Nucleon Configurations Research Articles

Study of clusters and hypernuclei production within PHSD+FRIGA model

We report on the results on the dynamical modelling of cluster formation with the new combined PHSD+FRIGA model at Nuclotron and NICA energies. The FRIGA clusterization algorithm, which can be applied to the transport models, is based on the simulated annealing technique to obtain the most bound configuration of fragments and nucleons. The PHSD+FRIGA model is able to predict isotope yields as well as hypernucleus production. Based on present predictions of the combined model we study the possibility to detect such clusters and hypernuclei in the BM@N and MPD/NICA detectors.

Study of Clusters and Hypernuclei production within PHSD+FRIGA model

We report on the results on the dynamical modelling of cluster formation with the new combined PHSD+FRIGA model at Nuclotron and NICA energies. The FRIGA clusterisation algorithm, which can be applied to the transport models, is based on the simulated annealing technique to obtain the most bound configuration of fragments and nucleons. The PHSD+FRIGA model is able to predict isotope yields as well as hyper-nucleus production. Based on present predictions of the combined model we study the possibility to detect such clusters and hypernuclei in the BM@N and MPD/NICA detectors.

Photo-absorption sum rules σ–1 in different environments (Atoms, nuclei, nucleons)

Combining the spin-dependent dispersion GDH-sum rule, the isotopic-spin-dependent Cabibbo-Radicati sum rule, and the relativistic dipole-moment-fluctuation (i.e. generalized Gottfried) sum rule with the three valence quark configuration of nucleons taken into account for the composition of the ground and the excited states of the nucleon, the relevant moments of the distribution and correlation functions of the quark electric dipole moment operators in the nucleon ground state are expressed via the experimentally measurable nucleon resonance photo-excitation amplitudes.These functions are of interest for checking detailed quark-configuration structure of the nucleon state vector. Within the non-relativistic approach to photo-absorption sum rules for the 3N-nuclei a new σ–1 sum rule proposed which is based on general charge-symmetry (CS) consequences for the “CS-conjugated” triton and 3He.

Multiple many-particle chiral systems described within the particle-rotor model

The multi-particle-plus-triaxial-rotor (MPR) model calculations were performed for several nuclei in the 100, 130 and 190 mass regions. Multiple chiral systems associated with many-particle nucleon configurations were found, but they may not necessarily form pairs of near-degenerate bands in an obvious way. Excited chiral systems may exhibit better near-degeneracy than the yrast one. Projections of the angular momenta along the nuclear axes were examined to study the nature of the chiral bands.

Photo-absorption sum rules σ−1 in different environments

Combining the spin-dependent dispersion GDH-sum rule, the iso-vector, photo-excitation states projecting Cabibbo-Radicati sum rule, and the relativistic dipole-moment-fluctuation (or generalized Gottfried) sum rule with the three valence quark configuration of nucleons taken into account for the composition of the ground and the excited states of the nucleon, the relevant moments of the distribution and correlation functions of the quark electric dipole moment operators in the nucleon ground state are expressed via the experimentally measurable nucleon resonance photo-excitation amplitudes.These functions are of interest for checking detailed quark-configuration structure of the nucleon state vector.

Effect of breakup and transfer on complete and incomplete fusion in6Li+209Bi reaction in multi-body classical molecular dynamics calculation

The effect of breakup and transfer in 6 Li+209 Bi reaction is studied in a multi-body classical molecular dynamics approach in which the weakly-bound projectile 6 Li is constructed as a 2-body cluster of 4 He and 2 H in a configuration corresponding to the observed breakup energy. This 3-body system with their individual nucleon configuration in their ground state is dynamically evolved with given initial conditions using Classical Rigid Body Dynamics (CRBD) approach up to distances close to the barrier when the rigid-body constraint on the target, inter-fragment distance, and 2 H itself are relaxed, allowing for possible breakup of 2 H which may result in incomplete fusion following the transfer of the n or p . Relative probabilities of the possible events such as scattering with and without breakup, DCF, SCF, ICF(x ) where x may be 4 He, 2 H, 4 He+n , 4 He+p , n , p are calculated. Comparison of the calculated event-probabilities, complete, and incomplete fusion cross sections with the calculation in which 2 H is kept rigid demonstrates the effect of the transfer reactions on complete and incomplete fusion in the 4-body reaction. Events ICF(4 He+n ) corresponding to nstripping followed by breakup of the resultant 5 Li to 4 He+p are found to contribute significantly in the fusion process in agreement with a recent experimental observation of direct reaction processes in breakup of weakly-bound projectiles.

Study of clusters and hypernuclei production with the NICA/MPD experiment

Heavy-ion collisions provide the unique possibility to create and investigate hot and dense matter in the laboratory. At the initial stage of the reaction a QGP is formed, while the final stage is driven by the hadronization process and the formation of clusters. The capture of the produced hyperons by clusters of nucleons leads to the hypernuclei formation which is a very rare process at strangeness threshold energies. We report on the first results on the dynamical modeling of cluster formation with the combined PHSD + SACA (Parton–Hadron–Strings dynamics + Simulated Annealing Clusterization Algorithm) model at Nuclotron and NICA energies. The clusters selection in SACA is realized by a simulated annealing procedure to obtain the most bound configuration of fragments and nucleons. Based on present predictions of the combined model we study the possibility to detect such clusters and hypernuclei in the NICA/MPD detector.

Candidate magnetic rotation sequence in 86Sr

High-spin states in 86Sr have been investigated by using in-beam γ ray spectroscopy with the 82Se(9Be, 5n)86Sr reaction at a beam energy of 53 MeV. A new dipole sequence has been observed and the mixed configurations of unpaired valence nucleons and before the alignment and the configuration after the alignment are assigned respectively. Shell-model and self-consistent titled axis cranking relativistic mean-field model calculations are performed to interpret the rotational structure and the characteristic features of magnetic rotation have been presented for the sequence.

Classical molecular dynamics simulation of weakly-bound projectile heavy-ion reactions

A 3-body classical molecular dynamics approach for heavy-ion reactions involving weakly bound projectiles is developed. In this approach a weakly bound projectile is constructed as a two-body cluster of the constituent tightly bound nuclei in a configuration corresponding to the observed breakup energy. This 3-body system with their individual nucleon configuration in their ground state is dynamically evolved for given initial conditions using the three-stage classical molecular dynamics approach (3S-CMD). Various levels of rigidbody constraints on the projectile constituents and the target are considered at appropriate stages. This 3-dimensional approach explicitly takes into account not only the long range Coulomb reorientation of the deformed collision partner but internal excitations and breakup probabilities at distances close to the barrier also. Dynamical simulations of ^6Li+^209Bi show all the possible reaction mechanism like complete fusion, incomplete fusion, scattering and breakup scattering. Complete fusion cross sections of ^6Li+^209Bi and ^7Li+^209Bi reactions are calculated in this approach with systematic relaxations of the rigid-body constraints on one or more constituent nuclei.

Multiple Chiral Bands Associated with the Same Strongly Asymmetric Many-particle Nucleon Configuration

Multiple Chiral Bands Associated with the Same Strongly Asymmetric Many-particle Nucleon Configuration

Collective flow in ultrarelativistic 3He–Au collisions

The triangular flow in ultrarelativistic 3He–Au collisions at RHIC energies is enhanced due to the triangular arrangement of the nucleon configurations in 3He. We study the fireball eccentricities in the Glauber Monte Carlo model and find that since the configurations of the projectile 3He are elongated triangles, the created fireball has not only a significant triangularity but also a large ellipticity. The dependence of the triangularity on centrality is weak, so it cannot be extracted from the centrality dependence of the triangular flow v3, as it is dominated by the centrality dependence of the hydrodynamic response. We propose to look at the centrality dependence of the ratio vn{4}/vn{2}, where the uncertainties from the hydrodynamic response cancel, and show that the basic signature of the geometry-driven collective flow is the rise of the ratio v3{4}/v3{2} with the number of participant nucleons for centralities less than 10%.

Inclusive and Exclusive Scatterings from Tensor Polarized Deuteron

The possibility of using a tensor polarized deuteron target in electroproduction reactions creates new opportunities for studying different phenomena related to the short-range hadronic and nuclear physics. The use of the tensor polarized deuteron allows us to isolate smaller than average inter-nucleon distances for the bound two-nucleon system. In this report we consider several high Q2 reactions which are particularly sensitive to the short-range two- nucleon configurations in the deuteron. One is the relativistic dynamics of electron-bound- nucleon scattering, which can be studied in both inclusive and exclusive reactions, and the other is the strong final state interaction in close proximity of two nucleons that can be used as a sensitive probe for color-transparency phenomena.

6Li(18O, 17O)7Li reaction and comparison of 6, 7Li+16, 17, 18O potentials

Abstract Angular distributions of the 6Li(18O, 17O)7Li reaction were measured at E lab ( O 18 ) = 114 MeV for ground and excited states of the exit channel nuclei for the first time. The data were analyzed within the coupled-reaction-channels method (CRC). The 6Li + 18O elastic and inelastic scattering channels as well as simplest one- and two-step reactions were included in the coupled-reaction-channels scheme. The 7Li + 17O potential was deduced by fitting CRC calculations to the reaction data. The spectroscopic amplitudes for single nucleon and nuclear cluster configurations were calculated within the translationally invariant shell model. Isotopic differences of the 7Li + 16, 17, 18O and 7, 8Li + 17O potentials and the reaction mechanisms were studied.

The dipole model Monte Carlo generator Sartre 1

We present the Monte Carlo generator Sartre for simulating diffractive exclusive vector meson production and DVCS in electron–proton, electron–ion, and hadron–hadron collisions. Program summaryProgram title: Sartre 1.0Catalogue identifier: AESP_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AESP_v1_0.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: GNU General Public License, version 2No. of lines in distributed program, including test data, etc.: 703313No. of bytes in distributed program, including test data, etc.: 179406465Distribution format: tar.gzProgramming language: C/C++.Computer: Any with standard C/C++ compiler.Operating system: Tested on Linux and MacOS.Classification: 11.1, 11.2, 11.6.External routines: ROOT and GSL for numeric algorithms and other various tasks throughout the program. BOOST for multi-threaded integration (optional), GEMINI++ for nuclear break-up and CUBA for multi-dimensional numerical integration (the latter two supplied with the program package). Uses cmake for building and installing.Nature of the problem:Simulate diffractive exclusive vector meson and deeply virtual Compton scattering (DVCS) production in electron–nucleus scattering where the exchanged virtual photon interacts coherently with a large region of the nucleus. To calculate the cross section correctly it has to be averaged over all possible configurations of nucleon positions within the nucleus.Solution method:To make an arithmetic average of the quantum mechanical amplitude over nucleon configurations numerically and store the result in look-up tables.Implemented processes: The following processes can be simulated: e+p→e′+V+p′e+A→e′+V+A′p+p→p′+V+p′p+A→p′+V+A′(1)A+A→A′+V+A′ where V is a J/ψ,φ, or ρ vector meson, or a real photon (DVCS). All processes are mediated by a virtual photon and a pomeron. The present version is applicable for these processes at future electron–hadron colliders, such as the EIC and the LHeC, as well as HERA, RHIC, and the LHC.Restrictions:The program is reliable for process at xp<10−2, and large β=x/xp.Additional comments:The distribution file for this program is over 178 MB and therefore is not delivered directly when download or E-mail is requested. Instead an html file giving details of how the program can be obtained is sent.Running time:On a MacBook Pro with a 2.66 GHz Intel Core i7 processor, event generation takes ∼0.1 ms/event without correction and nuclear breakup, ∼0.2 ms/event with the recommended corrections switched on, and ∼6 ms/event when running with corrections and nuclear breakup.

Imposing Fermi momentum cut-off on the channel- and density-dependent effective interaction and the ground-state properties of closed shell nuclei

The ground-state properties of light-moderate symmetric closed shell nuclei, i.e. 4He, 12C, 16O, 28Si, and 40Ca, and moderate-heavy asymmetric ones, i.e. 48Ca, 90Zr, and 120Sn, are calculated using the channel- and density-dependent effective interaction with the imposed Fermi momentum cut-off (CDDEI+FMC). CDDEI+FMC are generated through the lowest-order constrained variational (LOCV) nuclear matter calculations with the $ Av_{18}(j_{max}=2)$ nucleon-nucleon bare potential. FMC is considered by defining the maximum value of the relative quantum numbers according to the last shell in the ground state of a nucleus. The Hamiltonian matrix of the truncated effective interactions is diagonalized in the harmonic oscillator basis, regarding the nucleon configurations. The FMC effect on the different interaction channels is considered by comparing the contributions of each channel in the binding energies of the sample nuclei. CDDEI+FMC are replaced by the density-dependent average effective interactions with the imposed FMC (DDAEI+FMC) for the channels with $ j > j_{max}$ . For the light nuclei, the results show that the nuclei are more binding relative to the CDDEI-FMC case. The 4He nucleus is about 1.4MeV more binding per nucleon, and the root mean square of its radius equals the experimental data exactly. For the moderate-heavy closed shell nuclei, there are no significant differences between the results of the two cases, both with FMC and without it.

Can a Chiral System Be Built on a Strongly Asymmetric Nucleon Configuration?

The multi-particle-plus-triaxial-rotor (MPR) model calculations were performed for several nuclei in the 100, 130 and 190 mass regions. It was found that chiral geometry can form even for very asymmetric nucleon configurations. However, the near-degeneracy of the partner bands may not be as good as the one observed for symmetric or slightly asymmetric configurations. DOI:10.5506/APhysPolB.44.341

Photoproduction of π + p pairs on nuclei

The photoproduction of pion-nucleon pairs on nuclei was analyzed. The contributions of both nucleonic and isobar configurations in the ground state of nuclei were taken into account. The cross section for the photoproduction of pion-proton pairs in the reactions 16O(γ, π+p)15C and 12C(γ, π+p)11Be were calculated.

Nuclear density matrix of the A(γ,πN)B process

Expressions for the one- and two-particle density matrices of nuclei are derived with allowance for the nucleon and isobar configurations. Mechanisms of photoproduction of pion-nucleon pairs corresponding to individual components of the density matrices are considered.

Multi-kaonic Hypernuclei and Kaon Condensation

This contribution reports on dynamical, self-consistent calculations of multi-K̄ hypernuclei, which were performed by adding antikaons to particle-stable nuclear configurations of nucleons, Λ and Ξ hyperons. Our results show a robust pattern of saturation of the K̄ separation energy BK̄ as a function of the number of K̄ mesons, with BK̄ bounded from above by 200 MeV. The associated baryon densities saturate at values 2-3 times nuclear-matter density. The main reason for saturation is the repulsion induced by the vector meson fields between K̄ mesons, similarly to what was found for multi-K̄ nuclei. The calculations confirm that strangeness in finite strong-interaction self-bound systems is realized through hyperons, with no room for kaon condensation.

Solution of the Skyrme–Hartree–Fock–Bogolyubov equations in the Cartesian deformed harmonic-oscillator basis.: (VII) hfodd (v2.49t): A new version of the program

We describe the new version (v2.49t) of the code HFODD which solves the nuclear Skyrme Hartree-Fock (HF) or Skyrme Hartree-Fock-Bogolyubov (HFB) problem by using the Cartesian deformed harmonic-oscillator basis. In the new version, we have implemented the following physics features: (i) the isospin mixing and projection, (ii) the finite temperature formalism for the HFB and HF+BCS methods, (iii) the Lipkin translational energy correction method, (iv) the calculation of the shell correction. A number of specific numerical methods have also been implemented in order to deal with large-scale multi-constraint calculations and hardware limitations: (i) the two-basis method for the HFB method, (ii) the Augmented Lagrangian Method (ALM) for multi-constraint calculations, (iii) the linear constraint method based on the approximation of the RPA matrix for multi-constraint calculations, (iv) an interface with the axial and parity-conserving Skyrme-HFB code HFBTHO, (v) the mixing of the HF or HFB matrix elements instead of the HF fields. Special care has been paid to using the code on massively parallel leadership class computers. For this purpose, the following features are now available with this version: (i) the Message Passing Interface (MPI) framework, (ii) scalable input data routines, (iii) multi-threading via OpenMP pragmas, (iv) parallel diagonalization of the HFB matrix in the simplex breaking case using the ScaLAPACK library. Finally, several little significant errors of the previous published version were corrected.