Köln 2025 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 54: Fundamental Symmetries II

HK 54.1: Gruppenbericht

Donnerstag, 13. März 2025, 15:45–16:15, SR 0.01 Erw. Physik

Achieving and measuring ultra-low magnetic field gradients for measurements of the 129Xe-EDM- — •Felix Grüner — Physikalisches Institut, Uni Heidelberg

In the Standard Model, the electric dipole moment (EDM) of ¹²⁹Xe arises solely from the CP violation of the weak interaction. Additional sources of CP violation beyond the SM, as needed to explain e.g. baryon asymmetry, should cause a larger xenon EDM. The method used to measure smallest EDMs, comagnetometry, requires exceptionally homogeneous magnetic fields with field gradients of the order of pT/cm. Achieving this requirement necessitates advanced magnetic shielding.

The goal of the Helium-Xenon Experiment is to set a new upper limit on the xenon EDM. For this purpose, a Magnetically Shielded Room (MSR) was constructed at the Physikalisches Institut at Heidelberg University. This talk focuses on how the MSR achieves those low field gradients by active and passive shielding, as well as the determination of magnetic field gradients within the MSR of the order of pT/cm by measuring spin relaxation time constants.

Keywords: electric dipole moment; EDM; diamagnetic atoms; magnetic field gradient; magnetic field shielding