Laser-coolable AcOH+ ion for CP-violation searches

The AcOH+ molecular ion is identified as a prospective system to search for CP-violation effects. According to our study AcOH+ belongs to the class of laser-coolable polyatomic molecular cations implying a large coherence time in the experiments to study symmetry-violating effects of fundamental interactions. We perform both nuclear and high-level relativistic coupled cluster electronic structure calculations to express the experimen-tally measurable T, P-violating energy shift in terms of fundamental quantities such as the nuclear magnetic quadrupole moment (MQM), electron electric dipole moment (eEDM) and dimensionless scalar-pseudoscalar nuclear-electron interaction constant. We further express nuclear MQM in terms of the strength constants of CP-violating nuclear forces: quantum chromodynamics vacuum angle (theta) over bar and quark chromo-EDMs. The equilibrium structure of AcOH+ in the ground and the four lowest excited electronic states was found to be linear. The calculated Franck-Condon factors and transition dipole moments indicate that the laser cooling using an optical cycle involving the first excited state is possible for the trapped AcOH+ ions with the Doppler limit estimated to be similar to 4 nK. The lifetime of the (0, 11, 0) excited vibrational state considered as a working one for MQM and eEDM search experiments is estimated to be similar to 0.4 s.