TaO+^+, a Candidate Molecular Ion in Search of Physics Beyond the Standard Model

The TaO$^+$ molecular ion is proposed as a candidate system for detecting signatures of charge parity (${\cal{CP}}$) violating physics beyond the standard model of elementary particles. The electron electric dipole moment (EDM) effective electric field $E_{\text{eff}} = 20.2 \left[\frac{\rm GV}{\rm cm}\right]$, the nucleon-electron scalar-pseudoscalar (ne-SPS) interaction constant $W_{S} = 17.7$ [kHz] and the nuclear magnetic quadrupole interaction constant $W_M = 0.45$ [$\frac{10^{33} {\text{Hz}}}{e\, {\text{cm}}^2}$] are found to be sizeable ${\cal{P,T}}$-odd enhancements. The ratio of the leptonic and semi-leptonic enhancements differs strongly from the one for the ThO system which may provide improved limits on the electron EDM, $d_e$, and the SPS coupling constant, $C_S$. TaO$^+$ is found to have a ${^3\Delta_1}$ electronic ground state like the previously proposed ThF$^+$ molecular ion, but an order of magnitude smaller parallel G-tensor component which makes it less vulnerable to systematic errors in experiment.Comment: 9 pages, 1 figur

P,T-Odd Interactions in Atomic 129{}^{129}Xe and Phenomenological Applications

We calculate interaction constants for the contributions from \PT-odd scalar-pseudoscalar and tensor-pseudotensor operators to the electric dipole moment of ${}^{129}$Xe, for the first time in case of the former, using relativistic many-body theory including the effects of dynamical electron correlations. These interaction constants are necessary ingredients to relating the corresponding measurements to fundamental parameters in models of physics beyond the Standard Model. We obtain $\alpha_{C_S} = \left( 0.71 \pm 0.18 \right) [10^{-23}\, e~\text{cm}]$ and \alpha_{C_T}= \left( 0.520 \pm 0.049 \right) [10^{-20}\, \left_{\text{Xe}}\, e~\text{cm}], respectively. We apply our results to test a phenomenological relation between the two quantities, commonly used in the literature, and discuss their present and future phenomenological impact.Comment: 25 pages, 0 figure

RIGOROUS RELATIVISTIC METHODS FOR ADDRESSING al{P}}- AND al{T}}-NONCONSERVATION IN HEAVY-ELEMENT MOLECULES

Author Institution: Laboratoire de Chimie et Physique Quantiques, Universite Paul Sabatier Toulouse 3, Toulouse, FranceA new and rigorous method for accurate ab-initio calculations of the electron electric dipole moment al{P,T}}-odd interaction constant is presented. The approach uses string-based Configuration Interaction wavefunctions[t]{15.0cm} S.~Knecht, H.~J.~{\AA}.~Jensen and T.~Fleig \textit{J.~Chem.~Phys.} nderline{\textbf{132}}, 014108 (2010) \\ T.~Fleig, H.~J.~{\AA}.~Jensen, J.~Olsen and L.~Visscher \textit{J.~Chem.~Phys.} nderline{\textbf{124}}, 104106 (2006) \end{minipage}} and Dirac four-component spinors as one-particle basis functions, and the al{P,T}}-odd constant is obtained as an expectation value over these correlated wavefunctions. The method has been applied to the HfF$^+$ molecular ion to determine spectroscopic constants for four low-lying electronic states. For one of these states ($\Omega = 1$) we have determined a new accurate benchmark value nderline{\textbf{XXX}}, XXXX (submitted).} for the effective electric field $E_{\rm eff}$ correlating $34$ valence and outer atomic core electrons and using wavefunction expansions with nearly $5 \cdot 10^8$ coefficients. For the $\Omega = 1$ state of the ThO molecule the first ab-initio result for the electron EDM interaction constant is presented. Aspects of modern all-electron relativistic many-body approaches applicable to both atoms and molecules will be discussed, including perspectives for the treatment of other interesting candidate systems and al{P}}- or al{P,T}}-non-conserving effects in molecular systems. %Zero-kinetic-energy (ZEKE) photoelectron spectroscopy was used to probe the vibrational levels in the ground electronic state of the chlorobenzene cation using a two-color photoionization scheme via the S${_1}$ electronic state of the neutral nderline{\textbf{102}}(12), XXXX March 1995.}. Exciting through different S${_1}$ vibrational levels has revealed mixing of some S${_1}$ normal coordinates in the ground state of the cation. A previously-identified Fermi resonance in the S${_1}$ state of the neutral is also confirmed by the ZEKE spectra. The adiabatic ionization energy is measured as $73\,170\pm5$\,cm$^{-1}$

Candidate Molecules for Next-Generation Searches of Hadronic Charge-Parity Violation

We systematically study a set of strongly polar heteronuclear diatomic molecules composed of laser-coolable atoms for their suitability as sensitive probes of new charge-parity violation in the hadron sector of matter. Using relativistic general-excitation-rank configuration interaction theory we single out the molecule francium-silver (FrAg) as the most promising system in this set and calculate its nuclear Schiff-moment interaction constant to $W^\mathrm{FrAg}_{SM}(\mathrm{Fr}) = 30168 \pm 2504\mathrm{a.u.}$ for the target nucleus Fr. Our work includes the development of system-tailored atomic Gaussian basis sets for the target atom in each respective molecule.Comment: 16 pages, 10 table