Speaker
Description
The hydrogen anion H$^-$ is the lightest stable anion and its bound states and resonances are well studied, but magnetic shielding has not been computed to comparable precision. Due to the planned comparison of the bare antiproton to H$^-$ in a Penning trap, we study the magnetic shielding of H$^-$ using nonrelativistic quantum electrodynamics theory (NRQED). We compute the nonrelativistic shielding (of order $\alpha^2$), as well as finite nuclear mass ($\mathcal{O}({m}/{M_n})$), relativistic ($\mathcal{O}(\alpha^4)$), and partial QED ($\mathcal{O}(\alpha^5)$) corrections. We find that the finite nuclear mass correction is the most significant correction to shielding in H$^-$, contributing about $0.1\%$ of the total shielding – more than twice the relativistic correction. Our final result for the shielding constant has a nine-parts-per-trillion accuracy and paves the way for a direct antiproton-to-proton magnetic moment comparison.