Speaker
Description
Hyperfine structure measurements on antihydrogen can provide sensitive tests of CPT invariance. The ASACUSA collaboration proposed such experiments on a beam of antihydrogen at the antiproton decelerator of CERN. We benchmark spectroscopy methods and equipment in supporting matter experiments. Beyond the relevance for antihydrogen these measurements can put new as well as improved constraints on specific coefficients of the so-called standard model extension (SME). Thereby CPT and Lorentz invariance are tested even without comparison to antihydrogen. We have constructed an atomic beam setup for Rabi spectroscopy and performed such measurements on hydrogen at CERN and on deuterium at the Laboratoire Aimé Cotton, Université Paris-Saclay. We obtain constraints, e.g., on the SME non-relativistic (NR) anisotropic proton coefficients $\mathcal{T}^\text{NR, Sun}_{p_{010}}$ by hydrogen and at higher fermion momentum power ($k=2,4$) on $\mathcal{T}^\text{NR, Sun}_{p_{k11}}$ by deuterium, both on the order of $10-20~\text{GeV}$. Determinations of the zero-field hyperfine splitting give agreement with literature (i.e. maser measurements) and the achieved levels of precision around $1~\text{Hz}$ for both atoms present the best values obtained by in-beam spectroscopy in each case.