Parity violation effects in diatomics

Kozlov, M. G.; Labzowsky, L. N.

doi:10.1088/0953-4075/28/10/008

Cited by 292 publications

(303 citation statements)

References 48 publications

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“…These are suppressed in the Standard Model (SM), making C 2u,d difficult to measure and at present perhaps the most poorly characterized parameters in the SM [6]. However, because of this suppression, even moderately precise measurements of C 2u,d could be sensitive to new physics at TeV energy scales [7].Our method to measure NSD-PV exploits the properties of diatomic molecules [8,9,10] to amplify the observable signals. Rotational/hyperfine (HF) levels of opposite parity can be mixed by NSD-PV interactions, and are inherently close in energy.…”

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confidence: 99%

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Using Molecules to Measure Nuclear Spin-Dependent Parity Violation

et al. 2008

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Nuclear spin-dependent parity violation arises from weak interactions between electrons and nucleons, and from nuclear anapole moments. We outline a method to measure such effects, using a Stark-interference technique to determine the mixing between opposite-parity rotational/hyperfine levels of ground-state molecules. The technique is applicable to nuclei over a wide range of atomic number, in diatomic species that are theoretically tractable for interpretation. This should provide data on anapole moments of many nuclei, and on previously unmeasured neutral weak couplings.PACS numbers: 32.80. Ys, 12.15.Mm, 21.10.Ky Up to now, atomic parity violation (PV) experiments have primarily focused on the PV effect arising from the weak charge of the nucleus Q W [1], a nuclear spinindependent quantity that parameterizes the electroweak neutral coupling between electron axial-and nucleon vector-currents (A e V n ). Here we propose a highly sensitive and widely applicable technique to measure nuclear spin-dependent (NSD) PV effects. Such effects arise primarily from two underlying causes. The first is the nuclear anapole moment, a P-odd magnetic moment induced by weak interactions within the nucleus, which couples to the spin of a penetrating electron [2]. Measurements of anapole moments can provide useful data on purely hadronic PV interactions [3,4]. So far, only one nuclear anapole moment has been measured, in 133 Cs [5]. The second source of NSD-PV is the electroweak neutral coupling between electron vector-and nucleon axialcurrents (V e A n ). This can be parameterized by two constants, C 2u,d , which describe the V e A n couplings to up and down quarks. These are suppressed in the Standard Model (SM), making C 2u,d difficult to measure and at present perhaps the most poorly characterized parameters in the SM [6]. However, because of this suppression, even moderately precise measurements of C 2u,d could be sensitive to new physics at TeV energy scales [7].Our method to measure NSD-PV exploits the properties of diatomic molecules [8,9,10] to amplify the observable signals. Rotational/hyperfine (HF) levels of opposite parity can be mixed by NSD-PV interactions, and are inherently close in energy. Accessible laboratory magnetic fields can Zeeman-shift these levels to degeneracy, dramatically enhancing the state mixing. The matrix element (m.e.) of the NSD-PV interaction can be measured with a Stark-interference technique of demonstrated sensitivity [11]. Use of ground-state molecules leads to enhanced resolution because of their long lifetimes [11,12]. (Two recent papers also proposed measuring NSD-PV in the ground state HF levels of heavy alkali atoms [13].) The technique is applicable to a wide class of molecules and hence to NSD-PV couplings to the variety of nuclei within them. We specifically consider diatomic molecules with a single valence electron in a 2 Σ electronic state. These are the molecular equivalent of alkali atoms, with a simple, regular structure of rotational/HF levels. This makes it possible to re...

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“…However, for simplicity in the present discussion we assume c ≪ γ, b, so that the decoupled basis states are, to good approximation, the energy eigenstates. The Zeeman effect is dominated by the coupling to S, with approximate Hamiltonian [10] H Z ∼ = −gµ B S · B, where g ∼ = −2 and µ B is the Bohr magneton. Oppositeparity levels |ψ…”

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Using Molecules to Measure Nuclear Spin-Dependent Parity Violation

et al. 2008

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“…Ultracold chemical reactions between polar molecules have been discussed [5], and might be controlled using electric fields [6]. Finally, the sensitivity of current moleculebased searches for violations of fundamental symmetries [7] might be increased to unprecedented levels.Cold, trapped polar molecules have so far only been produced using either buffer-gas cooling [8] or Starkslowing [9], at temperatures of ∼10-100 mK [8,9]. This is much higher than the ∼1-100 µK accessible with atoms, and attempts to bridge this gap with evaporative cooling may run afoul of predicted molecular Feshbach resonances [10] or inelastic losses [11].…”

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Production of Ultracold, PolarRbCs*Molecules via Photoassociation

et al. 2004

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We have produced ultracold, polar RbCs * molecules via photoassociation in a laser-cooled mixture of Rb and Cs atoms. Using a model of the RbCs * molecular interaction which reproduces the observed rovibrational structure, we infer decay rates in our experiments into deeply bound X 1 Σ + ground state RbCs vibrational levels as high as 5×10 5 s −1 per level. Population in such deeply bound levels could be efficiently transferred to the vibrational ground state using a single stimulated Raman transition, opening the possibility to create large samples of stable, ultracold polar molecules.PACS numbers: 32.80. Pj, 33.80.Ps, 34.50.Gb, 34.50.Rk Ultracold polar molecules, due to their strong, longrange, anisotropic dipole-dipole interactions, may provide access to qualitatively new regimes previously inaccessible to ultracold atomic and molecular systems. For example, they might be used as the qubits of a scalable quantum computer [1]. New types of highly-correlated many-body quantum states could become accessible such as BCS-like superfluids [2], supersolid and checkerboard states [3], or "electronic" liquid crystal phases [4]. Ultracold chemical reactions between polar molecules have been discussed [5], and might be controlled using electric fields [6]. Finally, the sensitivity of current moleculebased searches for violations of fundamental symmetries [7] might be increased to unprecedented levels.Cold, trapped polar molecules have so far only been produced using either buffer-gas cooling [8] or Starkslowing [9], at temperatures of ∼10-100 mK [8,9]. This is much higher than the ∼1-100 µK accessible with atoms, and attempts to bridge this gap with evaporative cooling may run afoul of predicted molecular Feshbach resonances [10] or inelastic losses [11].Another approach is to extend well-known techniques for producing ultracold (non-polar) homonuclear diatomic molecules in binary collisions of ultracold atoms, either through photoassociation [12,13,14,15,16], or Feshbach resonance [17,18]. In these methods, the translational and rotational temperatures of the molecules are limited only by the initial atomic sample, possibly providing access all the way to the quantum-degenerate regime [15,18]. An important limitation, however, is that the molecules are typically formed in weakly bound vibrational levels near dissociation, which may have vanishing electric dipole moments [19], and are unstable with respect to inelastic collisions [10,11,15]; therefore, a method for transferring them to the vibrational ground state is desirable [14].Several authors have discussed the extension of these methods to the formation of (heteronuclear) polar molecules in collisions between different atomic species [20,21,22,23]. In recent experiments NaCs + and RbCs + ions formed in the presence of near-resonant light have indeed been observed in small numbers [21]; however, these observations did not permit an analysis of their formation mechanism, nor demonstrate a method for producing neutral, ultracold polar molecules.In this Letter, we ...

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“…A very useful semiempirical expression for K ∼ α 2 Z 3 is proposed in [20] that is well working for s, p electrons though it is questionable for f electrons. E eff is given by [21][22][23]):…”

Section: Methodsmentioning

confidence: 99%

Enhancement of the electron electric dipole moment in Eu2+

et al. 2011

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Towards the search of electron electric dipole moment: correlation calculations of the P,T-violation effect in the Eu ++ cation. Recently the Eu0.5Ba0.5TiO3 solid was suggested as a promising candidate for experimental search of the electron electric dipole moment. To interpret the results of this experiment one should calculate the effective electric field acting on an unpaired (spin-polarized) electrons of europium cation in the crystal because the value of this field cannot be measured experimentally. The Eu ++ cation is considered in the paper in the uniform external electric field Eext as our first and simplest model simulating the state of europium in the crystal. We have performed high-level electronic structure correlation calculation using coupled clusters theory (and scalar-relativistic approximation for valence and outer core electrons at the molecular pseudopotential calculation stage that is followed by the four-component spinor restoration of the core electronic structure) to evaluate the enhancement coefficient K = E eff /Eext (where Eext is the applied external electric field and E eff is the induced effective electric field acting on an unpaired electron in Eu ++ ). A detailed computation analysis is presented. The calculated value of K is -4.6.

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Parity violation effects in diatomics

Cited by 292 publications

References 48 publications

Using Molecules to Measure Nuclear Spin-Dependent Parity Violation

Using Molecules to Measure Nuclear Spin-Dependent Parity Violation

Production of Ultracold, PolarRbCs*Molecules via Photoassociation

Enhancement of the electron electric dipole moment in Eu2+

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