Diffractive dissociation of alpha particles as a test of isophobic short-range correlations inside nuclei
Abstract
The CLAS collaboration at Jefferson Laboratory has compared nuclear parton distributions for a range of nuclear targets and found that the EMC effect measured in deep inelastic lepton-nucleus scattering has a strongly “isophobic” nature. This surprising observation suggests short-range correlations between neighboring n and p nucleons in nuclear wavefunctions that are much stronger compared to p−p or n−n correlations. In this paper we propose a definitive experimental test of the nucleon-nucleon explanation of the isophobic nature of the EMC effect: the diffractive dissociation on a nuclear target A of high energy He4 nuclei to pairs of nucleons n and p with high relative transverse momentum, α+A→n+p+A′+X. The comparison of n−p events with p−p and n−n events directly tests the postulated breaking of isospin symmetry. The experiment also tests alternative QCD-level explanations for the isophobic EMC effect. In particular it will test a proposal for hidden-color degrees of freedom in nuclear wavefunctions based on isospin-zero [ud] diquarks.