A comparative analysis of the density distributions and the structure models of <Superscript>9</Superscript>Li

In the present study, we have analysed the elastic scattering cross-section data of ⁹Li + ¹²C system at E _lab = 540 MeV and ⁹Li + ²⁰⁸Pb system at E _c.m. = 28.3 MeV for some cluster models and various density distributions of the ⁹Li nucleus. First, we have obtained five different density distributions of the ⁹Li nucleus to generate real potentials with the help of double-folding model. For these densities, we have calculated the elastic scattering angular distributions. Secondly, using a simple approach, we have investigated some cluster models of the ⁹Li nucleus consisting of ⁶He + ³H and ⁸Li + n systems. We have presented the comparison of elastic scattering angular distributions for each system with each other as well as with the experimental data. Finally, we have given the cross-section values obtained from the theoretical calculations for all the systems studied in this paper.     

Phase shift analysis of the <Superscript>6</Superscript>He+<Superscript>208</Superscript>Pb and the <Superscript>6</Superscript>He+<Superscript>197</Superscript>Au systems

We present the elastic scattering of the ⁶He+²⁰⁸Pb and the ⁶He+¹⁹⁷Au systems at the laboratory energy of E _lab=27 MeV within the framework of the McIntyre parametrization, and systematically investigate χ ²/N analysis of both systems to obtain an excellent agreement between the theoretical results and the experimental data. We find large diffusivity parameters indicating long range absorption mechanisms. We also show that both systems lack both the nuclear and the Coulomb rainbow scattering for obtained S-matrix parameters.     

Heavy lithium isotope <Superscript>11,12</Superscript>Li production in pion absorption reactions on a <Superscript>14</Superscript>C radioactive target

The results from an experimental search for the production of heavy lithium isotopes ^11,12Li in stopped π⁻-meson absorption reactions on a ¹⁴C radioactive target are presented. A pronounced peak is observed in the missing mass spectrum of the ¹⁴C(π⁻, pp)X reaction, which is associated with the formation of a nucleon-unstable ¹²Li state with the following resonance parameters: E _R = 4.0 ± 0.2 MeV and Γ = 1.1 ± 0.2 MeV. Resonance parameters of three low-lying ¹¹Li excited states were determined in the ¹⁴C(π⁻, pd)X, reaction.     

Total strength of the magnetic dipole resonance in <Superscript>31</Superscript>P

The γ decay of the resonance-like structure observed in the ³⁰Si(pγ)³¹P reaction in the energy range E _p = 1.4–2.7 MeV of accelerated protons has been investigated. The excitation function of this reaction and the spectra and angular distributions of the γ rays formed in the decay of resonances with E _p = 1482, 2350, and 2505 keV have been measured. The M1 resonance on the ground and the first excited states of ³¹P with E _p = 1266 keV is identified. The total strength of the M1 resonance on the ground state of this nucleus is determined. The position and total strength of this resonance on the ground state are explained taking into account pairing forces.     

Semiclassical description of the <Superscript>6</Superscript>He+<Superscript>12</Superscript>C elastic scattering

The results of the elastic scattering of ⁶He+¹²C systemat E _Lab = 18 MeV by using the barrier and internal wave decomposition of the S-matrix element within the framework of the WKB method are presented. This is the first detailed study for the interaction of the exotic ⁶He nucleus on different stable nuclei by using a semiclassicalmethod. In this paper, we show that in order to obtain the elastic scattering cross section of the ⁶He+¹²C systemat energies close to the Coulomb barrier, it is vitally important to take into account the inner complex turning points in the calculations and the tunneling effects play a crucial role to explain the experimental data. The semiclassical results are compared with the experimental data as well as the quantum-mechanical one.     

Effect of the structure of neutron-rich <Superscript>8</Superscript>Li and <Superscript>9</Superscript>Li isotopes on the characteristics of proton elastic scattering

The differential cross sections of proton elastic scattering from ⁸Li and ⁹Li nuclei in inverse kinematics have been calculated. The cross sections were determined within the Glauber diffraction theory with the wave functions of nuclei in the three-particle α-t-n, α-t-2n, and ⁷Li-n-n models. Comparison with the existing experimental data for E = 700 and 60 MeV/nucleon made it possible to draw a conclusion about the quality of the wave functions and the adequacy of the potentials used for their calculations.     

Saturation of Coulomb sum rules in the <Superscript>6</Superscript>Li case

The Coulomb sums S _L(q) of the ⁶Li nucleus have been obtained from electron scattering measurements at 3-momentum transfers q = 1.125–1.625 fm⁻¹. It is found that at q > 1.35 fm⁻¹ the Coulomb sum of the nucleus becomes saturated: S _L(q) = 1 .     

Phase analysis of elastic <Emphasis Type="Italic">p</Emphasis><Superscript>6</Superscript>Li scattering at astrophysical energies

Based on new experimental investigations of elastic p ⁶Li scattering at energies 500–1150 keV and angles 30–170°, a phase analysis is performed and interaction potentials for p ⁶Li-system in ^2,4S- and ²P-states are constructed.     

Elastic scattering of6Li on6Li in the energy rangeE CM=2–10MeV

In a coincidence experiment, two excitation functions (0_cm=60° and 90°) and four angular distributions of the differential cross section for the elastic scattering of⁶Li on⁶Li were measured. The energy range for the excitation functions was from 2 to 10 MeV (CM), the angular distributions were taken at CM-energies of 4, 5, 6, 7.25 MeV. Optical model calculations were performed. It is shown that the outer portion of the potentials is most important for reproducing the experimental data.     

Transverse beam asymmetries measured from <Superscript>4</Superscript>He and hydrogen targets

The HAPPEX Collaboration at Jefferson Lab has measured the transverse beam spin asymmetries (A_T) for elastic electron scattering from proton and ⁴He targets. The experiment was conducted using a vertically polarized electron beam of energy ∼ 3 GeV, at a Q ² ∼ 0.1 GeV^2 and a scattering angle θ_lab ∼ 6^° . The preliminary results are reported here. The ⁴He measurement is the first measurement of A_T from a nucleus. A_T for ⁴He is non-negligible; therefore, it will be necessary to make measurements of A_T for future parity-violating experiments using nuclear targets.     

Spectroscopy of the <Superscript>10</Superscript>Li isotope in stopped pion absorption reactions on a <Superscript>14</Superscript>C radioactive target

A search for the ¹⁰Li formation was performed in missing mass spectra measured in stopped pion absorption reactions ¹⁴C(π ⁻, pt)X and ¹⁴C(π ⁻, dd)X. Three excited states of ¹⁰Li were found. The broad state with a resonance energy of E _R = 6.13 ± 0.11 MeV has the highest excitation energy in comparison with levels observed earlier.     

Channel coupling and exchange of an alpha-particle cluster in deuteron scattering on 6Li nuclei

Existing experimental data on elastic and inelastic deuteron scattering on ⁶Li nuclei in the energy range from 8 to 50 MeV were analyzed within the approach of coupled reaction channels. The coupling of elastic scattering and inelastic scattering accompanied by the transition to the 3⁺ state at E _x = 2.186 MeV and the mechanism involving the exchange of an alpha-particle cluster were taken into account in respective calculations. The phenomenological potentials obtained from the present analysis describe well experimental angular distributions at all energies and in full angular ranges. The depths of the real and imaginary parts of the potentials in question depend smoothly on energy at fixed values of the remaining parameters. The energy dependence of relevant volume integrals agrees well with similar data for the p + ⁶Li, ?? + ⁶Li, and ¹²C + ¹²C systems and with the predictions of a microscopic theory.     

Description of elastic scattering in the <Superscript>16</Superscript>O + <Superscript>16</Superscript>O and <Superscript>16</Superscript>O + <Superscript>12</Superscript>C systems

The objective of the present study was to describe more precisely experimental data on elastic scattering in the ¹⁶O + ¹⁶O system at E _lab = 124, 145, 250, 350, and 480 MeV and in the ¹⁶O + ¹²C system at E _lab = 132, 170, 181, 200, 230, 260, and 281 MeV. The role of exchange interaction in the region of backward angles is investigated. The coefficient of incompressibility of nuclear matter is estimated at K = 205 MeV ± 15%.     

Coupled-channels analysis of K<Superscript>+</Superscript> scattering from <Superscript>6</Superscript>Li and <Superscript>12</Superscript>C using the Watanabe superposition model

Coupled-channels calculations for the elastic and inelastic scattering of K⁺ at 715 MeV/c by ⁶Li and ¹²C at 635, 715 and 800 kaon Lab momenta have been analysed. The optical potentials of ¹²C and ⁶Li are calculated in terms of the alpha-particle and deuteron optical potentials. Good fits to the experimental data and phenomenological calculations are obtained for ⁶Li and ¹²C nuclei.     

Spectroscopy of the <Superscript>9</Superscript>Li isotope in stopped-pion absorption reactions

The origin of the ⁹Li isotope is sought in missing-mass spectra measured in ¹¹B(π⁻, d)X, ¹²C(π⁻, pd)X, and ¹⁴C(π⁻, dt)X stopped-pion absorption reactions. The parameters of the three observed low-lying excited states coincide with the literature data. A state with excitation energy E _x = 9.1 ± 0.1 MeV, lying above the threshold of ⁹Li decay into ⁶He + t, is observed for the first time.     

Interaction of intermediate-energy protons with <Superscript>20</Superscript>Ne and <Superscript>24</Superscript>Mg nuclei within the multiple-scattering model

Observables of the elastic and inelastic scattering of 800- and 250-MeV protons on ²⁰Ne and ²⁴Mg nuclei were calculated on the basis of the theory of multiple diffractive scattering and the dispersive α-cluster model. The ²⁰Ne and ²⁴Mg nuclei were assumed to consist of a core (¹⁶O nucleus) and additional alpha-particle clusters, which could be situated with the highest probability both in the vicinity of the center of mass of the core and outside the core. The multiparticle densities of these nuclei and single-particle nucleon-distribution densities as obtained from the dispersive α-cluster model were used in the calculations. The differential cross sections and polarizations for elastic and inelastic p ²⁰Ne and p ²⁴Mg scattering at the energy of 800 MeV are in better agreement with experimental data than the analogous calculations at the energy of 250 MeV. The spin-rotation functions calculated in the singleparticle approximation for elastic p ²⁰Ne and p ²⁴Mg scattering at these two energy values differ qualitatively from their counterparts calculated on the basis of the dispersive α-cluster model.     

Partial-wave analysis for elastic <Emphasis Type="Italic">p</Emphasis><Superscript>13</Superscript>C scattering at astrophysical energies

A standard partial-wave analysis was performed on the basis of known measurements of differential cross sections for elastic p ¹³C scattering at energies in the range 250–750 keV. This analysis revealed that, in the energy range being considered, it is sufficient to take into account the ³ S ₁ wave alone. A potential for the triplet ³ S ₁-wave state of the p ¹³C system in the region of the J ^p T = 1⁻¹ resonance at 0.55 MeV was constructed on the basis of the phase shifts obtained from the aforementioned partial-wave analysis.