scholarly journals CP violation in the lepton sector and implications for leptogenesis

2018 ◽  
Vol 33 (05n06) ◽  
pp. 1842006 ◽  
Author(s):  
C. Hagedorn ◽  
R. N. Mohapatra ◽  
E. Molinaro ◽  
C. C. Nishi ◽  
S. T. Petcov
Keyword(s):  
Cp Violation ◽  
Standard Model ◽  
Low Energy ◽  
Current Status ◽  
Neutrino Masses ◽  
Flavor Symmetry ◽  
Lepton Sector ◽  
The Standard Model ◽  
Mixing Matrix ◽  
Cp Symmetry

We review the current status of the data on neutrino masses and lepton mixing and the prospects for measuring the CP-violating phases in the lepton sector. The possible connection between low energy CP violation encoded in the Dirac and Majorana phases of the Pontecorvo–Maki–Nakagawa–Sakata mixing matrix and successful leptogenesis is emphasized in the context of seesaw extensions of the Standard Model with a flavor symmetry [Formula: see text] (and CP symmetry).

scholarly journals On the CP Violation Phase in a Neutrino Mixing Model with an A4 Flavor Symmetry

2016 ◽  
Vol 26 (1) ◽  
pp. 1
Author(s):  
Phi Quang Van ◽  
Nguyen Thi Hong Van
Keyword(s):  
Experimental Data ◽  
Cp Violation ◽  
Standard Model ◽  
Mixing Model ◽  
Neutrino Masses ◽  
Flavor Symmetry ◽  
Neutrino Mixing ◽  
Normal Ordering ◽  
Mixing Angles ◽  
Mixing Matrix

Neutrino masses and mixing in an extended standard model acquiring an A4 flavour symmetry are considered. The corresponding three-neutrino mixing matrix obtained via a pertur- bative method allows us to determine the Dirac CP violation phase (\delta_{CP}) as a function of the mixing angles (\theta_{12}, \theta_{23}, \theta_{13}). Then, numerical values and distributions of \delta_{CP} are given. The latter values are quite close to the global fits of the experimental data for both the normal ordering and inverse ordering of the neutrino masses.

scholarly journals From old symmetries to new symmetries: Quarks, leptons and B-L

2014 ◽  
Vol 29 (29) ◽  
pp. 1430066 ◽  
Author(s):  
Rabindra N. Mohapatra
Keyword(s):  
Standard Model ◽  
Weak Interactions ◽  
Low Energy ◽  
Neutrino Masses ◽  
Beyond The Standard Model ◽  
The Standard Model ◽  
Recent Developments

The Baryon–Lepton difference (B-L) is increasingly emerging as a possible new symmetry of the weak interactions of quarks and leptons as a way to understand the small neutrino masses. There is the possibility that current and future searches at colliders and in low energy rare processes may provide evidence for this symmetry. This paper provides a brief overview of the early developments that led to B-L as a possible symmetry beyond the standard model, and also discusses some recent developments.

scholarly journals Probing the nonunitarity of the leptonic mixing matrix at the CEPC

2016 ◽  
Vol 31 (33) ◽  
pp. 1644006 ◽  
Author(s):  
Stefan Antusch ◽  
Oliver Fischer
Keyword(s):  
Field Theory ◽  
Standard Model ◽  
Effective Field Theory ◽  
New Physics ◽  
Effective Field ◽  
Neutrino Masses ◽  
Performance Parameters ◽  
The Standard Model ◽  
Mixing Matrix ◽  
Theory Framework

The nonunitarity of the leptonic mixing matrix is a generic signal of new physics aiming at the generation of the observed neutrino masses. We discuss the Minimal Unitarity Violation (MUV) scheme, an effective field theory framework which represents the class of extensions of the Standard Model (SM) by heavy neutral leptons, and discuss the present bounds on the nonunitarity parameters as well as estimates for the sensitivity of the CEPC, based on the performance parameters from the preCDR.

scholarly journals RECENT DEVELOPMENTS IN PHYSICS BEYOND THE STANDARD MODEL

2000 ◽  
Vol 15 (supp01a) ◽  
pp. 440-463 ◽  
Author(s):  
GIAN F. GIUDICE
Keyword(s):  
Standard Model ◽  
Recent Work ◽  
Low Energy ◽  
Neutrino Masses ◽  
Beyond The Standard Model ◽  
The Standard Model ◽  
Spatial Dimensions ◽  
The Status ◽  
Recent Developments

In this talk I discuss what I believe are the most interesting recent developments in physics beyond the Standard Model. After some initial comments on neutrino masses, I discuss the status of low-energy supersymmetry and finally turn to describing some recent work in theories with extra spatial dimensions.

scholarly journals ON THE PHASE OF $B^0 - \bar B^0 $ MIXING MATRIX ELEMENT IN THE SUSY STANDARD MODEL

1995 ◽  
Vol 10 (22) ◽  
pp. 1577-1582 ◽  
Author(s):  
T. KURIMOTO
Keyword(s):  
Matrix Element ◽  
Cp Violation ◽  
Standard Model ◽  
Yukawa Coupling ◽  
Coupling Constants ◽  
Yukawa Interaction ◽  
Complex Phase ◽  
The Standard Model ◽  
Mixing Matrix ◽  
Minor Correction

It is shown that the complex phase of [Formula: see text] mixing matrix element is the same as that of the standard model up to the minor correction of the order of (mc/mt)2 or less in the SUSY standard model. This conclusion is valid as far as the Yukawa coupling constants are perturbative and realistic, and can be available for other realistic models where generation mixing and CP-violation are solely due to Yukawa interaction among quarks and Higgs doublets.

scholarly journals $K_{\rm L}\to \pi^0\nu\bar\nu$ AS A PROBE OF NEW PHYSICS

2006 ◽  
Vol 21 (03) ◽  
pp. 487-504 ◽  
Author(s):  
DOUGLAS BRYMAN ◽  
ANDRZEJ J. BURAS ◽  
GINO ISIDORI ◽  
LAURENCE LITTENBERG
Keyword(s):  
Cp Violation ◽  
Standard Model ◽  
Symmetry Breaking ◽  
New Physics ◽  
Flavor Symmetry ◽  
Beyond The Standard Model ◽  
Theoretical Virtues ◽  
Unique Role ◽  
The Standard Model

We summarize the theoretical virtues of the rare [Formula: see text] decays and emphasize the unique role of [Formula: see text] in probing the nature of physics beyond the Standard Model, in particular concerning possible new sources of CP violation and flavor-symmetry breaking. A brief summary of the prospects for the measurement of the [Formula: see text] rate is also given.

scholarly journals A new bound on CP violation in the τ lepton Yukawa coupling and electroweak baryogenesis

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
J. Alonso-González ◽  
L. Merlo ◽  
S. Pokorski
Keyword(s):  
Cp Violation ◽  
Standard Model ◽  
Yukawa Coupling ◽  
Effective Field ◽  
Beyond The Standard Model ◽  
Symmetry Violation ◽  
Yukawa Couplings ◽  
The Standard Model ◽  
Cp Symmetry ◽  
The Universe

Abstract The origin of the matter-antimatter asymmetry in the Universe is a fundamental question of physics. Electroweak baryogenesis is a compelling scenario for explaining it but it requires beyond the Standard Model sources of the CP symmetry violation. The simplest possibility is CP violation in the third generation fermion Higgs couplings, widely investigated theoretically and searched for experimentally. It has been found that the experimental bounds on the CP violation in the quark Yukawa couplings exclude their significant role in the electroweak baryogenesis, but it can be still played by the τ lepton Yukawa coupling. It is shown in this paper that, within the context of the Standard Model Effective Field Theory and assuming an underlying flavour symmetry of the Wilson coefficients, the electron dipole moment bound on the τ lepton Yukawa coupling is two orders of magnitude stronger than previously reported. This sheds strong doubts on its role in the electroweak baryogenesis, further stimulates the interest in its experimental verification and makes electroweak baryogenesis even more difficult to explain.

scholarly journals Electroweak-like baryogenesis with new chiral matter

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Kohei Fujikura ◽  
Keisuke Harigaya ◽  
Yuichiro Nakai ◽  
Ruoquan Wang
Keyword(s):  
Phase Transition ◽  
Gauge Symmetry ◽  
Cp Violation ◽  
Standard Model ◽  
Dipole Moments ◽  
Dark Matter Candidate ◽  
Lepton Asymmetry ◽  
First Order ◽  
The Standard Model ◽  
Concrete Realization

Abstract We propose a framework where a phase transition associated with a gauge symmetry breaking that occurs (not far) above the electroweak scale sets a stage for baryogenesis similar to the electroweak baryogenesis in the Standard Model. A concrete realization utilizes the breaking of SU(2)R× U(1)X→ U(1)Y. New chiral fermions charged under the extended gauge symmetry have nonzero lepton numbers, which makes the B − L symmetry anomalous. The new lepton sector contains a large flavor-dependent CP violation, similar to the Cabibbo-Kobayashi-Maskawa phase, without inducing sizable electric dipole moments of the Standard Model particles. A bubble wall dynamics associated with the first-order phase transition and SU(2)R sphaleron processes generate a lepton asymmetry, which is transferred into a baryon asymmetry via the ordinary electroweak sphaleron process. Unlike the Standard Model electroweak baryogenesis, the new phase transition can be of the strong first order and the new CP violation is not significantly suppressed by Yukawa couplings, so that the observed asymmetry can be produced. The model can be probed by collider searches for new particles and the observation of gravitational waves. One of the new leptons becomes a dark matter candidate. The model can be also embedded into a left-right symmetric theory to solve the strong CP problem.

scholarly journals Flavour Anomalies in a U(1) SUSY Extension of the SM

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 191
Author(s):  
Alexander Bednyakov ◽  
Alfiia Mukhaeva
Keyword(s):  
Standard Model ◽  
Parameter Space ◽  
Gauge Boson ◽  
New Physics ◽  
Low Energy ◽  
Effective Theory ◽  
The Standard Model ◽  
Meson Mixing ◽  
Additional Anomaly ◽  
Lepton Flavour

Flavour anomalies have attracted a lot of attention over recent years as they provide unique hints for possible New Physics. Here, we consider a supersymmetric (SUSY) extension of the Standard Model (SM) with an additional anomaly-free gauge U(1) group. The key feature of our model is the particular choice of non-universal charges to the gauge boson Z′, which not only allows a relaxation of the flavour discrepancies but, contrary to previous studies, can reproduce the SM mixing matrices both in the quark and lepton sectors. We pay special attention to the latter and explicitly enumerate all parameters relevant for our calculation in the low-energy effective theory. We find regions in the parameter space that satisfy experimental constraints on meson mixing and LHC Z′ searches and can alleviate the flavour anomalies. In addition, we also discuss the predictions for lepton-flavour violating decays B+→K+μτ and B+→K+eτ.

Sign in / Sign up

Export Citation Format

Share Document