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Description
In the atomic nucleus there exist a strong nucleon-nucleon (NN) interaction at short distance. When a two-nucleon pair are separated by $r_{1,2} \leq 1.5$ fm, they will interact strongly and and the pair obtains large back-to-back relative momenta. The probability of these short distance interactions is enhanced by the tensor force in isospin=0 neutron-proton ($np$) pairs. Under certain kinematic conditions, 4-momentum transfer $Q^2>1.3$ GeV$^2$, Bjorken $x>1.4$, Quasi-elastic electron scattering (QES) isolates those events producing nucleons with high initial momentum allowing the study this isospin dominance.
In 2018, the experiment E12-11-112 at Jefferson Lab measured inclusive electron cross sections of deuterium, tritium, and helium-3 at $0.4 \leq Q^2 \leq 2.2 $GeV$^2$. In the extracted $^3$H/$^2$H ($^3$He/$^2$H) cross section ratios, we observed plateaus in the region of the NN short-range correlation (NN-SRC) dominant kinematics. The predicted scaling behavior of NN-SRC pairs in A=3 nuclei and in the deuteron is confirmed as is the isospin dominance of NN-SRC pairs. By comparing the mirror nuclei of $^3$H and $^3$He, we extracted the relative of of $np$ to $pp$($nn$) SRC pairs in the A=3 system.
