Abstract
The ratio of - to -shell electron captures in light nuclei is particularly sensitive to electron overlap and exchange effects. Calculations of these effects in disagree by more than . We report a measurement of the ratio in , using a cryogenic microcalorimeter which clearly separates - and -shell captures. The obtained ratio of 0.040(6) is less than half that of existing predictions for free . The discrepancy is likely due to in-medium effects distorting the -shell electron orbitals.
- Received 24 May 2001
DOI:https://doi.org/10.1103/PhysRevLett.88.012501
©2001 American Physical Society