Revealing the short-range structure of the "mirror nuclei" ${}^3$H and ${}^3$He

Abstract

When protons and neutrons (nucleons) are bound into atomic nuclei, they are close enough together to feel significant attraction, or repulsion, from the strong, short-distance part of the nucleon-nucleon interaction. These strong interactions lead to hard collisions between nucleons, generating pairs of highly-energetic nucleons referred to as short-range correlations (SRCs). SRCs are an important but relatively poorly understood part of nuclear structure and mapping out the strength and isospin structure (neutron-proton vs proton-proton pairs) of these virtual excitations is thus critical input for modeling a range of nuclear, particle, and astrophysics measurements. Hitherto measurements used two-nucleon knockout or ``triple-coincidence'' reactions to measure the relative contribution of np- and pp-SRCs by knocking out a proton from the SRC and detecting its partner nucleon (proton or neutron). These measurementsshow that SRCs are almost exclusively np pairs, but had limited statistics and required large model-dependent final-state interaction (FSI) corrections. We report on the first measurement using inclusive scattering from the mirror nuclei ${}^3$H and ${}^3$He to extract the np/pp ratio of SRCs in the A=3 system. We obtain a measure of the np/pp SRC ratio that is an order of magnitude more precise than previous experiments, and find a dramatic deviation from the near-total np dominance observed in heavy nuclei. This result implies an unexpected structure in the high-momentum wavefunction for ${}^3$He and ${}^3$H. Understanding these results will improve our understanding of the short-range part of the N-N interaction.

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• Effects of the $\alpha$-cluster structure and the intrinsic momentum component of nuclei on the longitudinal asymmetry in relativistic heavy-ion collisions
• Short-range correlations and momentum distributions in mirror nuclei 3H and 3He
• Nucleon Short-Range Correlations and High-Momentum Dynamics: Implications on the Equation of State of Dense Matter
• Nuclear three-body short-range correlations in coordinate space
• Observing short-range correlations in nuclei through ${\rho }^0$ photo-production
• Physical Implications of the Extrapolation and Statistical Bootstrap of the Nucleon Structure Function Ratio $\frac{F_2^n}{F_2^p}$ for Mirror Nuclei ${}^3$He and ${}^3$H
• Tri-meson state $\bar{\mathbf{B}}{\bar{\mathbf{B}}}^{\ast }{\bar{\mathbf{B}}}^{\ast }$
• Predicted Measurements of the Tensor-to-Scalar Transition in the CLAS12 Nuclear Targets Experiment
• A novel measurement of the neutron magnetic form factor from A=3 mirror nuclei
• Nucleon momentum distributions of complex nuclei from inclusive electron scattering
• Neutron Star Equation of State with Nucleon Short-Range Correlations: A Concise Review and Open Issues