact on the nuclei for different typical configurations such as the vicinity of a free surface, a boundary and the vicinity of low rigidity defects (e.g. pores, vacancies, etc.). Hydride formation near a surface (external or internal, a twin plane or a grain boundary, etc.) results in a reduction in mechanical energy terms, which favors the easy nucleation step in magnesium. Nucleation occurs primarily on free surfaces rather than in bulk.

Exploring anisotropic flow via the Boltzmann transport equation employing the Tsallis blast wave description at LHC energies

Anisotropic flows i.e. azimuthal anisotropies in the particle production are one of the important probes in characterizing the properties of the strongly interacting matter created in the relativistic heavy-ion collisions. These observables are sensitive to both the transport properties as well as the equation of state of the quantum chromodynamics matter. We have adopted the Boltzmann transport equation (BTE) in the relaxation time approximation to describe the experimental data for harmonic flows such as elliptic flow (v 2), triangular flow (v 3), quadrangular flow (v 4) obtained in heavy-ion collisions at large hadron collider (LHC) energies. In this analysis, we have used Tsallis statistics as an initial distribution and the Tsallis blast wave description is used as the equilibrium distribution function while describing the evolution of the particle production in BTE. We have fitted the transverse momentum spectra, v 2, v 3, and v 4 of identified hadrons such as pion, kaon, and proton for Pb–Pb and Xe–Xe collisions at the LHC energies of sNN = 5.02 TeV and sNN = 5.44 TeV, respectively for various centralities. Our study offers the comparative analysis between the two distinct collision systems operating at comparable collision energies. The present formulation successfully fits the experimental data for p T - spectra upto p T = 8 GeV and effectively explains the anisotropic flows data upto p T = 10 GeV with a very favourable χ 2/ndf. We observe that the average transverse flow velocity (〈β〉) and the kinetic freeze-out temperature (T) extracted in our analysis decrease as we go towards the peripheral collisions. Non-extensive parameters (q AA and q pp ) exhibit an ascending trend from central to peripheral collisions, signifying an almost thermalized system in the most central collisions and a non-equilibrium state in peripheral ones. The azimuthal modulation amplitudes (ρ a ) for v 2, v 3, and v 4 exhibit an increasing pattern as one moves from the most central to peripheral collisions in both the Pb–Pb and Xe–Xe nuclei interactions.

Microglia-neuron interactions in the caudate nucleus in different course of schizophrenia

To study the ultrastructure of microglia and neurons in contact with each other in the head of the caudate nucleus in continuous schizophrenia (CS) and paroxysmal-progressive schizophrenia (PPS) as compared to controls and to analyze correlations between the parameters of microglia and neurons in the control and schizophrenia groups. Post-mortem electron microscopic morphometric study of microglia and neurons in contact with each other was performed in the head of the caudate nucleus in 9 cases of CS, 10 cases of PPS and 20 controls without mental pathology. Group comparisons were made using analysis of covariance and Pearson correlation analysis. The PPS group showed increased numerical density of microglia in young (≤50 years old) patients compared to elderly (>50 years old) controls and increased area of endoplasmic reticulum vacuoles in microglia in young patients compared to young controls. Decreased numerical density of microglia was found in the CS group compared to the PPS group (p<0.05), and increased volume fraction (Vv) and the number of lipofuscin granules in microglia were found in the CS group in elderly patients compared with young and elderly controls. In this group, negative correlations were revealed between the numerical density of microglia, microglia nuclear area and the duration of disease (r= -0.72, p=0.03; r= -0.8; p=0.01). Decreased Vv and the number of mitochondria in microglia and increased area and perimeter of neurons were revealed in both groups compared to the control group. In neurons, increased vacuole area was found in the PPS group and mitochondrial area in the NTS group compared to the control group. Correlation violations were found between the parameters of mitochondria in microglia and neurons in both PPS and CS groups and between the area of mitochondria in neurons and the area of vacuoles in microglia in the CS group compared to the control group. Disturbed interactions between microglia and neurons in the caudate nucleus are associated with the types of course of schizophrenia and with microglial reactivity. They might be caused by the damage of energy metabolism in microglia in both types of schizophrenia course and by stress of endoplasmic reticulum in microglia in CS.

Very large neutron-nucleus scattering lengths

The interaction of neutrons and nuclei at low energies may potentially lead to strongly resonant states, characterized by scattering lengths several orders of magnitude larger than the effective range of the interaction. In order to explore the scattering of neutrons off unstable nuclei, we describe a simple analytical formalism to characterize the scattering parameters of a neutron-nucleus system created following the fast removal of a few nucleons from a slightly heavier beam. The case of the n-17B system is considered, and the implications of a potentially very large scattering length on the structure of 18,19B discussed.

ΔS = 0 hadronic parity violation in next-to-leading order QCD: Anomalous dimension matrices and their implications

We construct the effective Hamiltonian for hadronic parity violation in strangeness-nonchanging (ΔS=0) processes in next-to-leading order (NLO) in QCD, for all isosectors, and at a renormalization scale of 2GeV, thus extending our earlier leading-order (LO) analysis [1,2]. Hadronic parity violation, studied in the context of the low-energy interactions of nucleons and nuclei, exposes the complex interplay of weak and strong interactions in these systems, and thus supports our extension to NLO. Here we exploit the flavor-blind nature of QCD interactions to construct the needed anomalous dimension matrices from those computed in flavor physics, which we then use to refine our effective Hamiltonian and finally our predicted parity-violating meson-nucleon coupling constants, to find improved agreement with few-body experiments.