Magnetic field uniformity in neutron electric dipole moment experiments

Abstract

Magnetic field uniformity is of the utmost importance in experiments to measure the electric dipole moment of the neutron. A general parametrization of the magnetic field in terms of harmonic polynomial modes is proposed, going beyond the linear-gradients approximation. We review the main undesirable effects of non-uniformities: depolarization of ultracold neutrons, and Larmor frequency shifts of neutrons and mercury atoms. The theoretical predictions for these effects were verified by dedicated measurements with the single-chamber nEDM apparatus installed at the Paul Scherrer Institute.

References in corpus (34)

• Electric dipole moments as probes of new physics
• Electric Dipole Moments of Nucleons, Nuclei, and Atoms: The Standard Model and Beyond
• A Revised Experimental Upper Limit on the Electric Dipole Moment of the Neutron
• Electric Dipole Moments of the Atoms, Molecules, Nuclei and Particles
• Reduced Limit on the Permanent Electric Dipole Moment of ${}^{199}$Hg
• The neutron and its role in cosmology and particle physics
• Probing exotic phenomena at the interface of nuclear and particle physics with the electric dipole moments of diamagnetic atoms: A unique window to hadronic and semi-leptonic CP violation
• Detailed Discussion of a linear electric field frequency shift induced in confined gases by a magnetic field gradient: Implications for neutron electric dipole moment experiments
• Plans for a Neutron EDM Experiment at SNS
• Apparatus for Measurement of the Electric Dipole Moment of the Neutron using a Cohabiting Atomic-Mercury Magnetometer
• Comparison of ultracold neutron sources for fundamental physics measurements
• Linear electric field frequency shift (important for next generation electric dipole moment searches) induced in confined gases by a magnetic field gradient
• Probing Dark Energy models with neutrons
• A measurement of the neutron to 199Hg magnetic moment ratio
• Electric dipole moment searches: reexamination of frequency shifts for particles in traps
• Observation of gravitationally induced vertical striation of polarized ultracold neutrons by spin-echo spectroscopy
• Measurement of a false electric dipole moment signal from ${}^{199}$Hg atoms exposed to an inhomogeneous magnetic field
• Frequency shifts and relaxation rates for spin 1/2 particles moving in electromagnetic fields
• Relaxation of spins due to a magnetic field gradient, revisited; Identity of the Redfield and Torrey theories
• Ultracold neutron detection with 6Li-doped glass scintillators, NANOSC: a fast ultracold neutron detector for the nEDM experiment at the Paul Scherrer Institute
• Dipole-Field Contributions to Geometric-Phase-Induced False Electric-Dipole Moment Signals for Particles in Traps
• Comment on "An Improved Experimental Limit on the Electric-Dipole Moment of the Neutron," C.A.Baker et al [hep-ex/0602020]
• Gravitational Depolarization of Ultracold Neutrons: Comparison with Data
• Spin relaxation and linear-in-electric-field frequency shift in an arbitrary, time-independent magnetic field
• Gravitationally enhanced depolarization of ultracold neutrons in magnetic field gradients, and implications for neutron electric dipole moment measurements
• Demonstration of sensitivity increase in mercury free-spin-precession magnetometers due to laser-based readout for neutron electric dipole moment searches
• Random walks with thermalizing collisions in bounded regions; physical applications valid from the ballistic to diffusive regimes
• Geometric phases in electric dipole searches with trapped spin-1/2 particles in general fields and measurement cells of arbitrary shape with smooth or rough walls
• Geometric phases in electric dipole searches with spin-1/2 particles from spin dependent Schrödinger equation
• Calculation of geometric phases in electric dipole searches with trapped spin-1/2 particles based on direct solution of the Schrödinger equation
• How the minuscule can contribute to the big picture: the neutron electric dipole moment project at TRIUMF
• The quest for an electric dipole moment of the neutron
• Magnetic Field Devices for Neutron Spin Transport and Manipulation in Precise Neutron Spin Rotation Mesurements
• Worldwide Search for the Neutron EDM

Cited by in corpus (19)

• Measurement of the permanent electric dipole moment of the neutron
• A New Cryogenic Apparatus to Search for the Neutron Electric Dipole Moment
• The design of the n2EDM experiment
• The `n2EDM MSR' -- a very large magnetically shielded room with an exceptional performance for fundamental physics measurements
• Optically Pumped Cs Magnetometers Enabling a High-Sensitivity Search for the Neutron Electric Dipole Moment
• The n2EDM experiment at the Paul Scherrer Institute
• The PanEDM Neutron Electric Dipole Moment Experiment at the ILL
• Bespoke magnetic field design for a magnetically shielded cold atom interferometer
• nEDM experiment at PSI: data-taking strategy and sensitivity of the dataset
• Mapping of the magnetic field to correct systematic effects in a neutron electric dipole moment experiment
• Search for electric dipole moments
• A search for neutron to mirror neutron oscillation using neutron electric dipole moment measurements
• The physical meaning of the magnetic scalar potential, and how to use it to design an electromagnet
• Search for an interaction mediated by axion-like particles with ultracold neutrons at the PSI
• A Three-step Model for Optimizing Coil Spacings Inside Cuboid-shaped Magnetic Shields
• Johnson-Nyquist Noise Effects in Neutron Electric-Dipole-Moment Experiments
• A novel technique of extracting UCN lifetimes from storage bottle measurements dominated by scattering losses
• Ultracold Neutron Storage Simulation Using the Kassiopeia Software Package
• Wigner-Eckart Theorem and the False EDM of ${}^{199}$Hg