Configuration of 3.59 MeV 0+ state in 44Ca

Results obtained with the ⁴⁸Ti(d, ⁶Li) reaction, at E_d = 55 MeV, establish the 3.59 MeV 0⁺ level of ⁴⁴Ca as virtually pure 8 p?4h, with T_h = 0.     

Coupled-channel fusion and inelastic scattering calculations for 18O + 44Ca and 12C + 48Ti

Fusion and inelastic scattering coupled-channel calculations are carried out for the systems ¹⁸O + ⁴⁴Ca and ¹²C + ⁴⁸Ti. Comparison between ¹²C + ⁴⁸Ti and ³²S + ²⁴Mg sub-barrier fusion cross-section enhancement is made using simple analytical expressions. The distribution of the angular momentum absorbed by the compound nucleus is discussed in a quantum-mechanical coupled-channel model.     

Interference effects in inelastic proton scattering on 28Si

Interference effects in ²⁸Si(p, p') inelastic scattering are studied in the Coulomb barrier region. The interference occurs between compound contributions and direct inelastic transitions. The asymmetric resonance shape is analysed to extract the intrinsic shape of the excited target nucleus.     

High resolution proton scattering from 42Ca

Differential cross sections were measured for ⁴²Ca(p, p) at four angles between E_p = 1.2 and 3.0 MeV, with an overall energy resolution of 325 eV. Spins, parities and proton widths were extracted for 170 resonances. Two analogue states were identified and spectroscopic factors determined. The nearest neighbor spacing distributions were analyzed. Proton strength functions were determined for $\text{1}\text{2}$⁺, $\text{1}\text{2}$^? and $\text{3}\text{2}$^? resonances.     

The mean life of the second 0+ state in 42Ca

The mean life of the second excited state in ⁴²Ca (1.84 MeV, O⁺) was measured by a direct electronic timing technique to be 558 ± 8 ps. This result compares with a previous measurement of 480 ± 30 ps which yields a high B(E2) value. The present result gives a B(E2; 0₂⁺ 1.84 MeV → 2₁⁺ 1.52 MeV) value of 484 e² · fm⁴ or 55 single-particle units; the theoretical implications of this are discussed.The accurate mean life was extracted using a convoluted function to describe both the inherent time resolution of the experimental system and the exponential decay of the state of interest.     

M1 states in 58Ni observed by proton inelastic scattering at 65 MeV

Inelastic proton scattering at 65 MeV was used to study 1⁺ states in ⁵⁸Ni. A new 1⁺ state was found at an excitation of 5.166 MeV. The angular distributions for the 1⁺ states at 2.903 and 5.166 MeV were well reproduced by a DWBA calculation under the assumptions of pure $\text{v(}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}\text{and}\text{v(}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{)}$ configurations, respectively. The angular distribution for the previously suggested 1⁺ state at 7.721 MeV was not well discribed by the DWBA calculation with the isoscalar $\text{(}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}$ wave function. The shape of the angular distribution for the 10.672 MeV, 1⁺ state was well reproduced by the DWBA calculation with the isovector $\text{(}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}$ wave function.     

The isospin forbidden 1− → 0+ transition in 40Ca

The isospin forbidden transition 1^? (6.95 MeV) → 0⁺ (g.s.) in ⁴⁰Ca is explained within a model that mixes isospin through single-particle energy differences and the two-body Coulomb interaction. There is no need to introduce an isospin non-conserving part of the nucleon-nucleon interaction to explain this anomalously fast transition.     

Elastic and inelastic scattering of 120 MeV 18O from 208Pb and the spin alignment of the 2+ state of 18O

The elastic and inelastic scattering of ¹⁸O ions at 120 MeV from a target of ²⁰⁸Pb have been studied. Cross sections for excitation of the 2⁺ state at 1.982 MeV in ¹⁸O and of the 3^? state at 2.61 MeV in ²⁰⁸Pb were measured. In addition, the populations of the m-substates for the ¹⁸O excitation were deduced from the Doppler-broadened line shapes. The data were subjected to a coupled-channels analysis using either Woods-Saxon or folding-model potentials. In addition, the ¹⁸O excitation was found to be described very well by use of a semi-microscopic model. The analyses consistently indicated the presence of a positive static hexadecapole moment of several e · fm⁴ for the 2⁺ state of ¹⁸O. The m-substate population distributions were found to be better fitted if a vector spin-orbit coupling was introduced for the 2⁺ state of ¹⁸O with a sign opposite to that for the nucleon-nucleus case.     

46.8MeV的p+12C非弹性散射

在Glauber多重散射理论框架下，使用跃迁密度方法和三种N湮没势，计算了46.8MeV的反质子在¹²C上的非弹性散射微分截面. 理论曲线与实验数据符合得较好. 关键词： Glauber理论 反质子 非弹性散射 湮没势 跃迁密度     

Wave functions of 0+ states in 42Ca

Ratios of cross sections in ⁴¹Ca(d,p) and ³⁸Ar(⁶Li,d) leading to 0⁺ states of ⁴²Ca allow determination of the coefficients in wave functions of the type a(2p)+b(4p?2h) + c(6p?4h), and an independent evaluation of the intrinsic amplitude for (sd)²(fp)² and (fp)⁴ α transfer.     

Wave functions of 0+ levels in 38Ca

A simple model of the first three 0⁺ levels in ³⁸Ca gives a good account of the excitation energies and (³He, n) cross sections. The hamiltonian derived is reasonable and the mixing is similar to that needed for other nearby nuclei.     

Pion photoproduction and inelastic scattering in A=12 nuclei: Transitions to the lowest isovector 1+ and 2+ levels

The continuity equation for the nuclear electric charge and convection current $\text{? ·}\text{j}\text{?}{}_{\mathrm{N}}\text{=}\text{?α}\text{ρ}\text{?}{}_{\mathrm{N}}\text{ρt}$ has been used in an analysis of nuclear transition densities in ¹²C. The results differ considerably from the former derivations. The standard M1 and newly-calculated E2 nuclear structure input is applied to estimate the pionic cross sections. A consistent improvement in several instances over the earlier results has been achieved; the calculations agree nicely with data both in the (3, 3) resonance region and at lower pion energies.     

Shell model study of 0+ states in 40Ca

Low-lying positive parity levels of calcium-40 are discussed in the framework of the shell model. An inert ³²S core is assumed, and $\text{Od}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ and $\text{Of}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ are taken as active orbits. As effective interactions we assumed those used by Federman and Pittel. Effect of many-particle and many-hole configurations up to 8p–8h states are shown to be important even for the very low-lying 0⁺ states.     

Generator-coordinate study of elastic 16O + 40Ca scattering

Elastic ¹⁶O + ⁴⁰Ca phase shifts are calculated using a generator-coordinate method. A rotational band of molecular resonances is found with a rotational constant of about 30 keV. The width of these resonances should make them observable in the energy range 30 to 50 MeV. These features can be approximately reproduced by a shallow local potential. Properties of the imaginary part of the optical potential are discussed qualitatively. The optical potential should be transparent in a window of J-values comprised between about 16 and 25. Odd-even effects are shown to be negligible in the real part of the potential but might be important in its imaginary part. A possible confirmation of these predictions is found in an experimental excitation function.     

A microscopic calculation of inelastic electron scattering to the first 2+ state in some even tin isotopes

We present a calculation of the inelastic electron scattering form factors to the first excited 2⁺ state in the even ^{116, 120, 124}Sn isotopes in the plane wave Born approximation. The states of the even tin isotopes are described in terms of one particle parentage coefficients, which have been obtained self-consistently for the pairing-plus-quadrupole model. The experimentally observed structure of the cross section is well reproduced but the magnitude of the cross section shows the need for a DWBA analysis.     

High resolution proton inelastic scattering from 50Cr

Resonances in the ⁵⁰Cr(p, p′γ) reaction were investigated with the TUNL high resolution system. All previously observed p-wave resonances between Ep = 2.00 and 3.03 MeV were studied. Measurement of the p' and the γ-ray angular distributions provides sufficient information to determine unambiguously the J-value of the resonance and the magnitude and relative phase of the inelastic decay amplitudes. Expressions are given for the appropriate angular distributions and for the transformation between the channel spin and the total angular momentum representation. Experimental results are presented for 24 p-wave resonances in ⁵¹Mn including decay amplitudes and relative phases for $\text{16}\text{3}\text{2}{}^{\mathrm{?}}$ resonances. Six resonances formerly assigned $\text{1}\text{2}{}^{\mathrm{?}}$ are reassigned $\text{3}\text{2}{}^{\mathrm{?}}$. Inelastic spectroscopic factors were determined for two analogue states. Proton strength functions were evaluated from both the elastic and inelastic data.     

The 6.05 MeV 0+ state in 16O: A shape isomer

A variational calculation predicts the existence of a quadrupole deformed isomeric state in ¹⁶O, which may be associated with the observed rotational band starting at 6.05 MeV. Calculated B(E2) value and strength in the ¹⁸O(p, t) reaction support this interpretation.