Conveners
Fundamental Symmetry Tests
- Leah Broussard (Oak Ridge National Laboratory)
Fundamental Symmetry Tests
- Leah Broussard (Oak Ridge National Laboratory)
The Electric Dipole Moment (EDM) of elementary particles, including hadrons, is considered as one of the most powerful tools to study CP-violation beyond the Standard Model. Such CP-violating mechanisms are searched for to explain the dominance of matter over anti-matter in our universe.
Up to now EDM experiments concentrated on neutral systems, namely neutron, atoms and molecules. Storage...
A new method has been demonstrated using the storage ring COSY to search for an axion-like particle by scanning for a resonance in the horizontal-plane rotation of the deuteron beam polarization. If an electric dipole moment (EDM) is present on the nucleus, the radial electric field that exists in the particle frame will create a rotation of the polarization out of the horizontal plane and...
Axions are CP-odd scalar particles appearing in many extensions of the Standard Model. In particular, the Peccei-Quinn axion can explain the smallness of the neutron electric dipole moment and is also a promising Dark Matter candidate. Axions also generate macroscopic P-odd and T-odd spin-dependent interactions which can be sought in sensitive laboratory experiments. As the axion's coupling to...
Macroscopic forces of nature beyond gravity and electromagnetism arise in many frameworks attempting to unify General Relativity and the Standard Model. We describe an experimental search for spin-dependent fifth forces in the sub-millimeter range. The experiment uses planar mechanical oscillators as test masses, which have been augmented with polarized rare earth iron garnets. These...
Critical dressing, the simultaneous dressing of two spin species to the same effective Larmor frequency, is a technique that can, in principle, improve the sensitivity to small frequency shifts. The benefits of spin dressing and thus critical dressing are achieved at the expense of generating a large (relative to the holding field $B_{0}$,) homogeneous oscillating field. Due to inevitable...
The existence and size of a neutron electric dipole moment (nEDM) remains an important question in particle and cosmological physics. The SNS nEDM experiment proposes a new limit for nEDM search by using ultra-cold neutrons (UCN) in a bath of superfluid helium. The experiment uses polarized 8.9Å neutrons to create polarized UCN in situ in superfluid helium via superthermal downscattering. This...
The Nab experiment at the Fundamental Neutron Physics Beamline (FnPB) at the Spallation Neutron Source (SNS) aims to make precision measurements of the electron-neutrino correlation and Fierz interference term, associated with the beta decay of free neutrons. Residual polarization of the incident beam presents a potential source of systematic error in this measurement. In order to understand...
The Neutron Spin Rotation (NSR) slow neutron polarimeter is an apparatus designed to measure and constrain fundamental interactions to high precision through the use of neutron optical techniques. This apparatus was initially constructed to search for parity-violating spin rotation of neutrons transmitted through liquid $^{4}\text{He}$. This experiment placed a limit on the rotation angle per...
