Order of Magnitude Smaller Limit on the Electric Dipole Moment of the Electron

Abstract

The Standard Model of particle physics is known to be incomplete. Extensions to the Standard Model, such as weak-scale supersymmetry, posit the existence of new particles and interactions that are asymmetric under time reversal (T) and nearly always predict a small yet potentially measurable electron electric dipole moment (EDM), d(e), in the range of 10(-27) to 10(-30) e·cm. The EDM is an asymmetric charge distribution along the electron spin (S(→)) that is also asymmetric under T. Using the polar molecule thorium monoxide, we measured d(e) = (-2.1 ± 3.7stat ± 2.5syst) × 10(-29) e·cm. This corresponds to an upper limit of |d(e)| < 8.7 × 10(-29) e·cm with 90% confidence, an order of magnitude improvement in sensitivity relative to the previous best limit. Our result constrains T-violating physics at the TeV energy scale.

Enhancement ofBr(Bd→μ+μ−Dutta1, Mimura2 2015Phys. Rev. D6060View full textAdd to dashboardCite

“…The electron EDM can also be enhanced by a neutralino diagram (for Bino components), if FCNC contributions arise from both leftand right-handed charged-slepton mass matrices induced by (3, 2, − 7 6 )+c.c. couplings, and it can be comparable to the current experimental bound |d e | < 8.7 × 10 −29 e · cm [19].…”

Direct and indirect constraints on CP-violating Higgs-quark and Higgs-gluon interactions

“…At the moment, the strongest constraints have been set on the EDMs of the neutron [46], d n , the 199 Hg atom [47], d Hg , the 129 Xe atom [49], d Xe , and on the energy shift indicating T violation in the ThO molecule [48]. As discussed below, for our purposes the latter can be interpreted as a constraint on the EDM of the electron, d e .…”

“…The strongest constraints arise from measurements on the neutron [46], the 199 Hg atom [47], and the ThO molecule [48]. To interpret the experimental upper bounds, it is necessary to express the observables in terms of the Wilson coefficients of the dimension-6 operators and the corresponding hadronic and nuclear matrix elements.…”

“…For the operator set discussed in this paper, there appear no significant contributions to CPV electron-quark interactions, 10 such that paramagnetic EDMs are dominated by d e . The strongest constraint then arises from the ThO measurement which gives [48] d e ≤ 8.7 · 10 −29 e cm , (3.6)…”

Forbidden Vibrational Transitions in Cold Molecular Ions: Experimental Observation and Potential Applications

“…The natural linewidth is estimated to be several orders of magnitude smaller (approximately nanohertz [1] ) and the Doppler width at the temperature of the ions amounts to approximately 1. as a possible variation of fundamental physical constants, [16] the existence of yet unknown fundamental interactions [17] or to constrain the magnitude of the electron's electric dipole moment. [18] Many of these questions can suitably be studied with the rotation-vibration spectra of molecules. Molecular rotation-vibration transitions show, e.g., a more prominent dependence on a possible variation of the proton to electron mass ratio m p /m e than atomic term energies [19] and they also provide a way to search for unknown long-range hadron-hadron interactions.…”