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The scalar-pseudoscalar (S-PS) interaction, which has been predicted between the electrons and nuclei of atoms and molecules, violates parity (P) and time (T) reversal symmetries. The electric dipole moment of the electron (eEDM) and the S-PS interaction together give rise to an energy shift in paramagnetic polar molecules, which in principle can be measured. The determination of the S-PS interaction constant, k s,A , for an atom A could be a sensitive probe of physics beyond the standard model (SM). The upper limit for it can be obtained by combining the results of the measured energy shift mentioned above and the accurate quantum chemical calculation of the S-PS coefficient, W s,A. In this work, we use a method based on the four-component relativistic coupled-cluster singles and doubles (RCCSD) method to calculate this coefficient for YbF, one of the most promising candidates for the search of the eEDM and the S-PS interaction. We obtain W s,Yb = −40.5 [kHz] with an estimated error of less than 10% for YbF. We also calculate the effective electric field (E eff), the molecular dipole moment (DM), and the parallel component of the hyperfine coupling constant (A //) by the RCCSD method. The discrepancies in the results of these calculations with those of accurate measurements are used to estimate the accuracy of our calculation of W s,Yb.
Heavy polar diatomic molecules are currently one of the leading candidates for probing physics beyond the Standard Model via studies of time-reversal (T) and parity (P) violations. In this work, we analyze the effective electric field (Eeff) that is required for determining the electron electric dipole moment (eEDM), and the scalar-pseudoscalar (S-PS) interaction constant (Ws), in group 12 and group 2 systems. We use a relativistic coupled cluster method for our calculations, and find that group 12 monofluorides have large Eeff and Ws (for example, the values of Eeff and Ws of CnF, the heaviest group 12 fluoride, are 662 GV/cm and 3360 kHz, respectively). The reason for this is the contraction of the valence s and p orbitals due to the weak screening effect of the outermost core's d electron. The calculations of Eeff and Ws show that their ratio, (Ws/Eeff), increases with Z. Based on these results, as well as experimental suitability, we propose SrF and CdF as new candidate molecules for experiment.The electric dipole moment of the electron (eEDM, or de) is a consequence of simultaneous violations of parity (P) and time reversal (T) symmetries [1][2][3][4]. It is of great interest in constraining theories beyond the Standard Model (BSM) of particle physics [5,6], and also in providing insights into the matter-antimatter asymmetry in the Universe [7,8]. To extract the eEDM, experiments use heavy polar diatomic molecules [9][10][11].Also of interest in fundamental physics is the P and T violating scalar-pseudoscalar (S-PS) interaction. This is a type of interaction between electrons and nuclei, but it requires not a scalar Higgs like in the Standard Model, but a Higgs with scalar and pseudoscalar components, for example, in the aligned two-Higgs doublet model [12]. This interaction is also T violating like the eEDM, and can shed light on the baryon asymmetry in the Universe. The coupling constant associated with this interaction is the S-PS interaction constant, ks, and determining it is important for BSM physics, just as in the case of de.In an experiment on a paramagnetic molecule, one measures the shift in its energy, due to de and ks. The energy shift due to eEDM is given by the negative of the product of de and an effective electric field, Eeff. In the case of the S-PS interaction, the quantity analogous to Eeff is the S-PS coefficient, W s . The energy shifts that are experimentally measured have been smaller than their errors so far, and therefore, the eEDM and S-PS interaction have not been discovered yet. Since an experiment actually measures both the eEDM and the S-PS interaction, one actually sets one quantity to zero, and obtains a bound on the other. However, if we measure two energy shifts using two different systems, both the quantities can be obtained without assuming that the other is zero.Molecules with larger Eeff and Ws are experimentally more favorable because they lead to higher sensitivity. According to semi-empirical formulas for atomic enhancement factor K [13] and molecular Eeff [14], not ...
Static electric dipole moments of nondegenerate systems probe mass scales for physics beyond the Standard Model well beyond those reached directly at high energy colliders. Discrimination between different physics models, however, requires complementary searches in atomic-molecular-and-optical, nuclear and particle physics. In this report, we discuss the current status and prospects in the near future for a compelling suite of such experiments, along with developments needed in the encompassing theoretical framework.
Parity-violating energies E PV of the H 2 X 2 (X = O, S, Se, Te, Po) molecules are reported, calculated as analytical expectation values at the relativistic coupled-cluster singles-and-doubles (CCSD) level using property-optimised basis sets. Radiative corrections to the E PV was investigated using effective QED-potentials and found to reach a maximal value of 2.38% for H 2 Po 2 . However, this result depends on the choice of effective self-energy potential and may indicate limitations to their domain of validity.
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