New Observables for Parity Violation in Atoms: Energy Shifts in External Electric Fields

Abstract

We consider hydrogen-like atoms in unstable levels of principal quantum number n=2, confined to a finite size region in a non-homogeneous electric field carrying handedness. The interplay between the internal degrees of freedom of the atoms and the external ones of their c.m. motion can produce P-odd contributions to the eigenenergies. The nominal order of such shifts is 10^-8 Hz. Typically such energy shifts depend linearly on the small P-violation parameters delta_i similarequal 10^-12 (i=1,2), essentially the ratios of the P-violating mixing matrix elements of the 2S and 2P states over the Lamb shift, with i=1 (i=2) corresponding to the nuclear spin independent (dependent) term. We show how such energy shifts can be enhanced by a factor of similarequal 10^6 in a resonance like way for special field configurations where a crossing of unstable levels occurs, leading to P-violating effects proportional to squareroot{delta_i}. Measurements of such effects can give information concerning the ``spin crisis'' of the nucleons.