Giant monopole resonances in the statistical model

The strength functions fore ⁺ e ^– pair decay of the isoscalar and isovector giant monopole resonances in highly excited nuclei are derived and used in a statistical model calculation of thee ⁺ e ^– pair energy spectrum from compound nuclear decay in¹¹⁰Sn following a fusion evaporation reaction. This result is then compared to thee ⁺ e ^– spectrum derived from internal pair decay of the giant dipole and giant quadrupole resonances. The computation shows that the pair decay from the excited-state GDR dominates the pair spectrum over the region of all giant resonances, exceedingL=0 transitions by at least a factor of ten. We also compute the angular correlations betweene ⁺ ande ^– for theL=0, L=1 andL=2 transitions and estimate their power to discriminate between the various multipolarities.Dedicated to Prof. Dr. P. Kienle on the occasion of his 60th birthday