The nuclear single-particle spectral function is considered in the region of high momentum and high removal energy. For these kinematical conditions, far away from the quasi-particle peak, the spectral function is expected to be dominated by nucleon-nucleon correlations. It has been previously argued that the spectral function can be written as a convolution between the two-body relative momentum distribution and the corresponding centre-of-mass distribution of the correlated pairs which characterize the structure of the ground state in this energy-momentum region. It is shown that the convolution model can be microscopically derived from the Brueckner-Bethe-Goldstone (BBG) expansion. At the same time, this result also allows us to establish a direct link between the spectral function and the defect function of the BBG theory. From a numerical comparison with the microscopic spectral function the convolution model turns out to be highly accurate in the relevant momentum and energy range
The high momentum and energy behaviour of the nucleon spectral function of nuclear matter within the Brueckner-Bethe-Goldstone approach
BORROMEO, Marcello;CIOFI DEGLI ATTI, Claudio
1996
Abstract
The nuclear single-particle spectral function is considered in the region of high momentum and high removal energy. For these kinematical conditions, far away from the quasi-particle peak, the spectral function is expected to be dominated by nucleon-nucleon correlations. It has been previously argued that the spectral function can be written as a convolution between the two-body relative momentum distribution and the corresponding centre-of-mass distribution of the correlated pairs which characterize the structure of the ground state in this energy-momentum region. It is shown that the convolution model can be microscopically derived from the Brueckner-Bethe-Goldstone (BBG) expansion. At the same time, this result also allows us to establish a direct link between the spectral function and the defect function of the BBG theory. From a numerical comparison with the microscopic spectral function the convolution model turns out to be highly accurate in the relevant momentum and energy rangeI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.