Recent Results from He6-CRES Towards a Percent Level Measurement of b_fierz

The He6-CRES experiment at the University of Washington CENPA aims to precisely measure the Fierz coefficient b_fierz which parameterizes exotic (non-vector or axial vector) currents in the weak interaction representing a violation of Standard Model physics. The measurement is being done with Cyclotron Radiation Emission Spectroscopy (CRES) - a modern technique for high-precision beta spectroscopy in which the energy of an e^± in an external magnetic field is measured via the frequency of the emitted cyclotron radiation (f_c). A measurement of b_fierz with a 10^-3 uncertainty would be competitive with current LHC searches for tensor currents.

This talk will discuss our most recent results towards a 10^-2 demonstration over 2.4 MeV using both the decays of ⁶He and ¹⁹Ne.