Precision Measurement of the Neutron Scattering Length of ^{4}He Using Neutron Interferometry

Area of Science:

• Nuclear Physics
• Atomic Physics
• Quantum Mechanics

Background:

• The neutron scattering length of Helium-4 (⁴He) is crucial for understanding nuclear interactions and atomic properties.
• Previous measurements have shown discrepancies, necessitating more precise determinations.

Purpose of the Study:

• To achieve a high-precision measurement of the bound neutron scattering length of ⁴He.
• To refine the world average value and reduce its uncertainty.

Main Methods:

• Utilized advanced neutron interferometry techniques.
• Performed precise measurements of neutron scattering in ⁴He.

Main Results:

• Determined the bound neutron scattering length b=(3.0982±0.0021[stat]±0.0014[syst]) fm.
• Calculated the free atomic scattering length a=(2.4746±0.0017[stat]±0.0011[syst]) fm.
• The new world average for b is (3.0993±0.0025) fm, a 2% downward shift with significantly reduced uncertainty.

Conclusions:

• The high-precision measurement provides a refined value for the neutron scattering length of ⁴He.
• The results align with some previous measurements but differ from other interferometric studies.
• This work contributes to a more accurate understanding of fundamental nuclear and atomic physics.