Impact of motion along the field direction on geometric-phase-induced false electric dipole moment signals

TL;DR

This paper investigates how particle motion along the magnetic field direction influences false EDM signals caused by geometric phase effects, especially considering wall surface roughness and cell size, using Monte Carlo simulations.

Contribution

It introduces the impact of motion along the field direction on false EDM signals, extending previous transverse-plane analyses with new Monte Carlo results.

Findings

Motion along the field affects false EDM signals depending on cell size.

Diffuse wall collisions significantly influence the magnitude of false signals.

Results highlight the importance of wall surface properties in EDM experiments.

Abstract

Geometric-phase-induced false electric dipole moment (EDM) signals, resulting from interference between magnetic field gradients and particle motion in electric fields, have been studied extensively in the literature, especially for neutron EDM experiments utilizing stored ultracold neutrons and co-magnetometer atoms. Previous studies have considered particle motion in the transverse plane perpendicular to the direction of the applied electric and magnetic fields. We show, via Monte Carlo studies, that motion along the field direction can impact the magnitude of this false EDM signal if the wall surfaces are rough such that the wall collisions can be modeled as diffuse, with the results dependent on the size of the storage cell's dimension along the field direction.