Date Available


Year of Publication


Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation


Arts and Sciences


Physics and Astronomy

First Advisor

Dr. Bradley Plaster


We study the combined sensitivity of measurements of electron-proton coincidence asymmetries in polarized neutron beta-decay together with a measurement of the electron energy spectrum in unpolarized neutron beta-decay to beyond Standard Model (BSM) scalar and tensor interactions, via the appearance of such BSM physics in the Fierz interference terms b and bv. Whereas measurements of the electron energy spectrum directly probe b, both the proton and neutrino asymmetries for which experimental results exist are not sensitive to bv, but effectively to b - bv. This results in reduced sensitivity to BSM scalar and tensor physics as the dependencies of bv and b on scalar and tensor physics are similar. As a remedy, we demonstrate that ratios of certain asymmetries are sensitive only to bv, thus providing a new paradigm for directly accessing bv. We find that with 1X109 events, a combined fit to our asymmetry ratios and the spectrum yields sensitivity to b and bv at the level of ~ 2 x 10-3.

Digital Object Identifier (DOI)

Funding Information

This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Award Number DE-SC0014622, 2017-2020.