scholarly journals THE TOROID DIPOLE MOMENT OF THE NEUTRINO

1998 ◽  
Vol 13 (30) ◽  
pp. 5257-5277 ◽  
Author(s):  
VLADIMIR M. DUBOVIK ◽  
VALENTIN E. KUZNETSOV
Keyword(s):  
Dipole Moment ◽  
Mass Shell ◽  
Dipole Moments ◽  
Form Factors ◽  
Dispersion Method ◽  
Anapole Moment ◽  
Electromagnetic Interactions ◽  
Loop Approximation ◽  
The Standard Model ◽  
The One

We discuss the third electromagnetic characteristic of the neutrino, i.e. the toroid dipole moment (TDM), in the framework of the Standard Model. The TDM's distinctions from and similarities to an anapole moment are mentioned. The calculations of toroid dipole moments of νe,μ,τ neutrinos have been done by the dispersion method in the one-loop approximation of the SM for the Majorana case and generalized to the Dirac one. We found them to be different from zero in the case of massive as well as massless neutrinos. The behavior of the νe,μ,τ toroid form factors is also presented in the [Formula: see text] range. All external particles are on the mass shell and there are no problems with the physical interpretation of the final result. Some manifestations of the electromagnetic interactions of neutrinos, induced by their toroid moments, are also remarked on.

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 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.

The anapole moment and singlet fields

1988 ◽  
Vol 66 (5) ◽  
pp. 384-384 ◽  
Author(s):  
H. Czyż ◽  
M. Zralek
Keyword(s):  
Gauge Fields ◽  
Static Properties ◽  
Anapole Moment ◽  
Loop Approximation ◽  
Charged Leptons ◽  
The One

We found that the definitions of the static properties of charged leptons within the Glashow–Salem–Weinberg model are equivalent in both the singlet fields and the Rξ gauge fields, at least in the one-loop approximation.

scholarly journals CP violation in neutral lepton transition dipole moment

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Shyam Balaji ◽  
Maura Ramirez-Quezada ◽  
Ye-Ling Zhou
Keyword(s):  
Dipole Moment ◽  
Form Factors ◽  
Transition Dipole Moment ◽  
Threshold Condition ◽  
Neutrino Masses ◽  
Order Unity ◽  
Transition Dipole ◽  
The Standard Model ◽  
Neutral Lepton ◽  
Mixing Matrix

Abstract The CP violation in the neutrino transition electromagnetic dipole moment is discussed in the context of the Standard Model with an arbitrary number of right-handed singlet neutrinos. A full one-loop calculation of the neutrino electromagnetic form factors is performed in the Feynman gauge. A non-zero CP asymmetry is generated by a required threshold condition for the neutrino masses along with non-vanishing CP violating phases in the lepton flavour mixing matrix. We follow the paradiagm of CP violation in neutrino oscillations to parametrise the flavour mixing contribution into a series of Jarlskog-like parameters. This formalism is then applied to a minimal seesaw model with two heavy right-handed neutrinos denoted N1 and N2. We observe that the CP asymmetries for decays into light neutrinos N → νγ are extremely suppressed, maximally around 10−17. However the CP asymmetry for N2→ N1γ can reach of order unity. Even if the Dirac CP phase δ is the only source of CP violation, a large CP asymmetry around 10−5–10−3 is comfortably achieved.

scholarly journals On the Second Dipole Moment of Dirac’s Particle

2021 ◽  
Author(s):  
Engel Roza
Keyword(s):  
Dipole Moment ◽  
Electric Dipole Moment ◽  
Electric Dipole ◽  
Particle Physics ◽  
Critical Survey ◽  
Majorana Particle ◽  
Nuclear Domain ◽  
The Standard Model ◽  
Charge Parity ◽  
The One

An analysis is presented of the possible existence of a second anomalous dipole moment of Dirac&rsquo;s particle next to the one associated with the angular momentum. It includes a discussion why, in spite of his own derivation, Dirac has doubted about its relevancy. It is shown why since then it has been overlooked and why it has vanished from leading textbooks. A critical survey is given on the reasons of its reject, including the failure of attempts to measure and the perceived violations of time reversal symmetry and charge-parity symmetry. It is emphasized that the anomalous electric dipole moment of the pointlike electron (AEDM) is fundamentally different from the quantum field type electric dipole moment of an electron (eEDM) as defined in the standard model of particle physics. The analysis has resulted into the identification of a third type Dirac particle, next to the electron type and the Majorana particle. It is shown that, unlike as in the case of the electron type, its second anomalous dipole moment is real valued and is therefore subject to polarization in a vector field. Examples are given that it may have a possible impact in the nuclear domain and in the gravitational domain.

scholarly journals FLIPPED SU(5), SEESAW SCALE PHYSICS AND DEGENERATE VACUA

2006 ◽  
Vol 21 (14) ◽  
pp. 1151-1160 ◽  
Author(s):  
C. R. DAS ◽  
C. D. FROGGATT ◽  
L. V. LAPERASHVILI ◽  
H. B. NIELSEN
Keyword(s):  
Standard Model ◽  
Effective Potential ◽  
Top Quark ◽  
Multiple Point ◽  
Yukawa Couplings ◽  
Fundamental Scale ◽  
Loop Approximation ◽  
The Standard Model ◽  
Gut Scale ◽  
The One

We investigate the requirement of the existence of two degenerate vacua of the effective potential as a function of the Weinberg–Salam Higgs scalar field norm, as suggested by the multiple point principle, in an extension of the Standard Model including seesaw scale physics. Results are presented from an investigation of an extension of the Standard Model to the gauge symmetry group SU (3)C× SU (2)L× U (1)′×Ũ(1), where U (1)′ and Ũ(1) originate at the seesaw scale M SS , when heavy (right-handed) neutrinos appear. The consequent unification of the group SU (3)C× SU (2)L× U (1)′ into the flipped SU (5) at the GUT scale leads to the group SU (5)×Ũ(1). We assume the position of the second minimum of the effective potential coincides with the fundamental scale, here taken to be the GUT scale. We solve the renormalization group equations in the one-loop approximation and obtain a top-quark mass of 171±3 GeV and a Higgs mass of 129±4 GeV , in the case when the Yukawa couplings of the neutrinos are less than half that of the top quark at the GUT scale.

scholarly journals A new angle on an old problem: helicity approach to neutron beta decay in the Standard Model

2019 ◽  
Vol 79 (11) ◽  
Author(s):  
Stefan Groote ◽  
Jürgen G. Körner ◽  
Blaženka Melić
Keyword(s):  
Axial Vector ◽  
Form Factors ◽  
Semileptonic Decays ◽  
The Other ◽  
Vector Form ◽  
Neutron Beta Decay ◽  
Heavy Baryons ◽  
The Standard Model ◽  
The One ◽  
Three Body

AbstractWe elaborate on the dichotomy between the description of the semileptonic decays of heavy hadrons on the one hand and the semileptonic decays of light hadrons such as neutron $$\beta $$β decays on the other hand. For example, almost without exception the semileptonic decays of heavy baryons are described in cascade fashion as a sequence of two two-body decays $$B_1 \rightarrow B_2 + W_\mathrm{off-shell}$$B1→B2+Woff-shell and $$W_{\mathrm{off-shell}} \rightarrow \ell + \nu _\ell $$Woff-shell→ℓ+νℓ whereas neutron $$\beta $$β decays are analyzed as true three-body decays $$n \rightarrow p + e^- +{\bar{\nu }}_e$$n→p+e-+ν¯e. Within the cascade approach it is possible to define a set of seven angular observables for polarized neutron $$\beta $$β decays as well as the longitudinal, transverse and normal polarization of the decay electron. We determine the dependence of the observables on the usual vector and axial vector form factors. In order to be able to assess the importance of recoil corrections we expand the rate and the $$q^2$$q2 averages of the observables up to NLO and NNLO in the recoil parameter $$\delta =(M_n-M_p)/(M_n+M_p)= 0.689\cdot 10^{-3}$$δ=(Mn-Mp)/(Mn+Mp)=0.689·10-3. Remarkably, we find that the rate and three of the four parity conserving polarization observables that we analyze are protected from NLO recoil corrections when the second class current contributions are set to zero.

scholarly journals On the Second Dipole Moment of Dirac’s Particle

2021 ◽  
Author(s):  
Engel Roza
Keyword(s):  
Dipole Moment ◽  
Electric Dipole Moment ◽  
Electric Dipole ◽  
Particle Physics ◽  
Critical Survey ◽  
Majorana Particle ◽  
Nuclear Domain ◽  
The Standard Model ◽  
Charge Parity ◽  
The One

An analysis is presented of the possible existence of a second anomalous dipole moment of Dirac&rsquo;s particle next to the one associated with the angular momentum. It includes a discussion why, in spite of his own derivation, Dirac has doubted about its relevancy. It is shown why since then it has been overlooked and why it has vanished from leading textbooks. A critical survey is given on the reasons of its reject, including the failure of attempts to measure and the perceived violations of time reversal symmetry and charge-parity symmetry. It is emphasized that the anomalous electric dipole moment of the pointlike electron (AEDM) is fundamentally different from the quantum field type electric dipole moment of an electron (eEDM) as defined in the standard model of particle physics. The analysis has resulted into the identification of a third type Dirac particle, next to the electron type and the Majorana particle. It is shown that, unlike as in the case of the electron type, its second anomalous dipole moment is real valued and is therefore subject to polarization in a vector field. Examples are given that it may have a possible impact in the nuclear domain and in the gravitational domain.

scholarly journals The determination of the angles between covalencies, from measurements of electric dipole moment

1933 ◽  
Vol 140 (842) ◽  
pp. 562-579 ◽  
Keyword(s):  
Dipole Moment ◽  
Electric Dipole Moment ◽  
Experimental Work ◽  
Electric Dipole ◽  
Dipole Moments ◽  
Present Communication ◽  
Electric Dipole Moments ◽  
The Subject ◽  
The One

Of the methods which have been devised for the measurement of angles between covalencies, the one based on measurements of electric dipole moments is among the most valuable. Descriptions of considerable experimental work on the subject have been published by several authors, but the discussions of the basis of the method, its further possible applications, the possible errors and their probable importance, are not only scattered, but incomplete. It therefore appeared desirable that a more complete, general treatment of these matters should be given, and the present communication is an attempt to do this.

scholarly journals CHARGED LEPTON ELECTRIC DIPOLE MOMENT ENHANCEMENT IN THE LORENTZ VIOLATED EXTENSION OF THE STANDARD MODEL

2013 ◽  
Vol 28 (24) ◽  
pp. 1350115 ◽  
Author(s):  
M. HAGHIGHAT ◽  
I. MOTIE ◽  
Z. REZAEI
Keyword(s):  
Dipole Moment ◽  
Standard Model ◽  
Momentum Transfer ◽  
Electric Dipole Moment ◽  
Electric Dipole ◽  
Charged Lepton ◽  
Form Factors ◽  
High Energy ◽  
Dipole Form Factor ◽  
The Standard Model

We consider the Lorentz violated extension of the standard model. In this framework, there are terms that explicitly violate CP-symmetry. We examine the CPT-even dμν-term to find the electric dipole moment of charged leptons. We show that the form factors besides the momentum transfer, depend on a new Lorentz-scalar, constructing by dμν and the four momenta of the lepton, as well. Such an energy dependence of the electric dipole form factor leads to an enhancement of the lepton electric dipole moment at high energy, even at the zero momentum transfer. We show that at [Formula: see text] the electric dipole moment of the charged lepton can be as large as 10-14 e cm .

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