Precision Measurement of the n-3He Incoherent Scattering Length Using Neutron Interferometry

Abstract

We report the first measurement of the low-energy neutron-${}^3$He incoherent scattering length using neutron interferometry: $b_i^{\prime }=(-2.512\pm 0.012statistical\pm 0.014systematic)$ fm. This is in good agreement with a recent calculation using the AV18+3N potential. The neutron-${}^3$He scattering lengths are important for testing and developing nuclear potential models that include three nucleon forces, effective field theories for few-body nuclear systems, and neutron scattering measurements of quantum excitations in liquid helium. This work demonstrates the first use of a polarized nuclear target in a neutron interferometer.

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