Excited state production and temperature measurement in a heavy ion reaction

An effective temperature inferred from the slope of kinetic energy spectra of the emitted fragments is not reflected in the relative populations of excited states of the emitted nuclei. We found that the excited state populations of ⁶Li, ⁷Li and ⁷Be emitted near 90° in the lab from the reaction of 490 MeV ¹⁴N with Ag are significantly lower than those expected on the basis of their effective temperature.     

Study of 60Zn and 61Zn

The (¹²C, ¹⁰Be) and (¹²C, ⁹Be) reactions on ⁵⁸Ni were studied at 77 MeV. New levels were determined for both residual nuclei, ⁶⁰Zn and ⁶¹Zn. For ⁶¹Zn, levels and a new ground state mass were also measured with the ⁶⁴Zn(³He, ⁶He) reaction. A mass excess for ⁶¹Zn of ?56333±23 keV was obtained. Angular distributions for the ¹²C induced reactions are compared with finite range DWBA calculations and found to be insensitive to L? and J-transfer.     

Excitation of giant resonance in 90Zr by inelastic 6Li scattering

Inelastic ⁶Li scattering by ⁹⁰Zr was measured at 74 MeV. A broad structure, which appears to be the giant quadrupole resonance, was observed at 13.8 MeV excitation energy. This observation is in agreement with previous work done with ions lighter than ⁶Li.     

New Measurement of the π0 radiative decay width

High precision measurements of the differential cross sections for π0 photoproduction at forward angles for two nuclei, 12C and 208Pb, have been performed for incident photon energies of 4.9-5.5 GeV to extract the π0→γγ decay width. The experiment was done at Jefferson Lab using the Hall B photon tagger and a high-resolution multichannel calorimeter. The π0→γγ decay width was extracted by fitting the measured cross sections using recently updated theoretical models for the process. The resulting value for the decay width is Γ(π0→γγ)=7.82±0.14(stat)±0.17(syst) eV. With the 2.8% total uncertainty, this result is a factor of 2.5 more precise than the current Particle Data Group average of this fundamental quantity, and it is consistent with current theoretical predictions.     

The mass of 29S

the mass of ²⁹S has been measured with the ³²S(τ, ⁶He) reaction at 70 MeV. The mass excess is ?3.16 ± 0.05 MeV.     

First observation of the neutron-rich nuclei42Si,45, 46P,48S,and51Cl from the interaction of 44 MeV/u48Ca +64Ni

Five new very neutron-rich isotopes,⁴²Si,^45,46P,⁴⁸S and⁵¹Cl, are identified from the interaction of a 44 MeV/u⁴⁸Ca beam with a⁶⁴Ni target.     

A high resolution study of 26Al via the (p,d) reaction

Excitation energies and angular distributions of ²⁶Al levels in the first 6 MeV of excitation have been measured with the ²⁷Al(p, d)²⁶Al reaction at E_p = 35 MeV. Deuteron spectra were analyzed with an Enge split-pole magnetic spectrograph and recorded on nuclear emulsions (experimental resolution ≈ 6 keV, FWHM); supplementary data were recorded with position-sensitive wire proportional counters. The angular distributions were analyzed with the DWBA to extract the l-values and associated spectroscopic factors of the neutron transfers. The results for excitation energies, l-values, spectroscopic factors, and values of J^π, T are discussed in terms of previous experimental and theoretical work and in the light of new shell-model calculations for this system.     

Role of the RMS radius in DWBA calculations of the (p,d) reaction

The single-neutron pick-up reaction cross sections appear to be better correlated with the rms radius of the neutron orbit rather than with r₀, the radius parameter of the single-particle Woods-Saxon well. Form factors which correspond to particles bound by the experimental separation energies and which have rms radii for the $\text{2}\text{s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{, 1}\text{d}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{and}\text{1}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ orbits obtained from Coulomb energy shifts, lead to spectroscopic factors and S_>/S_< ratio for the ^46,48,50Ti(p, d) reactions which are in a much better agreement with theoretical expectations than those obtained with constant r₀.     

Analogue states in 47Ca

The ⁴⁸Ca(³He, ⁴He)⁴⁷Ca and ⁴⁸Ca(p, d)⁴⁷Ca reactions were used to observe six levels in ⁴⁷Ca above 12 MeV excitation. Analysis of the data has yielded precise excitation energies for the lowest $\text{T =}\text{9}\text{2}$ levels in ⁴⁷Ca; which are analogs of low-lying levels in ⁴⁷K. Comparison of experimental and calculated Coulomb displacement energies for the K-Ca isotopes is made.