Schiavilla R, Wiringa R B, Pieper Steven C, Carlson J
Jefferson Laboratory, Newport News, VA 23606, USA.
Phys Rev Lett. 2007 Mar 30;98(13):132501. doi: 10.1103/PhysRevLett.98.132501. Epub 2007 Mar 27.
Two-nucleon momentum distributions are calculated for the ground states of nuclei with mass number A< or =8, using variational Monte Carlo wave functions derived from a realistic Hamiltonian with two- and three-nucleon potentials. The momentum distribution of np pairs is found to be much larger than that of pp pairs for values of the relative momentum in the range (300-600) MeV/c and vanishing total momentum. This order of magnitude difference is seen in all nuclei considered and has a universal character originating from the tensor components present in any realistic nucleon-nucleon potential. The correlations induced by the tensor force strongly influence the structure of np pairs, which are predominantly in deuteronlike states, while they are ineffective for pp pairs, which are mostly in 1S0 states. These features should be easily observable in two-nucleon knockout processes, such as A(e,e'np) and A(e,e'pp).
利用从具有两体和三体核子势的现实哈密顿量导出的变分蒙特卡罗波函数，计算了质量数(A\leq8)的原子核基态的两体核子动量分布。发现在相对动量范围为((300 - 600))MeV/c且总动量为零的情况下，中子 - 质子对的动量分布比质子 - 质子对的动量分布大得多。在所考虑的所有原子核中都能看到这种数量级的差异，并且它具有源于任何现实核子 - 核子势中存在的张量分量的普遍特征。由张量力引起的关联强烈影响中子 - 质子对的结构，中子 - 质子对主要处于类氘核态，而它们对主要处于(1S0)态的质子 - 质子对无效。这些特征在两体敲出过程中应该很容易观察到，例如(A(e,e'np))和(A(e,e'pp))。
