Speaker
Dr
Adam Holley
(Indiana University)
Description
The current experimental upper limit on the parity violating neutron spin rotation angle in liquid $^4$He, $\phi_\mathrm{PV}$, is $10^{-6}$~rad/m, consistent with the current theoretical expectation of $10^{-7}$ to $10^{-6}$~rad/m. With the parity violating hadronic weak interaction experiment NPDGamma close to completion, plans for a n$^3$He experiment complementary to neutron spin rotation underway, and in light of advances in quantum chromodynamic computations on the lattice, obtaining a value for $\phi_\mathrm{PV}$ is an increasingly important goal. The neutron spin rotation collaboration is mounting an experiment to provide such a measurement. This new experiment is based on the previous effort which provided the current limit on $\phi_\mathrm{PV}$, but leverages the flux available on the new NG-C fundamental physics beamline at the National Institute of Standards and Technology (NIST) Center for Neutron Research, new cryogenics technology and techniques, and enhanced magnetic shielding to improve the sensitivity to $\phi_\mathrm{PV}$ by an order of magnitude. The current theoretical and experimental status of $\phi_\mathrm{PV}$ will be reviewed in light of other hadronic weak interaction measurements, and the design of our new spin rotation apparatus will be discussed in relation to its application in placing constraints on the existence of short-range spin dependent fifth forces as well as in a measurement of $\phi_\mathrm{PV}$.
Primary author
Dr
Adam Holley
(Indiana University)
