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In the standard model QCD Lagrangian, a term of CP violating gluon density is theoretically expected to have a physical coefficient $\bar{\theta}$ of the order of unity. However, the upper bound on the electric dipole moment of neutron…

高能物理 - 唯象学 · 物理学 2023-07-12 Pei-Hong Gu

CP invariance is a very attractive solution to the strong CP problem in QCD. This solution requires the vanishing ${\rm arg}\,[{\rm det}\, M_d\, {\rm det} M_u]$, where the $M_d$ and $M_u$ are the mass matrices for the down- and up-type…

高能物理 - 唯象学 · 物理学 2025-10-22 Morimitsu Tanimoto , Tsutomu T. Yanagida

In the vanilla type-I seesaw leptogenesis scenario, CP violation required to generate the lepton asymmetries in the heavy Majorana neutrino decays stem from complex Dirac-type Yukawa couplings. In this paper we explore the case in which…

高能物理 - 唯象学 · 物理学 2023-01-25 D. M. Barreiros , H. B. Câmara , R. G. Felipe , F. R. Joaquim

We examine the phase structure of a QCD-like theory at $\bar\theta =\pi$ obtained from supersymmetric $SU(N)$ QCD perturbed by a small amount of supersymmetry breaking via anomaly mediation (AMSB QCD). The spectrum of this theory matches…

高能物理 - 唯象学 · 物理学 2024-12-17 Csaba Csáki , Maximilian Ruhdorfer , Taewook Youn

We study the minimal version of the supersymmetric standard model with spontaneous CP breaking. In this model, the KM matrix is real and contributions to $\varepsilon$ arise from box diagrams involving squarks. We analyze the region of the…

高能物理 - 唯象学 · 物理学 2010-11-01 Alex Pomarol

We discuss a class of models in which CP is violated softly in a heavy sector adjoined to the standard model. Heavy-sector loops produce the observed CP violation in kaon physics, yielding a tiny and probably undetectable value for…

高能物理 - 唯象学 · 物理学 2009-09-11 Howard Georgi , Sheldon L. Glashow

A general analysis of possible violation of CP in processes like $\tau \to K\pi \nu$, for unpolarized $\tau$ is presented. In this paper, we derive the new contributions to the effective Hamiltonian governs $\vert\Delta S \vert=1$…

高能物理 - 唯象学 · 物理学 2021-04-28 David Delepine , Gaber Faisel , Carlos A. Ramirez

We construct phenomenologically viable supersymmetric models where CP is an approximate symmetry. The full high energy theory has exact CP and horizontal symmetries that are spontaneously broken with a naturally induced hierarchy of scales,…

高能物理 - 唯象学 · 物理学 2009-10-31 Galit Eyal , Yosef Nir

We present a unified relaxion solution to the five major outstanding issues in particle physics: the hierarchy problem, dark matter, matter-antimatter asymmetry, neutrino masses and the strong CP problem. The only additional field content…

高能物理 - 唯象学 · 物理学 2019-09-11 R. S. Gupta , J. Y. Reiness , M. Spannowsky

It is shown that if, from the starting point of a universal rank-one mass matrix long favoured by phenomenologists, one adds the assumption that it rotates (changes its orientation in generation space) with changing scale, one can…

高能物理 - 唯象学 · 物理学 2015-06-05 Michael J. Baker , J. Bordes , H. M. Chan , S. T. Tsou

Aiming at a model-independent analysis of possible new physics effects in semileptonic processes at various energy scales, we list and study a complete set of $SU(3)_c\times SU(2)_L\times U(1)_Y$ invariant 4-Fermi operators which consist of…

高能物理 - 唯象学 · 物理学 2007-05-23 We-Fu Chang , John N. Ng

In the electroweak sector of the Standard Model, CP violation arises through a very particular interplay between the three quark generations, as described by the Cabibbo--Kobayashi--Maskawa (CKM) mechanism and the single Jarlskog invariant…

高能物理 - 唯象学 · 物理学 2023-07-07 Quentin Bonnefoy , Emanuele Gendy , Christophe Grojean , Joshua T. Ruderman

The decay bar B -> bar K* (-> bar K pi) l+ l- offers great opportunities to explore the physics at and above the electroweak scale by means of an angular analysis. We investigate the physics potential of the seven CP asymmetries plus the…

高能物理 - 唯象学 · 物理学 2011-03-23 Christoph Bobeth , Gudrun Hiller , Giorgi Piranishvili

Scalar triplet extensions of the Standard Model provide an interesting playground for the explanation of neutrino mass suppression through the type-II seesaw mechanism. Propelled by the possible connections with leptonic CP violation, we…

高能物理 - 唯象学 · 物理学 2022-06-08 P. M. Ferreira , B. L. Gonçalves , F. R. Joaquim

We present a solution to the strong CP problem based on the identification of the theta angle with twice the CP violating phase present in the CKM quark matrix. This solution washes out all the unwanted issues stemming form the strong CP…

高能物理 - 唯象学 · 物理学 2018-02-23 Renata Jora

These lectures discuss the $\theta$ parameter of QCD. After an introduction to anomalies in four and two dimensions, the parameter is introduced. That such topological parameters can have physical effects is illustrated with two dimensional…

高能物理 - 唯象学 · 物理学 2007-05-23 Michael Dine

It is shown that in the scheme with a rotating fermion mass matrix (i.e. one with a scale-dependent orientation in generation space) suggested earlier for explaining fermion mixing and mass hierarchy, the theta-angle term in the QCD action…

高能物理 - 唯象学 · 物理学 2011-01-27 J. Bordes , H. M. Chan , S. T. Tsou

Recent improvements to the limit of Delta M_{B_s} imply that pure superweak theories, while not excluded, no longer provide a good fit to the data. A class of general superweak theories is introduced in which all flavor changing…

高能物理 - 唯象学 · 物理学 2009-10-30 Riccardo Barbieri , Lawrence Hall , Achille Stocchi , Neal Weiner

We propose simple scoto-seesaw models to account for dark matter and neutrino masses with spontaneous CP violation. This is achieved with a single horizontal $\mathcal{Z}_8$ discrete symmetry, broken to a residual $\mathcal{Z}_2$ subgroup…

高能物理 - 唯象学 · 物理学 2021-05-12 D. M. Barreiros , F. R. Joaquim , R. Srivastava , J. W. F. Valle

In the minimal left-right symmetric model, there are only two intrinsic CP violating phases to account for all CP violation in both the quark and lepton sectors, if CP is broken spontaneously by the complex phases in the VEV's of the scalar…

高能物理 - 唯象学 · 物理学 2009-11-10 Mu-Chun Chen , K. T. Mahanthappa