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We analyse the strength of CP violation in an extension of the standard model with an extra $Q=-1/3$ vector-like singlet quark, in the framework of the hypothesis of universality of strength of Yukawa couplings connecting standard quarks.…

High Energy Physics - Phenomenology · Physics 2013-07-02 G. C. Branco , H. R. Colaço Ferreira , A. G. Hessler , J. I. Silva-Marcos

We present a model for quark masses and mixing, featuring geometrical CP violation through a \Delta(27) triplet. By employing a single U(1)_F or Z_N symmetry in addition to \Delta(27), we forbid all terms in the scalar potential that would…

High Energy Physics - Phenomenology · Physics 2015-06-16 Ivo de Medeiros Varzielas , Daniel Pidt

It is shown that the so-called "Yukawaon" model can give a unified description of masses, mixing and $CP$ violation parameters of quarks and leptons without using any hierarchical (family number-dependent) parameters besides the charged…

High Energy Physics - Phenomenology · Physics 2015-10-22 Yoshio Koide , Hiroyuki Nishiura

Because 4-dimensional CP is a good symmetry of many higher-dimensional theories, this suggests the possible existence of a universal CP-violating phase originating from the process of compactification. Such a phase, if it existed, would not…

High Energy Physics - Phenomenology · Physics 2011-04-22 R. D. Peccei

We study the CP violation of universal seesaw model, especially its quark sector. The model is based on SU(2)_L \times SU(2)_R \times U(1)_{Y^\prime}. In order to count the number of parameters in quark sector, we use the degree of freedom…

High Energy Physics - Phenomenology · Physics 2015-06-16 Ryomu Kawasaki , Takuya Morozumi , Hiroyuki Umeeda

We develop for the CKM and PMNS matrices a new representation with special properties. It is obtained by splitting each of these matrices into two rotations by the angle ${\sim}2\pi/3$ and a universal diagonal matrix with elements, which…

High Energy Physics - Phenomenology · Physics 2024-01-31 Piotr Kielanowski , S. Rebeca Juárez Wysozka , Liliana Vázquez Mercado

We show that the quark flavour structure and CP violating phenomena are strongly correlated in supersymmetric theories. For a generic pattern of supersymmetry breaking the two broad categories of Yukawa couplings, democratic and…

High Energy Physics - Phenomenology · Physics 2014-11-17 S. Abel , G. C. Branco , S. Khalil

We analyse the CP problem in the context of a supersymmetric extension of the standard model with universal strength of Yukawa couplings. A salient feature of these models is that the CP phases are constrained to be very small by the…

High Energy Physics - Phenomenology · Physics 2009-09-25 G. C. Branco , M. E. Gomez , S. Khalil , A. M. Teixeira

We analyse a possible connection between CP violations in the quark and lepton sectors, parametrised by the CKM and PMNS phases. If one assumes that CP breaking arises from complex Yukawa couplings, both in the quark and lepton sectors, the…

High Energy Physics - Phenomenology · Physics 2021-09-01 João M. Alves , Francisco J. Botella , Gustavo C. Branco , Fernando Cornet-Gomez , Miguel Nebot

We present a two-Higgs-doublet model, with a $\mathbbm{Z}_3$ symmetry, in which CP violation originates solely in a soft (dimension-2) coupling in the scalar potential, and reveals itself solely in the CKM (quark mixing) matrix. In…

High Energy Physics - Phenomenology · Physics 2011-11-21 P. M. Ferreira , J. P. Silva , L. Lavoura

The CKM matrix describing quark mixing with three generations can be parameterized by three mixing angles and one CP violating phase. In most of the parameterizations, the CP violating phase chosen is not a directly measurable quantity and…

High Energy Physics - Phenomenology · Physics 2015-06-04 Guan-Nan Li , Hsiu-Hsien Lin , Dong Xu , Xiao-Gang He

A shape of the unitary triangle versus a CP violating parameter \delta depends on the phase conventions of the CKM matrix, because the CP violating parameter \delta cannot directly be observed, so that it is not rephasing-invariant. In…

High Energy Physics - Phenomenology · Physics 2014-11-18 Yoshio Koide

We assume the universal Yukawa coupling (democratic mass matrix) with small violations for quarks, charged leptons and neutrinos masses. We could reproduce the mass hierarchy for quark masses and V_{CKM} matrix elements precisely. We adopt…

High Energy Physics - Phenomenology · Physics 2009-10-31 T. Teshima , T. Asai

We propose a new mass matrix ansatz: At the grand unified (GU) scale, the standard model (SM) Yukawa coupling matrix elements are integer powers of the square root of the GU gauge coupling constant \varepsilon \equiv…

High Energy Physics - Phenomenology · Physics 2014-11-20 Yong-Chao Zhang , De-Hai Zhang

The maximal CP violation hypothesis depends on the phase convention of the Cabibbo-Kobayashi-Maskawa matrix. A phase convention which leads to successful prediction under the maximal CP violation hypothesis is searched, and thereby,…

High Energy Physics - Phenomenology · Physics 2014-11-18 Yoshio Koide

We analyse the CP problem in the context of a supersymmetric extension of the standard model with universal strength of Yukawa couplings. In these models we find a small amount of CP violation from the usual CKM mechanism and therefore a…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. M. Teixeira , G. C. Branco , M. E. Gomez , S. Khalil

Within a specific texture of the quark mass matrix the notion of a maximal violation of the $CP$ symmetry can be defined. The experimental constraints from weak decays imply that in reality one is close to the case of maximal $CP$…

High Energy Physics - Phenomenology · Physics 2010-11-01 Harald Fritzsch , Zhi-zong Xing

The latest experimental progress have established three kinds of neutrino oscillations with three mixing angles measured to rather high precision. There is still one parameter, i.e., the CP violating phase, missing in the neutrino mixing…

High Energy Physics - Phenomenology · Physics 2012-06-22 Xinyi Zhang , Bo-Qiang Ma

In Standard Model, CP violation arises from an irreducible complex phase in the quark mixing matrix, now under the name Cabibbo-Kobayashi-Maskawa matrix. This description has shown remarkably overall agreement with various experimental…

High Energy Physics - Phenomenology · Physics 2014-08-06 Wei Wang

A simple breaking of the subnuclear democracy among the quarks leads to a mixing between the second and the third family, in agreement with observation. Introducing the mixing between the first and the second family, one finds an…

High Energy Physics - Phenomenology · Physics 2007-05-23 Harald Fritzsch
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