P-odd Interaction Research Articles

Enhanced nuclear Schiff moment in stable and metastable nuclei

Nuclei with static intrinsic octupole deformation or a soft octupole vibrational mode lead to strongly enhanced collective nuclear Schiff? moments. Interaction between electrons and these Schiff moments produce enhanced time reversal (T) and parity (P) violating electric dipole moments (EDM) in atoms and molecules. Corresponding experiments may be used to test CP-violation theories predicting T,P-violating nuclear forces and to search for axions. Nuclear octupole deformations are predicted in many short lived isotopes. This paper investigates octupole deformations in stable and very long lifetime nuclei such as 153Eu, 235U, 237Np and 227Ac, which can ease atomic experiments substantially. The estimates of the enhanced Schiff? moments, atomic electric dipole momentsand T, P-odd interaction constants in molecules containing these nuclei are presented.

Nuclear anapole moment interaction in BaF from relativistic coupled-cluster theory

We present high accuracy relativistic coupled cluster calculations of the P-odd interaction coefficient $W_A$ describing the nuclear anapole moment effect on the molecular electronic structure. The molecule under study, BaF, is considered a promising candidate for the measurement of the nuclear anapole moment, and the preparation for the experiment is now underway [Altunas et al., Phys. Rev. Lett. 120, 142501 (2018)]. Influence of various computational parameters (size of the basis set, treatment of relativistic effects, and treatment of electron correlation) on the calculated $W_A$ coefficient is investigated and a recommended value of 147.7 Hz with an estimated uncertainty of 1.5% is proposed.

Search for parity- and time-and-parity–violation effects in lead monofluoride (PbF):Ab initiomolecular study

The relativistic coupled-clusters method combined with the generalized relativistic effective core potential approach and nonvariational one-center restoration technique is applied to evaluation of parameters of spin-rotational effective Hamiltonian in lead monofluoride to study the effects of violation of time-reversal invariance (T) and space parity (P) in PbF. The obtained hyperfine structure constants, A$_{||}$=9942 MHz and A$_{\perp}$=-7174 MHz are stable with respect to the improvement of the correlation treatment and they are in a very good agreement with the experimental data, A$_{||}$=10147 MHz and A$_{\perp}$=-7264 MHz [PRA {\bf 84}, 022508 (2011)]. This is essential to the important task of verifying the value of effective electric field \Eeff =40 GV/cm, the parameter of P-odd interaction $W_{P}$=-1213 Hz and the parameter of T,P-odd pseudoscalar$-$scalar electron$-$nucleus interaction $W_{T,P}$=91 kHz, which are of primary interest in the paper.

Limiting P-odd interactions of cosmic fields with electrons, protons, and neutrons.

We propose methods for extracting limits on the strength of P-odd interactions of pseudoscalar and pseudovector cosmic fields with electrons, protons, and neutrons, by exploiting the static and dynamic parity-nonconserving amplitudes and electric dipole moments they induce in atoms. Candidates for such fields are dark matter (including axions) and dark energy, as well as several more exotic sources described by Lorentz-violating standard model extensions. Atomic calculations are performed for H, Li, Na, K, Rb, Cs, Ba(+), Tl, Dy, Fr, and Ra(+). From these calculations and existing measurements in Dy, Cs, and Tl, we constrain the interaction strengths of the parity-violating static pseudovector cosmic field to be 7 × 10(-15) GeV with an electron, and 3 × 10(-8) GeV with a proton.

Searches for possible T-odd and P-odd interactions of mesoscopic range using polarized nuclei and nonmagnetic masses

Searches for possible T-odd and P-odd interactions of mesoscopic range using polarized nuclei and nonmagnetic masses

Ab initio calculation of the P-odd interaction constant WA in YbF: a relativistic configuration-interaction approach

We present the result for the P-odd electron–nucleus interaction constant WA of the YbF molecule in the ground (2∑1/2) state, computed by using a fully relativistic restricted active space configuration-interaction method, which yields the result WA = 543 Hz, in reasonable agreement with previous calculations. This result will be useful for experimentalists proposing new experiments in the search for nuclear-spin-dependent parity-nonconserving effects in the YbF molecule.

Proposed search forT-odd,P-even interactions in spectra of chaotic atoms

Violation of fundamental symmetries in atoms is the subject of intense experimental and theoretical interest. P-odd, T-even transitions have been observed and are in excellent agreement with electroweak theory. Searches for permanent electric dipole moments have placed bounds on T-odd, P-odd interactions, constraining proposed extensions to the Standard Model of elementary particles. Here we propose a new search for T-odd, P-even (TOPE) interactions in atoms. We consider open-shell atoms, such as the rare-earth atoms, which have dense, chaotic excitation spectra with strong level repulsion. The strength of the level repulsion depends on the underlying symmetries of the atomic Hamiltonian. TOPE interactions lead to enhanced level repulsion. We demonstrate how a statistical analysis of many chaotic spectra can determine the strength of level repulsion; in particular, the variance of the number of levels in an energy range has been shown to be a useful measure. We estimate that, using frequency comb spectroscopy, a sufficient number of chaotic levels could be measured to match or exceed the current experimental bounds on TOPE interactions.

Parity Violating Energy Shifts in Atoms, I

We present a study of parity (P) violating contributions to the eigenenergies of stationary systems containing atoms in spatially inhomogeneous external electric fields. In this context the subtle interplay of P-violation and time reversal (T) invariance plays an important role. If the entire field configuration is chosen to exhibit chirality the energies are in general shifted by pseudoscalar contributions which change sign under a planar reflection of the field. In part I we consider sudden variations of the fields and calculate P-violating energy shifts using perturbation theory. In part II the adiabatic case will be treated and the connection to geometrical (Berry-) phases will be elucidated. To calculate the effects we use the standard model of elementary particle physics where the P-odd interaction arises through the exchange of Z-bosons between the quarks in the nucleus and the atomic electrons. We consider in detail hydrogen-like systems in unstable levels of principal quantum number n = 2. We study atoms with vanishing nuclear spin like $$_{1}^{1}{\rm He}^{+}$$ and with nuclear spin I = 1/2 like $$_{1}^{1}{\rm H}$$ . The nominal order of P-violating effects is 10−5...10−9 Hz which is determined by the mixing of the 2S1/2 and 2P1/2 states. However we point out that with certain configurations of the external fields, it is possible to enhance the P-violating energy shifts dramatically! Instead of energy shifts linear in the P-violation parameters we get then shifts proportional to the square root of these parameters. Numerically we find such energy shifts which only appear for unstable states to be of order 10−5...1 Hz. Under a reversal of the handedness of the external field configuration these P-violating shifts get multiplied by a phase factor i, i.e. the shifts in the real and imaginary part of the complex eigenenergies are exchanged. Application of our technique to hydrogen-like atoms with a nucleus of spin I = 1/2 yields P-violating energy shifts which are very sensitive to the nuclear spin dependent P-odd force, which receives a rather large contribution from the polarized strange quark density in polarized nuclei. Thus, a measurement of these energy shifts could provide an important tool to elucidate nuclear properties connected to the so called “spin crisis”. We also present a method for treating degenerate perturbation theory which combines advantages of both, Kato’s and Bloch’s methods.

Dyons as a source of CP and time-reversal invariance violation: electric dipole moments and K-meson decays

We consider a mechanism by which dyons (electrically charged magnetic monopoles) can produce both a T- and P-odd (i.e. time-reversal invariance and parity violating) mixed polarizability (defined by E = -E . B, where E is the energy change when electric (E) and magnetic (B) fields are applied to a system) and a T- and P-odd interaction between two particles: 15 122, where the i are electron and quark spinors. The latter can create atomic and neutron electric dipole moments. From experimental bounds on these we find limits on the properties of dyons. The contribution of dyons to CP violation in K-meson decays is also estimated.

Time invariance violating nuclear electric octupole moments

The existence of a nuclear electric octupole moment (EOM) requires both parity and time invariance violation. The EOM{close_quote}s of odd Z nuclei that are induced by a particular T- and P-odd interaction are calculated. We compare such octupole moments with the collective EOM{close_quote}s that can occur in nuclei having a static octupole deformation. A nuclear EOM can induce a parity- and time-invariance-violating atomic electric dipole moment, and the magnitude of this effect is calculated. The contribution of a nuclear EOM to such a dipole moment is found, in most cases, to be smaller than that of other mechanisms of atomic electric dipole moment production. {copyright} {ital 1997} {ital The American Physical Society}