20-25 October 2019
Europe/Zurich timezone

The n3He experiment---a new era in Hadronic Parity Violation

22 Oct 2019, 10:10
WHGA/001 - Auditorium (PSI)

WHGA/001 - Auditorium


Oral Session


Christopher Crawford (University of Kentucky)


We report the parity violating proton asymmetry $A_p$ in the reaction $\vec{\mbox{n}}$ + $^{3}$He $\to$ p + $^{3}$H (the n-$^3$He experiment), the most precise hadronic asymmetry ever measured. Hadronic parity violation offers a unique probe of nucleon structure and the underlying non-perturbative behavior of low-energy QCD. The hadronic weak interaction is characterized by five spin and isospin dependent S-P transition amplitudes. While it was first observed over 50 years ago in compound nuclei, which offer large nuclear enhancements, a systematic characterization of the weak interaction among strongly bound systems is still forthcoming, and requires multiple measurements in few-body systems with exactly calculable nuclear wave functions. New theoretical frameworks, experimental facilities, and advanced technology have rejuvenated efforts to map out this "complexity frontier" of the Standard Model. The n-$^3$He experiment is a critical measurement in this campaign, being sensitive to the $\Delta I = 0,1$ transition amplitudes. It was performed at the Fundamental Neutron Physics Beamline at Oak Ridge National Laboratory.

Primary author

Christopher Crawford (University of Kentucky)

Presentation Materials