scholarly journals Vanishing or non-vanishing rainbow? Reduction formulas of electric dipole moment

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Motoko Fujiwara ◽  
Junji Hisano ◽  
Takashi Toma
Keyword(s):  
Electric Dipole ◽  
Dipole Moments ◽  
Form Factors ◽  
The Other ◽  
Vertex Correction ◽  
Electric Dipole Moments ◽  
Self Energy ◽  
The Standard Model ◽  
General Setup ◽  
Exact Cancellation

Abstract In this paper, we derive a simplified formula of electric dipole moments (EDMs) of a fermion. In the Standard Model, it is well-known that non-trivial cancellations between some rainbow-type diagrams induced by W boson exchanges occur in the calculation of the neutron EDM at the two-loop level due to the gauge symmetry. The fermion self-energy and the vertex correction are related through the Ward-Takahashi identity, and this relation causes the exact cancellation of the EDM. We derive EDM formulas for a more general setup by introducing the form factors for the fermion self-energy and the vertex correction so that the derived formulas can be applicable to a larger class of models. We conclude that the non-zero EDM contributions are induced from rainbow-type diagrams with the chirality flipping effects for internal fermions. We also discuss the other possible generalization of the EDM calculation which is applicable to the other classes of models.

scholarly journals Filling the gaps between model predictions and their prerequisites in electric dipole moments

2016 ◽  
Vol 31 (14n15) ◽  
pp. 1650082 ◽  
Author(s):  
Takeshi Fukuyama ◽  
Koichiro Asahi
Keyword(s):  
Electric Dipole ◽  
Model Building ◽  
Dipole Moments ◽  
The Other ◽  
Beyond The Standard Model ◽  
Correct Interpretation ◽  
Electric Dipole Moments ◽  
The Standard Model ◽  
Model Predictions ◽  
Theoretical Predictions

We clarify the conditions or assumptions under which theoretical predictions of various models beyond the standard model give mainly in electric dipole moments. The correct interpretation of those conditions seems to be indispensable to the refinements of model building as well as to the mutual reliance in experimental and theoretical communities. The connections of these analyses to the recent experimental results at the LHC and the other places are also discussed.

scholarly journals Top partner-resonance interplay in a composite Higgs framework

2018 ◽  
Vol 33 (11) ◽  
pp. 1841008 ◽  
Author(s):  
Juan Yepes ◽  
Alfonso Zerwekh
Keyword(s):  
Symmetry Breaking ◽  
Electric Dipole ◽  
Dipole Moments ◽  
Low Energy ◽  
Vector Resonance ◽  
Electric Dipole Moments ◽  
Parameter Spaces ◽  
Standard Model Fermion ◽  
Composite Higgs ◽  
The Standard Model

Guided us by the scenario of weak scale naturalness and the possible existence of exotic resonances, we have explored in a [Formula: see text] Composite Higgs setup the interplay among three matter sectors: elementary, top partners and vector resonances. We parametrize it through explicit interactions of spin-1 [Formula: see text]-resonances, coupled to the [Formula: see text]-invariant fermionic currents and tensors presented in this work. Such invariants are built upon the Standard Model fermion sector as well as top partners sourced by the unbroken [Formula: see text]. The mass scales entailed by the top partner and vector resonance sectors will control the low energy effects emerging from our interplaying model. Its phenomenological impact and parameter spaces have been considered via flavor-dijet processes and electric dipole moments bounds. Finally, the strength of the Nambu–Goldstone symmetry breaking and the extra couplings implied by the top partner mass scales are measured in accordance with expected estimations.

scholarly journals CP VIOLATION IN SUPERSYMMETRIC THEORIES

2003 ◽  
Vol 18 (10) ◽  
pp. 1697-1732 ◽  
Author(s):  
SHAABAN KHALIL
Keyword(s):  
Dipole Moment ◽  
Cp Violation ◽  
Standard Model ◽  
Electric Dipole ◽  
Dipole Moments ◽  
Neutron Electric Dipole Moment ◽  
Cp Asymmetry ◽  
Electric Dipole Moments ◽  
The Standard Model ◽  
Supersymmetric Theories

We review the present status of the CP violating problem in supersymmetric extensions of the standard model. We analyze the constraints imposed by the experimental limits of the electron, neutron, and mercury electric dipole moments on the supersymmetric CP phases and show that only the scenarios with flavour-off-diagonal CP violation remain attractive. These scenarios require Hermitian Yukawa matrices which naturally arise in models with left–right symmetry or a SU(3) flavour symmetry. In this case, εK and ε′/ε can be saturated by a small non-universality of the soft scalar masses through the gluino and chargino contributions respectively. The model also predicts a strong correlation between A CP (b → sγ) and the neutron electric dipole moment. In this framework, the standard model gives a the leading contribution to the CP asymmetry in B → ψKS decay, while the dominant chargino contribution to this asymmetry is < 0.2. Thus, no constraint is set on the non-universality of this model by the recent BaBar and Belle measurements.

scholarly journals Exploring Supersymmetric CP Violation after LHC Run 2 with Electric Dipole Moments and B Observables

2020 ◽  
Vol 80 (7) ◽  
Author(s):  
A. Arbey ◽  
J. Ellis ◽  
F. Mahmoudi
Keyword(s):  
Electric Dipole ◽  
Dipole Moments ◽  
Mass Difference ◽  
Geometric Approach ◽  
Supersymmetric Extension ◽  
Electric Dipole Moments ◽  
Central Value ◽  
Upper Limits ◽  
The Standard Model ◽  
Model Predictions

Abstract We consider the prospects for measuring distinctive signatures of the CP-violating phases in the minimal supersymmetric extension of the Standard Model (MSSM) in light of the limits on sparticle masses from searches at the LHC. We use the code to evaluate model predictions and scan the parameter space using a geometric approach that maximizes CP-violating observables subject to the current upper limits on electric dipole moments (EDMs). We focus on the possible CP-violating asymmetry $$A_{\mathrm{CP}}$$ACP in $$b \rightarrow s \gamma $$b→sγ decay and on a possible CP-violating contribution to the $$B_s - {\overline{B}}_s$$Bs-B¯s mass difference $$\Delta M^{NP}_{B_s}$$ΔMBsNP, as well as future measurements of the EDMs of the proton, neutron and electron. We find that the current LHC and EDM limits are consistent with values of $$A_{\mathrm{CP}}$$ACP, $$\Delta M^{NP}_{B_s}$$ΔMBsNP and the proton EDM that are measurable with the Belle-II detector, LHCb and a proposed measurement of the proton EDM using a storage ring, respectively. Measurement of a non-zero proton EDM would constrain $$A_{\mathrm{CP}}$$ACP significantly, but it and a CP-violating contribution to $$\Delta M^{NP}_{B_s}$$ΔMBsNP could still be measurable, along with neutron and electron EDMs. A more accurate measurement of $$A_{\mathrm{CP}}$$ACP with the current central value would favour stop and chargino masses within reach of future LHC runs as well as a potentially measurable value of $$\Delta M^{NP}_{B_s}$$ΔMBsNP.

A REVIEW OF CP VIOLATION IN ATOMS

1993 ◽  
Vol 08 (02) ◽  
pp. 209-236 ◽  
Author(s):  
S.M. BARR
Keyword(s):  
Cp Violation ◽  
Standard Model ◽  
Electric Dipole ◽  
Dipole Moments ◽  
Beyond The Standard Model ◽  
Electric Dipole Moments ◽  
The Standard Model ◽  
The Subject

The subject of atomic and molecular electric dipole moments is reviewed from the perspective of currently interesting theories of CP violation beyond the standard model.

scholarly journals Permanent electric dipole moments of single-, two- and three-nucleon systems

2017 ◽  
Vol 26 (01n02) ◽  
pp. 1740031 ◽  
Author(s):  
Andreas Wirzba ◽  
Jan Bsaisou ◽  
Andreas Nogga
Keyword(s):  
Electric Fields ◽  
Electric Dipole ◽  
Dipole Moments ◽  
New Physics ◽  
Finite System ◽  
Light Nuclei ◽  
Window Of Opportunity ◽  
Matrix Elements ◽  
Electric Dipole Moments ◽  
The Standard Model

A nonzero electric dipole moment (EDM) of the neutron, proton, deuteron or helion, in fact, of any finite system necessarily involves the breaking of a symmetry, either by the presence of external fields (i.e., electric fields leading to the case of induced EDMs) or explicitly by the breaking of the discrete parity and time-reflection symmetries in the case of permanent EDMs. We discuss two theorems describing these phenomena and report about the cosmological motivation for an existence of [Formula: see text] breaking beyond what is generated by the Kobayashi–Maskawa mechanism in the Standard Model and what this might imply for the permanent EDMs of the nucleon and light nuclei by estimating a window of opportunity for physics beyond what is currently known. Recent — and in the case of the deuteron even unpublished — results for the relevant matrix elements of nuclear EDM operators are presented and the relevance for disentangling underlying New Physics sources is discussed.

scholarly journals Coulomb excitation of pear-shaped nuclei

2019 ◽  
Vol 223 ◽  
pp. 01007
Author(s):  
Peter Butler ◽  
Liam Gaffney ◽  
Pietro Spagnoletti ◽  
Joonas Konki ◽  
Marcus Scheck ◽  
...  
Keyword(s):  
Electric Dipole ◽  
Particle Physics ◽  
Coulomb Excitation ◽  
Dipole Moments ◽  
Large Body ◽  
Quantum States ◽  
Beyond The Standard Model ◽  
Electric Dipole Moments ◽  
Atomic Nuclei ◽  
The Standard Model

There is a large body of evidence that atomic nuclei can undergo octupole distortion and assume the shape of a pear. This phenomenon is important for measurements of electric-dipole moments of atoms, which would indicate CP violation and hence probe physics beyond the Standard Model of particle physics. Isotopes of both radon and radium have been identified as candidates for such measurements. Here, we have observed the low-lying quantum states in 224Rn and 226Rn by accelerating beams of these radioactive nuclei. We show that radon isotopes undergo octupole vibrations but do not possess static pear-shapes in their ground states. We conclude that radon atoms provide less favourable conditions for the enhancement of a measurable atomic electric-dipole moment.

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