Overlap functions in correlation methods and quasifree nucleon knockout from16O

Abstract

The cross sections of the (e, e ′ N ) and (γ, p) reactions on

Effects of short-range correlations in(e,e′p)reactions and nuclear overlap functions

“…This was confirmed in an exactly solvable many-body system in one dimension with a zerorange interaction [18]. The theorem was applied in [19] to obtain the overlap functions and spectroscopic factors from a model OBDM including Jastrow correlations, and later [20,21] applied to the calculation of cross sections for several reactions, such as (p, d), (e, e ′ p) and (γ, p). However, some problems with the numerical restoration procedure performed in [19], which is based on an exponential fit of the OBDM, were pointed out in [15], namely: i) the use of harmonic-oscillator single-particle wave functions, which do not have the correct exponential behavior in the asymptotic region, to construct the OBDM, and ii) the nature of the exponential fit allowed to obtain in [19] overlap functions for the unoccupied states, while in [15] it was demonstrated that such extraction is not possible starting from a CBF-type wave function.…”

“…Recently Gaidorov et al [21] have presented results for the overlap functions of the p-shell in 16 O using a method similar to fit II. The procedure was applied to the correlated OBDM of [32] computed up to 11 fm, which uses the same shell model we are considering here, with similar energies and wave functions for the 1p 1/2 and 1p 3/2 .…”

“…In particular, the one obtained in [22] by a truncated cluster expansion of the radial multipoles ρ l (r, r ′ ) of the OBDM. Using the above density, spectroscopic factors corresponding to the p 1/2 and p 3/2 shells of 16 O were reported [21] to be identical in this model and equal to 0.981. The equality of these values is probably due to the fact that the restoration procedure in [21] started from a OBDM for l = 1 which (i) was not separated in spin partners j = 1/2, 3/2, and that (ii) was computed up to distances of r, r ′ = 11 fm, which are not large enough to separate asymptotically the two contributions p 1/2 and p 3/2 .…”

“…Using the above density, spectroscopic factors corresponding to the p 1/2 and p 3/2 shells of 16 O were reported [21] to be identical in this model and equal to 0.981. The equality of these values is probably due to the fact that the restoration procedure in [21] started from a OBDM for l = 1 which (i) was not separated in spin partners j = 1/2, 3/2, and that (ii) was computed up to distances of r, r ′ = 11 fm, which are not large enough to separate asymptotically the two contributions p 1/2 and p 3/2 . This fact, together with the problems pointed out above, makes possible that some of the effects attributed in [21] to short-range correlations, actually be a consequence of the extraction procedure of the overlap functions.…”

“…In reference [21] the same restoration procedure was applied to compute overlap functions using several correlated OBDM taken from the literature. In particular, the one obtained in [22] by a truncated cluster expansion of the radial multipoles ρ l (r, r ′ ) of the OBDM.…”