He at 87 MeV and 100 MeV*

The electromagnetic polarizabilities of the nucleon are fundamental structure constants that describe its response to external electric and magnetic fields. Chiral Effective Field Theory (χEFT) has been used to extract proton polarizabilities from Compton-scattering measurements on hydrogen and neutron polarizabilities from Compton experiments on deuterium. However, neutron polarizabilities have significantly larger uncertainties compared to those of the proton. Further developments in χEFT now allow for a meaningful interpretation of Compton data on low-Z nuclear targets, up to and including ⁴He. The High Intensity Gamma-Ray Source (HIGS) at Duke University delivers a monoenergetic photon beam that provides the external electromagnetic field to low-Z nuclear targets. During the summer of 2025, two experiments were conducted at HIGS to measure Compton-scattering cross sections of ⁴He at eight angles covering 40° – 160° using photon beams of 87 MeV and 100 MeV. In this talk, preliminary results from these experiments will be presented, along with a detailed discussion of the experimental setup and analysis procedures.