Universality of nucleon-nucleon short-range correlations: two-nucleon momentum distributions in few-body systems

الأصل · EN

Using realistic wave functions, the proton-neutron and proton-proton momentum distributions in ³He and ⁴He are calculated as a function of the relative, krel, and center of mass, KCM, momenta, and the angle between them. For large values of krel 2fm⁻¹ and small values of KCM 1.0fm⁻¹, both distributions are angle independent and decrease with increasing KCM, with the pn distribution factorizing into the deuteron momentum distribution times a rapidly decreasing function of KCM, in agreement with the two-nucleon (2N) short range correlation (SRC) picture. When KCM and krel are both large, the distributions exhibit a strong angle dependence, which is evidence of three-nucleon (3N) SRC. The predicted center-of-mass and angular dependence of 2N and 3N SRC should be observable in two-nucleon knock-out processes A(e,e'pN)X.