Probing exotic phenomena at the interface of nuclear and particle physics with the electric dipole moments of diamagnetic atoms: A unique window to hadronic and semi-leptonic CP violation

Abstract

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]

Exploring dynamical CP violation induced baryogenesis by gravitational waves and colliders

“…3, where the region below the dotted blue lines is excluded by the EDM experiments. We also consider constraints from neutron EDM [72][73][74] and mercury EDM [75,76]. But, through our calculation, we find that limits from current neutron and mercury EDM experiments are weaker than electron EDM.…”

Extracting the σ-term from low-energy pion-nucleon scattering

“…to be added to (10). Here, F V π denotes the electromagnetic form factor of the pion, F 1/2 the Dirac/Pauli form factor of the proton, e 2 = 4πα,…”

“…These scalar couplings not only emerge as fundamental QCD parameters, measuring the amount of the nucleon mass generated by up-and down-quarks, but also determine nucleon matrix elements required in the search for physics beyond the Standard Model, e.g. in the direct detection of dark matter [2][3][4], searches for lepton flavor violation in µ → e conversion in nuclei [5,6], or electric dipole moments [7][8][9][10]. Such nucleon matrix elements corresponding to an interaction channel not present in the Standard Model as an external current are difficult to constrain from experiment, often leaving abinitio calculations in lattice QCD as the only viable approach.…”

Role of the Soffer bound in determination of transversity and the tensor charge

“…Studies of transversity and the tensor charge are important for Beyond Standard Model (BSM) searches. Indeed, the isovector tensor charge, g T , is related to potential tensor interactions in the electroweak sector [19][20][21][22], and it is usually calculated on the lattice, as a matrix element over the full x range, or by integrating the extracted transversity functions from phenomenological analyses. With respect to lattice QCD estimates, the latest phenomenological extractions of the transversity function [2,3,5,9,10,18,23] seem to show a tension [24] on the estimated values of g T as well as on individual contributions from up, δu, and down, δd, quarks (see Eq.…”