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The origin of the matter-antimatter asymmetry of the universe is one of the major unsolved problems in cosmology and particle physics. In this paper, we investigate the recently proposed possibility that split fermion models -- extra…

High Energy Physics - Phenomenology · Physics 2009-11-11 Andrew Coulthurst

CP-violating asymmetries in the processes e+e- -> t tbar and gamma gamma -> ttbar can provide information about CP-violating couplings of the top quark, whose presence would signal physics beyond the standard model. Work on studies of…

High Energy Physics - Phenomenology · Physics 2007-05-23 Saurabh D. Rindani

We discuss the question of CP-violation in the effective Hamiltonian approach in models of leptogenesis through heavy right handed neutrino decays. We first formulate the problem in four component notation and then point out that before the…

High Energy Physics - Phenomenology · Physics 2009-10-31 Utpal Sarkar , R. Vaidya

We study the generation of the matter-antimatter asymmetry during bosonic preheating, focusing on the sources of the asymmetry. If the asymmetry appears in the multiplication factor of the resonant particle production, the matter-antimatter…

High Energy Physics - Phenomenology · Physics 2018-09-26 Seishi Enomoto , Tomohiro Matsuda

Supersymmetric models with broken R-parity induced by lepton number violating terms provide a calculable framework for neutrino masses and mixings. Within models with bilinear R-parity breaking six new physical phases appear which are…

High Energy Physics - Phenomenology · Physics 2009-11-07 M. Hirsch , T. Kernreiter , W. Porod

We study the CP asymmetries of the rare top-quark decays $t \to c \gamma$ and $t \to cg$ in the aligned two-Higgs-doublet model (A2HDM), which is generically characterized by new sources of CP violation beyond the Standard Model (SM).…

High Energy Physics - Phenomenology · Physics 2025-03-17 Fang-Min Cai , Rui-Lin Fan , Xin-Qiang Li , Ya-Dong Yang

The Standard Model contains a natural source for CP asymmetries in weak decays, which is described by the KM mechanism. Beyond $\epsilon _K$ it generates only elusive manifestations of CP violation in {\em light-}quark systems. On the other…

High Energy Physics - Phenomenology · Physics 2009-09-25 I. I. Bigi

This work investigates the influence of directional properties of decoherence on kinetics rate equations. The physical reality is understood as a chain of unitary and decoherence events. The former are quantum-deterministic, while the…

Quantum Physics · Physics 2017-07-03 A. Y. Klimenko

There are numerous examples of approximately degenerate states of opposite parity in molecular physics. Theory indicates that these doubles can occur in molecules that are reflection-asymmetric. Such parity doubles occur in nuclear physics…

High Energy Physics - Theory · Physics 2009-10-30 A. P. Balachandran , S. Vaidya

We study four different models for CP violation: the standard (KM) model, the aspon model of spontaneous breaking and two models of soft breaking. In all except the standard model, the strong CP problem is addressed and solved. Testable…

High Energy Physics - Phenomenology · Physics 2014-11-17 Paul H. Frampton , Masayasu Harada

The article describes Boltzmann equations for a potential case of multi-particle dark matter with symmetric and asymmetric dark matter components in a model-independent approach. We focus on the specific scenario where one of the DM…

High Energy Physics - Phenomenology · Physics 2024-08-06 Amit Dutta Banik

Matter-antimatter asymmetries observed in high energy / relativistic heavy ion collisions and, differently, in the Early Universe are discussed considering ideas from the phase diagram of strong interactions with assumptions that do not…

High Energy Physics - Phenomenology · Physics 2025-02-25 Fabio L. Braghin

The matter-antimatter asymmetry problem, corresponding to the virtual nonexistence of antimatter in the universe, is one of the greatest mysteries of cosmology. Within the framework of the Generation Model (GM) of particle physics, it is…

General Physics · Physics 2016-09-15 B. A. Robson

We study CP asymmetries in lepton-number violating two-body scattering processes and show how they are related to CP asymmetries in the decays of intermediate massive Majorana neutrinos. Self-energy corrections, which do not contribute to…

High Energy Physics - Phenomenology · Physics 2009-10-30 W. Buchmuller , M. Plumacher

Leptogenesis is usually realized through decays of heavy particles. In this article we consider another possibility of generating a lepton asymmetry through annihilations of heavy particles. We demonstrate our idea with a realistic…

High Energy Physics - Phenomenology · Physics 2009-10-16 Pei-Hong Gu , Utpal Sarkar

Supersymmetric extensions to the standard model provide viable dark matter candidates, and can introduce additional charge-parity (CP) violation, needed for obtaining the observed baryon asymmetry of the universe. We study the possibilities…

High Energy Physics - Phenomenology · Physics 2013-04-09 Katri Huitu , Jari Laamanen , Lasse Leinonen , Santosh Kumar Rai , Timo Rüppell

The observation of a sizable CP asymmetry in the inclusive decays B -> Xs gamma would be a clean signal of New Physics. In the Standard Model, this asymmetry is below 1 % in magnitude. In extensions of the Standard Model with new…

High Energy Physics - Phenomenology · Physics 2009-10-31 Matthias Neubert

This two-part article considers certain fundamental symmetries of nature, namely the discrete symmetries of parity (P), charge conjugation (C) and time reversal (T), and their possible violation. Recent experimental results are discussed in…

Popular Physics · Physics 2007-05-23 B. Ananthanarayan , J. Meeraa , Bharti Sharma , Seema Sharma , Ritesh K. Singh

We consider a class of leptogenesis models in which the lepton asymmetry arises from dark matter annihilation processes which violate CP and lepton number. Importantly, a necessary one-loop contribution to the annihilation matrix element…

High Energy Physics - Phenomenology · Physics 2014-03-26 Jason Kumar , Patrick Stengel

Pair annihilation of heavy stable particle that occurs in the early universe is investigated, and quantum kinetic equation for the momentum distribution of the annihilating particle is derived, using the influence functional method. A…

High Energy Physics - Phenomenology · Physics 2009-10-31 Sh. Matsumoto , M. Yoshimura