Proposed detection of variation inmp/meusing a vibrational transition frequency of a CaH+ion

This paper proposes the detection of the variation in the proton-to-electron mass ratio β by measuring a pure vibrational transition frequency of a cold CaH + ion. The uncertainty of the this frequency can potentially be on the order of 10 −16 , because the uncertainties of the Zeeman and Stark shifts are lower than 10 −16 and the electric quadrupole shift is zero. It is practicable to produce a CaH + ion at a certain quantum state and perform sympathetic cooling by using the collisions with a laser-cooled Ca + ion.