Inhomogeneous and intrinsic damping of giant dipole resonance in hot rotating nuclei withA∼ 150

Abstract

High-energy gamma rays in the range of ∼4–28 MeV were measured in the reaction 28Si+124Sn at E(28Si) ∼ 185 MeV in coincidence with low-energy gamma ray multiplicities and evaporation residues. The centroid energy and width of the giant dipole resonance were extracted for various multiplicity windows from the statistical model analysis. These extracted widths, along with those from an earlier measurement at E(28Si) ∼ 149 MeV, show a discrepancy with the results of a calculation under the thermal shape fluctuation model which describes the inhomogeneous damping of the resonance. An empirical form of the temperature and angular momentum dependence of the width, describing the data at both the beam energies, has been derived. The present results suggest that the contributions from both the inhomogeneous damping and the intrinsic collisional damping processes should be included.

Spin gated GDR widths at moderate temperatures

“…The experimental widths are consistent with both models. In the case of Kusnezov parametrization, a few authors have reported a change in Γ 0 value at different excitation energies [13], whereas same value of Γ 0 is consistent for 144 Sm at different excitation energies. …”

Exclusive giant dipole resonance measurement on the Jacobi transition in the19F+27Al system

“…The value was ascertained from our earlier measurements with monoenergetic high-energy γ rays produced in the 27 Al(p,γ ) and 11 B(p,γ ) reactions as discussed in Ref. [8]. The gain variation of the detectors was periodically monitored with the radioactive sources and was taken into account in the data analysis by dividing the experimental runs into different groups.…”

“…In this experiment a low-energy component at ∼10. 8 MeV was seen in the GDR strength function in addition to two other components at ∼18 and 26 MeV. The lowest component was interpreted to be due to the vibration along the most elongated axis of the highly deformed nuclei and further shifted downward due to the Coriolis splitting.…”

Examination of level density prescriptions for the interpretation of high-energyγ-ray spectra

“…The giant dipole resonance (GDR), an archetypical example of collective vibrational mode built on excited nuclear states, provides us the insight of exotic nuclear shapes and structure [1][2][3]. Ardent experimental and theoretical interests [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] can be seen over the years in studying the properties of the GDR built on excited states in nuclei as this collective mode is strongly coupled to nuclear damping and shape degrees of freedom. The strength (S GDR ), centroid energy (E GDR ) and width (Γ GDR ) are the parameters that describe a GDR strength function.…”