Factorization of exclusive electron-induced two-nucleon knockout

Abstract

We investigate the factorization properties of the exclusive electroinduced two-nucleon knockout reaction A(e,e pN). A factorized expression for the cross section is derived and the conditions for factorization are studied. The A(e,e pN) cross section is shown to be proportional to the conditional center-of-mass (c.m.) momentum distribution for close-proximity pairs in a state with zero relative orbital momentum and zero radial quantum number. The width of this conditional c.m. momentum distribution is larger than the one corresponding with the full c.m. momentum distribution. It is shown that the final-state interactions (FSIs) only moderately affect the shape of the factorization function for the A(e,e pN) cross sections. Another prediction of the proposed factorization is that the mass dependence of the A(e,e pp) [A(e,e pn)] cross sections is much softer than[NZ].

Production of pentaquarks inpA-collisions

“…This object has been extensively studied in various theoretical models of nuclear structure [51][52][53][54][55], yielding similar results. For infinite nuclear matter, as well as inside a finite nuclei far from a nuclear border, C ( x 1 , x 2 ) depends only on the distance between the two nucleons,…”

Final-state interactions in two-nucleon knockout reactions

“…Indeed, above the Fermi momentum, the k 12 distribution of the pairs is strongly decreasing with increasing | k 12 | [22,23]. This makes it highly unlikely that the fast nucleon in the final state is not the one that absorbed the virtual photon.…”

“…The proposed factorization of the cross section in terms of F pp,D A was first confirmed in 12 C(e, e pp) measurements back in the late 1990s [9]. An effort is on its way to extract the width of the F pp,D A distribution in A(e, e pp) measurements on 12 C, 27 Al, 56 Fe and 208 Pb [25,26], and compare them with the theoretical predictions [22]. Another striking prediction of the expression (3) is that the A(e, e pN ) cross section is proportional to the number of close-proximity pN pairs in the target nucleus.…”

“…II, we discuss the approximations underlying the factorized form of the A(e, e pN ) cross section (detailed in Ref. [22]) and how we implement the FSI. Using the factorized A(e, e pN ) cross-section expression, we show in Sec.…”

“…[22,24], in kinematics probing SRC pairs, it is possible to factorize the A(e, e pN ) cross section in a product of a function depending on the relative momentum k 12 , and a part depending on the c.m. momentum…”