Probing the isospin mixing in the 72Kr compound nucleus via GDR γdecay

AbstraktAbstract

The isospin mixing was deduced in the compound nucleus 72Kr at a low nuclear temperature around 1.3 MeV, from the gamma decay of the giant dipole resonance. The gamma rays from two compound-nucleus reactions were measured: from the 32 S + 40Ca at bombarding energy of 90 MeV characterized by isospin I = 0, and from the 31 P + 40Ca at 82 MeV used as a reference. The ELIFANT array was employed at the Bucharest Tandem Laboratory, consisting of Compton-suppressed scintillator detectors. The statistical-model analysis of the measured spectra provided a mixing parameter of (3.5 +/- 0.8)%. This new point, being at the lowest temperature compared with the few other existing ones, can validate the predictions of the temperature dependence of the isospin mixing. The isospinsymmetry-breaking correction, delta c, used for the Fermi super-allowed transitions was extracted from the present result of the isospin mixing and found to be consistent with beta decay data, theoretical predictions, and previous experimental results.

The isospin mixing was deduced in the compound nucleus 72Kr at a low nuclear temperature around 1.3 MeV, from the gamma decay of the giant dipole resonance. The gamma rays from two compound-nucleus reactions were measured: from the 32 S + 40Ca at bombarding energy of 90 MeV characterized by isospin I = 0, and from the 31 P + 40Ca at 82 MeV used as a reference. The ELIFANT array was employed at the Bucharest Tandem Laboratory, consisting of Compton-suppressed scintillator detectors. The statistical-model analysis of the measured spectra provided a mixing parameter of (3.5 +/- 0.8)%. This new point, being at the lowest temperature compared with the few other existing ones, can validate the predictions of the temperature dependence of the isospin mixing. The isospinsymmetry-breaking correction, delta c, used for the Fermi super-allowed transitions was extracted from the present result of the isospin mixing and found to be consistent with beta decay data, theoretical predictions, and previous experimental results.