VIRTUAL

Thursday, April 22nd    2021

3:45 – 4:45 p.m.

WEBEX

Speaker:  Prof. Christopher Crawford


Director of Graduate Studies Department of Physics and Astronomy,

University of Kentucky

 

“A New Era in Hadronic Parity Violation”


Abstract: 

Hadronic parity violation is a sensitive probe of the weak force in nuclear interactions,   despite dominance of the strong force by seven orders of magnitude.
This precision frontier of the Standard Model offers a unique perspective of nuclear structure and the underlying non-perturbative behavior of low-energy QCD in the nucleon.
Multiple observables in few-body systems, which have exactly calculable nuclear wave functions, are needed to characterize the spin and isospin dependence of the Hadronic Weak Interaction (HWI).
New effective field theoretical frameworks, experimental facilities, and advanced technology have rejuvenated efforts to map out HWI.
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.
This and the NPDGamma experiment, constrain two combinations of the HWI couplings.
We also describe the new NDTGamma experiment, which will be the first counting mode PV measurement in a few-body system.


Bio:
After completing his PhD at MIT measuring the nucleon form factors (BLAST experiment), Chris did a post-doc at LANL on the NPDGamma experiment.  At the University of Kentucky, he received a DOE CAREER award for techniques in the design of precision electromagnetic coils for the nEDM@SNS experiment.  He has also developed new digital signal processing algorithms for the Nab neutron decay correlation experiment, and new detector configurations for the BL3 neutron lifetime experiment.  His interest in hadronic symmetries continues through the NDTGamma and NOPTREX (time reversal symmetry violation) experiments.