C. Scholl

Extraction of weak transition strengths via the (He-3, t) reaction at 420 MeV

Differential cross sections for transitions of known weak strength were measured with the (3He, t) reaction at 420 MeV on targets of 12C, 13C, 18O, 26Mg, 58Ni, 60Ni, 90Zr, 118Sn, 120Sn, and 208Pb. Using these data, it is shown that the proportionalities between strengths and cross sections for this probe follow simple trends as a function of mass number. These trends can be used to confidently determine Gamow-Teller strength distributions in nuclei for which the proportionality cannot be calibrated via beta-decay strengths. Although theoretical calculations in the distorted-wave Born approximation overestimate the data, they allow one to understand the main experimental features and to predict deviations from the simple trends observed in some of the transitions.

Alternative interpretation of sharply rising E0 strengths in transitional regions.

It is shown that strong 0(+)(2)-->0(+)(1) E0 transitions provide a clear signature of phase transitional behavior in finite nuclei. Calculations using the interacting-boson approximation (IBA) show that these transition strengths exhibit a dramatic and robust increase in spherical-deformed shape transition regions, that this rise matches well the existing data, that the predictions of these E0 transitions remain large in deformed nuclei, that they arise from the specific d-boson coherence in the wave functions, and do not necessarily require the explicit mixing of normal and intruder configurations from different IBA spaces.

Spectroscopy of 24 Al and extraction of Gamow-Teller strengths with the 24 Mg( 3 He,t) reaction at 420 MeV.

The {sup 24}Mg({sup 3}He,t){sup 24}Al reaction was studied at E({sup 3}He)=420 MeV. An energy resolution of 35 keV was achieved. Gamow-Teller strengths to discrete levels in {sup 24}Al were extracted by using a recently developed empirical relationship for the proportionality between Gamow-Teller strengths and differential cross sections at zero momentum transfer. Except for small discrepancies for a few weak excitations, good agreement with previous {sup 24}Mg(p,n) data and nuclear-structure calculations using the USDA/B interactions in the sd shell-model space was found. The excitation energy of several levels in {sup 24}Al of significance for determination of the {sup 23}Mg(p,{gamma}){sup 24}Al thermonuclear reaction rate were measured. Results are consistent with two of the three previous ({sup 3}He,t) measurements, performed at much lower beam energies. However, a new state at E{sub x}({sup 24}Al)=2.605(10) MeV was found and is the third state above the proton separation energy.

High-energy excited states in 98Cd

In 98Cd a new high-energy isomeric γ-ray transition was identified, which confirms previous spin-parity assignments and enables for the first time the measurement of the E2 and E4 strength for the two decay branches of the isomer. Preliminary results on the 98Cd high-excitation level scheme are presented. A comparison to shell-model calculations as well as implications for the nuclear structure around 100Sn are discussed.

Triaxiality and the determination of the cubic shape parameter K{sub 3} from five observables

The absolute and the relative quadrupole shape invariants

High-resolution study of the Be-9(He-3,t) B-9 reaction up to the B-9 triton threshold

{q}_{3}

Systematic exploration of 0 + states in structurally diverse nuclei

and

High-resolution study of 0+ and 2+ excitations in 168Er with the (p, t) reaction

{K}_{3}

High‐Resolution B(GT) studies with (3He,t)reactions

provide a model independent measure of triaxiality for \ensuremath{\beta}-rigid nuclei. We will show that one can obtain approximate values of

Lo w-Energy Super Gamow-Teller State

{q}_{3}