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تسجيل مستخدم جديدUniversality of many-body two-nucleon momentum distributions: the correlated nucleon spectral function of complex nuclei revisited
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Realistic NN interactions and many-body approaches have been used to calculate ground-state properties of nuclei with A=3, 4, 12, 16, 40, with particular emphasis on various kinds of momentum distributions. It is shown that at proper values of the relative (rel) and center-of-mass (c.m.) momenta, the two-nucleon momentum distribution n_A^{N_1N_2} (k_{rel}, K_{c.m.}, theta) exhibits the property of factorization, namely n_A^{N_1N_2} (k_{rel}, K_{c.m.}, theta) simeq n_{rel}(k_{rel}) n_(c.m.)( K{c.m.}). The factorization of the momentum distributions , bearing a universal character, results from a general property of realistic nuclear wave functions, namely their factorization at short inter-nucleon separations. The factorization of the two-nucleon momentum distribution allows one to develop the correlated part of the nucleon spectral function P(k,E) in terms of a convolution integral involving the product of the many-body, parameter-free relative and c.m. momentum distributions of a given nucleus. It is shown that: (i) the obtained spectral function perfectly satisfies the momentum sum rule, i.e. when it is integrated over the removal energy E, it fully reproduces the momentum distributions obtained from realistic many-body wave functions , (ii) in order to saturate the momentum sum rule at high values of the momentum (k simeq 5 fm^{-1}) the spectral function has to be integrate up to E simeq 400 MeV. To sum up a realistic, parameter-free many-body Spectral function has been developed such that : i) a phenomenological convolution spectral function developed in the past is fully justified from a many-body point of view , and (ii) the model dependence which might be present in calculations of inclusive electroweak processes could be reduced by the use of the convolution spectral function developed here.
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Talk given at the International Workshop on (e,ep) Processes, July 2-6, 2017, Bled, Slovenia. Various many-body calculations are compared and the results provided by the Normalization Conserving Linked Cluster Expansion with realistic NN interactions
are reviewed and analyzed in detail, as far as ground state energies, momentum distributions and spectral functions of few-nucleon system and complex nuclei are concerned.
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