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Three possible strategies have been advocated to solve the strong CP problem. The first is the axion, a dynamical mechanism that relaxes any initial value of the CP violating angle $\bar{\theta}$ to zero. The second is the imposition of new…

High Energy Physics - Phenomenology · Physics 2025-05-14 David E. Kaplan , Tom Melia , Surjeet Rajendran

The radiative decay of neutral fermions has been studied for decades but $CP$ violation induced within such a paradigm has evaded attention. $CP$ violation in these processes can produce an asymmetry between circularly polarised directions…

High Energy Physics - Phenomenology · Physics 2020-04-28 Shyam Balaji , Maura Ramirez-Quezada , Ye-Ling Zhou

The non-perturbative implications of BRST quantization are examined for $\theta$ vacua and related issues. Strong CP violation is shown to be absent for QCD in the BRST formalism. Previous evidence for CP violation is reexamined, and much…

High Energy Physics - Phenomenology · Physics 2007-05-23 Hidenaga Yamagishi , Ismail Zahed

If CP violation in the decays of neutral kaons is due to phases in the weak couplings of quarks, as encoded in the Cabibbo-Kobayashi-Maskawa (CKM) matrix, there are many other experimental consequences. Notable among these are CP-violating…

High Energy Physics - Phenomenology · Physics 2009-09-25 J. Rosner

It is pointed out that the strong CP problem may have a natural solution in the context of a recently proposed dualized version of the Standard Model where Higgs fields and generations emerge naturally. Although fermions have finite…

High Energy Physics - Theory · Physics 2007-05-23 Jakov Pfaudler

It is shown that when the mass matrix changes in orientation (rotates) in generation space for changing energy scale, then the masses of the lower generations are not given just by its eigenvalues. In particular, these masses need not be…

High Energy Physics - Phenomenology · Physics 2009-02-09 Jose Bordes , H. M. Chan , S. T. Tsou

Assuming a new interaction with a $\theta$ term for the third generation of quarks, a value of $\theta$ different from zero dynamically induces the top- bottom mass splitting and a large CP-violating phase.

High Energy Physics - Phenomenology · Physics 2009-10-31 D. Delepine

We investigate the breakdown of Lorentz symmetry in QED by a CPT violating interaction term consisting of the coupling of an axial fermion current with a constant vector field $b$, in the framework of algebraic renormalization -- a…

High Energy Physics - Theory · Physics 2010-05-25 Oswaldo M. Del Cima , Jakson M. Fonseca , Daniel H. T. Franco , Olivier Piguet

In the framework of a renormalizable quantum field theory and taking the example of neutral kaons, CP violation is shown to be a dynamical consequence of the anomalous scaling of the fields; its connection to the mass splitting is…

High Energy Physics - Phenomenology · Physics 2007-05-23 B. Machet

We study a class of quark mass matrix models with the $\cal CP$-violating phase determined through making the $\cal CP$-violating parameter $J$ an extremum. These models assume that $m_u \ll m_c \ll m_t$ and that $m_d \ll m_s \ll m_b$. They…

High Energy Physics - Phenomenology · Physics 2007-05-23 B. Margolis , S. Punch , ; C. Hamzaoui

We calculate by the method of dimensional regularization and derivative expansion the one-loop effective action for a Dirac fermion with a Lorentz-violating and CPT-odd kinetic term in the background of a gauge field. We show that this term…

High Energy Physics - Theory · Physics 2009-10-31 J. -M. Chung , Phillial Oh

Studies of CP violation, for 30 years focused primarily on the neutral K meson, are on the threshold of a new era as experiments approach Standard-Model sensitivities in decays of beauty, charm, and hyperons. The array of heavy-quark…

High Energy Physics - Experiment · Physics 2008-02-03 Daniel M. Kaplan

We describe a method that is used to reduce, significantly, the number of CP violating complex phases in the Yukawa parameters. With this Reduction of Complex Phases (RCP) we obtain only one CP violating complex phase in the case where the…

High Energy Physics - Phenomenology · Physics 2007-05-23 J. I. Silva-Marcos

I discuss the suppression of the lightest generation fermion mass terms in realistic superstring standard--like models in the free fermionic formulation. The suppression of the mass terms is a consequence of horizontal symmetries that arise…

High Energy Physics - Phenomenology · Physics 2009-10-22 Alon E. Faraggi

The CP violation required in leptogenesis may have different origin, but in an effective theory they all are related to the rephasing invariant CP violating measure in the mixing matrix of the leptonic sector. We point out that the maximum…

High Energy Physics - Phenomenology · Physics 2011-09-16 Yong Liu , Utpal Sarkar

We discuss the notion of mass, mostly for fermions, and its relation to the breaking of CP invariance, the natural symmetry of gauge interactions. In a first model, we show how compactification on a Vortex in 2 extra dimensions leads to a…

High Energy Physics - Phenomenology · Physics 2009-09-29 J. -M. Frère

We analyse the general constraints on unified gauge models with spontaneous CP breaking that satisfy the conditions that (i) CP violation in the quark sector is described by a realistic complex CKM matrix, and (ii) there is no significant…

High Energy Physics - Phenomenology · Physics 2008-11-26 G. C. Branco , R. N. Mohapatra

CP violation in $B$ decays is reviewed in the Standard Model (SM) and beyond the SM. The present explanation of CP violation in terms of a phase in the Cabibbo-Kobayashi-Maskawa (CKM) matrix can be tested through a variety of CP asymmetries…

High Energy Physics - Phenomenology · Physics 2016-09-06 Michael Gronau

CP violation in K and B decays is reviewed in the Standard Model (SM) and beyond the SM. In K decays, one is seeking first evidence for CP violation in direct $K\to \pi\pi$ decays. This would not give a precise quantitative test for the…

High Energy Physics - Phenomenology · Physics 2014-11-17 Michael Gronau

We give an overview of recent progress in the study of fermion mass and flavor mixing phenomena. The hints exhibited by the quark and lepton mass spectra towards possible underlying flavor symmetries, from which realistic models of mass…

High Energy Physics - Phenomenology · Physics 2014-11-17 Harald Fritzsch , Zhi-zhong Xing