The current status of electric dipole moments of diamagnetic atoms which involves the synergy between atomic experiments and three different theoretical areas -particle, nuclear and atomic is reviewed. Various models of particle physics that predict CP violation, which is necessary for the existence of such electric dipole moments, are presented. These include the standard model of particle physics and various extensions of it. Effective hadron level combined charge conjugation (C) and parity (P) symmetry violating interactions are derived taking into consideration different ways in which a nucleon interacts with other nucleons as well as with electrons. Nuclear structure calculations of the CP-odd nuclear Schiff moment are discussed using the shell model and other theoretical approaches. Results of the calculations of atomic electric dipole moments due to the interaction of the nuclear Schiff moment with the electrons and the P and time-reversal (T) symmetry violating tensor-pseudotensor electron-nucleus are elucidated using different relativistic many-body theories. The principles of the measurement of the electric dipole moments of diamagnetic atoms are outlined. Upper limits for the nuclear Schiff moment and tensor-pseudotensor coupling constant are obtained combining the results of atomic experiments and relativistic many-body theories. The coefficients for the different sources of CP violation have been estimated at the elementary particle level for all the diamagnetic atoms of current experimental interest and their implications for physics beyond the standard model is discussed. Possible improvements of the current results of the measurements as well as quantum chromodynamics, nuclear and atomic calculations are suggested. .+y Nuclear tests of fundamental interactions and symmetries -31.15.ve Electron correlation calculations for atoms and ions: ground state PACS Higgs doublet modelsThe Higgs boson was recently discovered [4,5], but the detailed Higgs potential is still unknown. There are currently many well-motivated extensions of the Higgs sector BSM. The most well-known one is the two-Higgs doublet model (2HDM), and extensive studies have been performed [79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97].As the Higgs boson has a small coupling with light fermions, the one-loop level fermion EDM and the CP-odd four-fermion interactions are suppressed in 2HDM [98,99]. The leading contribution to the elementary level CP violation contributing to the EDM is the two-loop level Barr-Zee type diagram [79] [ Fig. 4 (b)], enhanced by the large Yukawa coupling of the top quark of the inner loop. The Barr-Zee type diagram contribution to the EDM of SM fermion can be written as [79]
The electric dipole moment (EDM) is an excellent probe of new physics beyond the standard model of particle physics. The EDM of light nuclei is particularly interesting due to the high sensitivity to the hadron level CP violation. In this proceedings contribution, we investigate the mechanism of the generation of the EDM for several light nuclei and the prospect for the discovery of new physics.
We calculate for the first time the electric dipole moment (EDM) of the 6 Li nucleus within the α + p + n three-body cluster model using the Gaussian expansion method, assuming the one meson exchange P, CP-odd nuclear forces. It is found that the EDM of the 6 Li is 2 times more sensitive on the isovector pion exchange P, CP-odd nuclear force than the deuteron EDM, due to the CP-odd interaction between the nucleons and the α cluster. The 9 Be EDM is also calculated in the same framework as an α + α + n three-body system. We also test the ab initio calculation of the EDM of the deuteron, 3 H and 3 He nuclei using the realistic Argonne v18 nuclear force. In the ab initio calculations, good agreements with previous studies are obtained. We finally discuss the prospects for the new physics beyond the standard model.
We calculate the scalar and tensor charges of the nucleon in 2+1-flavor lattice QCD, for which the systematics of the renormalization of the disconnected diagram is well controlled. Numerical simulations are performed at a single lattice spacing a = 0.11 fm. We simulate four pion masses, which cover a range of m π ∼ 290 -540 MeV, and a single strange quark mass close to its physical value. The statistical accuracy is improved by employing the so-called low-mode averaging technique and the truncated solver method. We study up, down, and strange quark contributions to the nucleon charges by calculating disconnected diagrams using the all-to-all quark propagator.Chiral symmetry is exactly preserved by using the overlap quark action to avoid operator mixing among different flavors, which complicates the renormalization of scalar and tensor matrix elements and leads to possibly large contamination to the small strange quark contributions. We also study the nucleon axial charge with a contribution from the disconnected diagram. Our results are in reasonable agreement with experiments and previous lattice studies.
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