Speaker
Description
Given current discrepancy in muon $g-2$ and future dedicated efforts to measure muon electric dipole moment (EDM) $d_\mu$, we assess the indirect constraints imposed on $d_\mu$ by the EDM measurements performed with heavy atoms and molecules. We notice that the dominant muon EDM effect arises via the muon-loop induced “light-by-light” CP-odd amplitude $\propto E^3B$, and in the vicinity of a large nucleus the corresponding parameter of expansion can be significant, $eE_\mathrm{nucl}/m_\mu^2∼0.04$. We compute the $d_\mu$-induced Schiff moment of the $^{199}$Hg nucleus, and the linear combination of $d_e$ and semileptonic $C_S$ operator (dominant in this case) that determine the CP-odd effects in the ThO molecule. The results, $d_\mu ({}^{199}\mathrm{Hg})<6\times 10^{-20}e\,\mathrm{cm}$ and $d_\mu (\mathrm{ThO})<2\times 10^{-20}e\,\mathrm{cm}$, constitute approximately threefold and ninefold improvements over the limits on $d_\mu$ extracted from the Brookhaven National Laboratory muon beam experiment.
