Nucleon Energy Research Articles

Soliton, breather and shockwave solutions of the Heisenberg and the Toverline{T} deformations of scalar field theories in 1+1 dimensions

In this note we study soliton, breather and shockwave solutions in certain two dimensional field theories. These include: (i) Heisenberg’s model suggested originally to describe the scattering of high energy nucleons (ii) Toverline{T} deformations of certain canonical scalar field theories with a potential. We find explicit soliton solutions of these models with sine-Gordon and Higgs-type potentials. We prove that the Toverline{T} deformation of a theory of a given potential does not correct the mass of the soliton of the undeformed one. We further conjecture the form of breather solutions of these models. We show that certain Toverline{T} deformed actions admit shockwave solutions that generalize those of Heisenberg’s Lagrangian.

Distillation at high momentum

Extraction of hadronic observables at finite-momenta from Lattice QCD (LQCD) is constrained by the well-known signal-to-noise problems afflicting all such LQCD calculations. Traditional quark smearing algorithms are commonly used tools to improve the statistical quality of hadronic $n$-point functions, provided operator momenta are small. The momentum smearing algorithm of Bali et al. extends the range of momenta that are cleanly accessible, and has facilitated countless novel lattice calculations. Momentum smearing has, however, not been explicitly demonstrated within the framework of distillation. In this work we extend the momentum-smearing idea, by exploring a few modifications to the distillation framework. Together with enhanced time slice sampling and expanded operator bases engendered by distillation, we find ground-state nucleon energies can be extracted reliably for $\left|\vec{p}\right|\lesssim3\text{ GeV}$ and matrix elements featuring a large momentum dependence can be resolved.

Cosmic Rays and Ultra High Energy Cosmic Rays (UHECR), GZK (Greisen-Zatsepin-Kuzmin) cutoff, Deflection angle of high energy cosmic rays in the propagation through the galactic and extragalactic magnetic fields, Auger Surface Detector and the Monitoring Data, Measurement of the Lifetime of Muons and Pions and The Variant Mass for a Particle in a Gravitational Field and the Binary Stars: The

The Surface Detector of the Pierre Auger Observatory consists of 1600 water Cherenkov tanks sampling ground particles of air showers produced by energetic cosmic rays. Every water tank is equipped with three photomultipliers (PMTs). Every 7 minutes monitoring data are recorded from each surface detector to ensure that they are performing as intended and also to understand the detector behavior. The monitoring data set is used to study the evolution of parameters of the PMTs as a function of both time and temperature. The main objective of the monitoring data is to monitor the stability of the PMTs. In case there is abnormal behavior detected, an alarm entry is created in the database. The classification of the alarms into different categories, corresponding to the observed patterns of the PMT variables and the decision of the alarm level are subject of this work. It is also researched the photomultipliers parameters and the alarm creation with examples of it: the Free Disk and High PMT gain change Alarms using c++, root and mysql. For other hand, it is researched about the measurement of the lifetime of muons and pions theoretically, experimentally and with the application of Statistics for the uncertainties of the results. The results have high accuracy and in accordance with the values of the literature. In addition, it is to analyze theoretically the deflection angle of the high energy cosmic rays in the propagation through the galactic and extragalactic magnetic fields. It is used the magnetic force formula and the Larmor radius, trigonometry, and the tables for the values of the galactic and extragalactic magnetic field and the distances to the galactic and extragalactic sources. It is possible to observe from this analysis that the deflection angles are very small for the considered cases. Thus, UHECR arrival directions should point back to their sources in the sky. Besides, it is researched about the GZK (Greisen-Zatsepin-Kuzmin) cutoff. A sharp cutoff at approximately several times 1019 eV in the energy spectrum of the cosmic rays is expected due to the energy degradation of the cosmic rays through their interaction with photons of the microwave background radiation. It is known as the GZK (Greisen-Zatsepin-Kuzmin) cutoff. A nucleon with an initial energy above Eo=1020 eV lose about 1/5 of Eo (initial energy) in each interaction. Thus, a nucleon of initial energy above 1020 eV will reduce its energy to 6*1019 eV (GZK cutoff energy) after traveling a distance of approximately 50 Mpc. For other hand, Albert Einstein wrote in a research article: “Does the inertia of a body depend on its energy content?” (Ist die Tragheit eines Korpers von seimen Energienhalt abhangig?): “If a body emits energy E in the form of radiation, its mass decreases by E/c2”. Thus, Maxwell's theory shows that electromagnetic waves are radiated whenever charges accelerate as for example for the electron. Then, this electromagnetic radiation (photons) produces a decrease in the mass of the electron which is given by the formula of the Variant Mass for an Accelerated Charged Particle which was demonstrated by me at this research [34] and at the research of the Variant Mass of the Electron at the Atom. This is true for any type of radiation emitted: electromagnetic or gravitational energy which produce a decrease in the mass of the body. Therefore, other objective of this article is to demonstrate the discovered formula which describes exactly the variant mass for a particle which emits gravitational energy. An example of the effect of this Gravitational energy emission is the light deflection for the light passing close the Sun (gravitational redshift frequency) and the Perihelion Precession of Mercury. Thus, the results of the mass formula are of great relevance for Gravitational Interactions. The results are in accordance with the classic result for the emission of the total gravitational energy (bond total energy) for a particle orbiting a large Planet or Sun and for a Binary Star. It is in agreement with the experiment result and with the Theory of General Relativity.

Ultraviolet suppression and nonlocality in optical model potentials for nucleon-nucleus scattering

We investigate the role of high momentum components of optical model potentials for nucleon-nucleus scattering and its incidence on their nonlocal structure in coordinate space. The study covers closed-shell nuclei with mass number in the range $4\leq A\leq 208$, for nucleon energies from tens of MeV up to 1 GeV. To this purpose microscopic optical potentials are calculated using density-dependent off-shell $g$ matrices in Brueckner-Hartree-Fock approximation and based on Argonne $v_{18}$ as well as chiral 2$N$ force up to next-to-next-to-next-to-leading order. We confirm that the gradual suppression of high-momentum contributions of the optical potential results in quite different coordinate-space counterparts, all of them accounting for the same scattering observables. We infer a minimum cutoff momentum $Q$, function of the target mass number and energy of the process, that filters out irrelevant ultraviolet components of the potential. We find that when ultraviolet suppression is applied to Perey-Buck nonlocal potential or local Woods-Saxon potentials, they also result nonlocal with similar appearance to those obtained from microscopic models in momentum space. We examine the transversal nonlocality, quantity that makes comparable the intrinsic nonlocality of any potential regardless of its representation. We conclude that meaningful comparisons of nonlocal features of alternative potentials require the suppression of their ultraviolet components.

Uncertainty of three-nucleon continuum observables arising from uncertainties of two-nucleon potential parameters

We investigate the impact of statistical uncertainties in the two-nucleon potentials on the neutron–deuteron elastic scattering and the deuteron breakup reaction observables at incoming nucleon kinetic energy up to 200 MeV. To that end we use the semi-phenomenological one-pion-exchange- Gaussian two-nucleon potential developed by the Granada group and the recent semi-local momentum-space regularized chiral nucleon–nucleon interaction at various orders, neglecting the three-nucleon force present in the three-nucleon system. The magnitudes of statistical uncertainties for these two potentials are found to be rather similar. For the chiral potential, we also show truncation errors estimated, among others, using the Bayesian method and discuss the residual cutoff dependence. The statistical uncertainty is generally found to be smaller than the truncation errors except for certain observables calculated at high chiral orders at nucleon energies up to 65 MeV. In general, magnitudes of the theoretical uncertainties are small and amount up to 0.5%–4%, depending on the observable and energy.

Direct photon emission and influence of dynamical wave packets in an extended quantum molecular dynamics model

Direct photon produced from first proton-neutron ($p$-$n$) collision during the early stage of heavy ion reaction is a sensitive probe to reflect energy and momentum distribution of nucleons. In this work, we embedded the hard photon production channel in an extended quantum molecular dynamics (EQMD) model, and took the direct photon as a possible probe to improve namely the Fermi motion in the EQMD model. A possible scheme is offered to handle the dynamical wave packet width within incoherent bremsstrahlung process. Direct photons calculated by our modified EQMD were compared with data of $^{14}$N + $^{12}$C at beam energies $E/A$ = 20, 30 and 40 MeV, and it is found that the yield, inverse slope and angular distribution of direct photons could be reasonably reproduced. In addition, asymmetric reaction systems of $^{4}$He + C and $^{4}$He + Zn at $E/A$ = 53 MeV are also simulated in this work. It is found that the symmetric angular distribution in the nucleon-nucleon ($N$-$N$) center-of-mass (c.m.) frame and the velocity of $ the \gamma$-emission source can be reasonably obtained from our method although there is some quantitative differences.

Nuclear effective field theory: Status and perspectives

The nuclear physics landscape has been redesigned as a sequence of effective field theories (EFTs) connected to the Standard Model through symmetries and lattice simulations of Quantum Chromodynamics (QCD). EFTs in this sequence are expansions around different low-energy limits of QCD, each with its own characteristics, scales, and ranges of applicability regarding energy and number of nucleons. We review each of the three main nuclear EFTs -- Chiral, Pionless, Halo/Cluster -- highlighting their similarities, differences, and connections. In doing so, we survey the structural properties and reactions of nuclei that have been derived from the ab initio solution of the few- and many-body problem built upon EFT input.

Magnetic polarizability of the nucleon using a Laplacian mode projection

Conventional hadron interpolating fields, which utilise gauge-covariant Gaussian smearing, are ineffective in isolating ground state nucleons in a uniform background magnetic field. There is evidence that residual Landau mode physics remains at the quark level, even when QCD interactions are present. In this work, quark-level projection operators are constructed from the $SU(3) \times U(1)$ eigenmodes of the two-dimensional lattice Laplacian operator associated with Landau modes. These quark-level modes are formed from a periodic finite lattice where both the background field and strong interactions are present. Using these eigenmodes, quark-propagator projection operators provides the enhanced hadronic energy-eigenstate isolation necessary for calculation of nucleon energy shifts in a magnetic field. The magnetic polarisability of both the proton and neutron is calculated using this method on the $32^3 \times 64$ dynamical QCD lattices provided by the PACS-CS Collaboration. A chiral effective-field theory analysis is used to connect the lattice QCD results to the physical regime, obtaining magnetic polarisabilities of $\beta^p = 2.79(22)({}^{+13}_{-18}) \times 10^{-4}$ fm$^3$ and $\beta^n = 2.06(26)({}^{+15}_{-20}) \times 10^{-4}$ fm$^3$, where the numbers in parantheses describe statistical and systematic uncertainties.

Using the HIJING Model in Modeling Nucleus–Nucleus Interaction at Energies of Nucleon–Nucleon Collisions 5–15 GeV

A new set of HIJING model parameters is found. Changes in the model are proposed that allow NA49 and NA61/SHINE experimental data on pp interactions to be described at projectile proton momenta $${{p}_{{{\text{lab}}}}}$$ = 20, 31, 40, 80 and 158 GeV c−1 in the rest frame of target protons. The modified model is used to analyze data on nucleus–nucleus interaction. It is shown that the model allows the main properties of these interactions to be described.

Using DIRHB package to calculate the properties of some nuclei

In this work, the relativistic Hartree-Bogoliubov method is studied for calculating of nuclear properties such as binding energy per nucleon, charge radii, and single-particle energies of proton and neutron for some nuclei like O16, Ca40, Sn132 and Pb208. This method is the relativistic case of the Hartree-Fock-Bogoliubov method, which is a generalization of the Hartree-Fock method, and the method includes short-range correlations such as pairing force. In addition, the energy functional DD-ME2 is used to describe the effective interactions in equations of the relativistic Hartree-Bogoliubov method. The DIRHB package, which was written in Fortran, is utilized to calculate and get the results. The results are compared with experimental ones, except the single-particle energies of Ca40 due to the lack of data. The comparisons show well agreements between the calculation results and the experimental values of binding energy per nucleon as well as charge radii, for parameters of the DD-ME2 which were fitted based on the experimental data of nuclear mass. However, the results of single-particle levels do not agree with experimental ones in some cases. This means the relativistic Hartree-Bogoliubov method should be studied further in the future.

Nuclear structure properties and decay rates of molybdenum isotopes

Electron capture and $\beta ^{-}$ decay are the dominant decay processes during late phases of evolution of heavy stars. Previous simulation results show that weak rates on isotopes of Molybdenum (Mo) have a meaningful contribution during the development of phases of stars before they go supernova. The relative abundance coupled with the stellar weak rates on Mo isotopes may change the lepton-to-baryon content of the core material. Here we report on the calculation of nuclear structure properties of 82−138Mo isotopes employing the RMF model. Later we calculate the weak decay rates of these isotopes. We use the pn-QRPA model to compute these rates. In the first step, the ground-state nuclear properties of Mo isotopes such as binding energy per nucleon, neutron and proton separation energies, charge radii, total electric quadrupole moments and deformation parameter of electric quadrupole moments have been calculated using density dependent version of RMF model with DD-PC1 and DD-ME2 functionals. The calculated electric quadrupole deformation parameters have been used in a deformed pn-QRPA calculation in the second phase of this work to calculate half-lives and weak decay rates for these Mo isotopes in stellar matter. We calculate the electron capture and $\beta $-decay rates over an extensive range of temperature ($0.01\times 10^{9}$ K to $30\times 10^{9}$ K) and density (10 to $10^{11}$) g/cm3. Our study can prove useful for simulation of presupernova evolution processes of stars.

The computational challenge of lattice chiral symmetry - Is it worth the expense?

The origin of the low-lying position of the Roper resonance in the nucleon energy spectrum has been the subject of significant interest for many years, including several investigations using lattice QCD. It has been claimed that chiral symmetry plays an important role in our understanding of this resonance. We present results from our systematic examination of the potential role of chiral symmetry in the low-lying nucleon spectrum through the direct comparison of the clover and overlap fermion actions. After a brief summary of the background motivation, we specify the computational details of the study and outline our comparison methodologies. We do not find any evidence supporting the claim that chiral symmetry plays a significant role in understanding the Roper resonance on the lattice.

INTERNATIONAL NUCLEAR DATA CENTERS NETWORK AND PROSPECTS OF ITS USE IN NUCLEAR POWER IN BELARUS

We give a brief overview of the existing nuclear data base, and describe the structure of the International Nuclear Data Centres Network. Because the amount of experimental data in nuclear physics is extremely large, the note aims to show the way to modern methods of acquaintance with the char- acteristics of arrays of nuclei through the nuclear data banks accessible through the Web-technologies. In particular, the note describes the methods to extract information on the nuclei and nuclear reactions in nuclear data banks. The data include information on the masses and energies of the nuclei of the separation energy of nucleons and clusters, the spectra of states of nuclei, their spin, parity, isospin, charge and mass radii and densities, information about the shape of the nuclei, the cross sections of nuclear reactions, the decay of unstable nuclei. On the completeness and accuracy of the data depends on radiation and nuclear safety, and environmental acceptability of nuclear installations. Creating a nuclear databases in Belarus will monitor the quality of nuclear data supplied to consumers, and ensure that systems of constants, used in technical projects, the current international standards.

Challenging microscopic structure and reaction models for nucleon scattering off nuclei in the A=208 mass region

We present a microscopic description of neutron and proton elastic and inelastic scattering off $^{206,207,208}\mathrm{Pb}$ and $^{209}\mathrm{Bi}$ together with new medium-energy (7.5--15.5 MeV) neutron elastic and inelastic scattering measurements for various low-energy levels. The Jeukenne, Lejeune, Mahaux (JLM) semimicroscopic folding model provides the relevant optical and transition potentials used to calculate the elastic and inelastic cross sections. Rearrangement corrections that account for proton and neutron density variations during the transition are considered. The nuclear diagonal and transition densities are calculated from a (quasiparticle) random phase approximation [(Q)RPA] structure model implemented with the Gogny D1S interaction. Calculated differential elastic and inelastic cross sections are mostly in very good agreement with available data. Predicted nuclear structure properties as well as scattering calculations and measurements for the yrast quadrupole excitation in $^{206}\mathrm{Pb}$ are carefully discussed. The rearrangement corrections to inelastic scattering form factors are shown to reduce medium energy nucleon inelastic cross section by up to 55%. The magnitude of these corrections changes depending on the probe, incident energy, multipolarity, and nature of the transitions considered. The combined analysis of nuclear structure properties and those for nucleon scattering cross sections measured previously over a range of incident energies provides stringent tests of present microscopic models and helps distinguish those scattering data which most likely call for revision.

Kompaneets equation for neutrinos: Application to neutrino heating in supernova explosions

Abstract We derive a “Kompaneets equation” for neutrinos, which describes how the distribution function of neutrinos interacting with matter deviates from a Fermi–Dirac distribution with zero chemical potential. To this end, we expand the collision integral in the Boltzmann equation of neutrinos up to the second order in energy transfer between matter and neutrinos. The distortion of the neutrino distribution function changes the rate at which neutrinos heat matter, as the rate is proportional to the mean square energy of neutrinos, $E_\nu^2$. For electron-type neutrinos the enhancement in $E_\nu^2$ over its thermal value is given approximately by $E_\nu^2/E_{\nu,\rm thermal}^2=1+0.086(V/0.1)^2$, where $V$ is the bulk velocity of nucleons, while for the other neutrino species the enhancement is $(1+\delta_v)^3$, where $\delta_v=mV^2/3k_{\rm B}T$ is the kinetic energy of nucleons divided by the thermal energy. This enhancement has a significant implication for supernova explosions, as it would aid neutrino-driven explosions.

Nd-Scattering within MGL Approach for Configuration-Space Faddeev Equations

We study the neutron-deuteron elastic and breakup scattering on the basis of the configuration-space Faddeev equations. The Merkuriev–Gignoux–Laverne approach has been generalized for arbitrary nucleon-nucleon potentials and with an arbitrary number of partial waves. Neutron-deuteron observables at the incident nucleon energy 14.1 MeV are calculated using the realistic AV14 nucleon-nucleon potential. Results are compared with those of other authors and with experimental neutron-deuteron scattering data. The computational procedure is presented in details.

ЭЛЕКТРОСИЛЬНОЕ ВЗАИМОДЕЙСТВИЕ

This work is devoted to the theoretical research of the electrical interaction between two dipoles having revealed "dipole effect", and studies of the electrical interactions in neutron-neutron and neutron-proton doublet of atomic nuclei. The possible structures of neutron-neutron and neutron-proton doublets were revealed. Research has shown that the strong nuclear interaction of nucleons is electrical in nature. The analysis of the possible reasons of discrepancies between theoretical calculations and experimentally obtained results of the binding energy of paired nucleons was executed. The plausible reasons for the existence of isomers are expressed.

Density Distributions and Elastic Electron Scattering Form Factors of Proton-rich 8B, 17F, 17Ne, 23Al and 27P Nuclei

In this work, the nuclear density distributions, size radii and elastic electron scattering form factors are calculated for proton-rich 8B, 17F, 17Ne, 23Al and 27P nuclei using the radial wave functions of Woods-Saxon potential. The parameters of such potential for nuclei under study are generated so as to reproduce the experimentally available size radii and binding energies of the last nucleons on the Fermi surface.

Toward a First-Principles Calculation of Electroweak Box Diagrams.

We derive a Feynman-Hellmann theorem relating the second-order nucleon energy shift resulting from the introduction of periodic source terms of electromagnetic and isovector axial currents to the parity-odd nucleon structure function F_{3}^{N}. It is a crucial ingredient in the theoretical study of the γW and γZ box diagrams that are known to suffer from large hadronic uncertainties. We demonstrate that for a given Q^{2} one only needs to compute a small number of energy shifts in order to obtain the required inputs for the box diagrams. Future lattice calculations based on this approach may shed new light on various topics in precision physics including the refined determination of the Cabibbo-Kobayashi-Maskawa matrix elements and the weak mixing angle.

Σ hyperons in nuclear collisions at energy of few GeV/c

The perspectives of identifying and studying the mechanisms of Σ hyperons production (isotopic and charged ratios) at the Nuclotron are discussed. The study of ion-ion interactions at few GeV/c per nucleon energy is interesting for searching new a phenomena and phase transitions at high baryonic densities and moderate temperatures of nuclear matter. In this paper, the possible extension of physical program of the planned measurements is considered.