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CP violation due to interference between $K_L$ and $K_S$ decays into $\pi ^+\pi^-\gamma$ is analyzed in the Standard Model. The CP-violating parameter $\epsilon'_{+- \gamma}$, which is the difference between $\eta_{+-\gamma}$ and…

High Energy Physics - Phenomenology · Physics 2010-11-01 Hai-Yang Cheng

Starting from the time evolution of the C-odd $\bar{K}^0 K^0$ system, we analyze the asymmetries measurable at DAFNE and their implications on CP violation and on the possible tests of T and CPT symmetries. In particular the ratio…

High Energy Physics - Phenomenology · Physics 2008-02-03 G. D'Ambrosio , G. Isidori , A. Pugliese

Direct CP violation in the hadronic charm decays provides a good testing ground for the Kobayashi-Maskawa mechanism in the Standard Model. Any significant deviations from the expectation would be indirect evidence of physics beyond the…

High Energy Physics - Phenomenology · Physics 2019-11-20 Hai-Yang Cheng , Cheng-Wei Chiang

In this study the CP-asymmetry in the b \to s \ell^{+} \ell^{-} transition was investigated in minimal extension of the Standard Model where C_{9}^{eff} receives an extra weak phase due to the new physics effects. We observed that…

High Energy Physics - Phenomenology · Physics 2009-11-11 V. Bashiry

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,…

High Energy Physics - Phenomenology · Physics 2009-10-31 Galit Eyal , Yosef Nir

We present improved methods for calculating confidence intervals and $p$-values in situations where standard asymptotic approaches fail due to small sample sizes. We apply these techniques to a specific class of statistical model that can…

Data Analysis, Statistics and Probability · Physics 2024-01-11 Enzo Canonero , Alessandra Rosalba Brazzale , Glen Cowan

We argue that the observation of a sizable direct CP asymmetry A_{CP} in the inclusive decays B -> X_s gamma would be a clean signal of New Physics. In the Standard Model, A_{CP} can be calculated reliably and is found to be below 1% in…

High Energy Physics - Phenomenology · Physics 2016-08-25 A. L. Kagan , M. Neubert

In recent years, lattice determinations of non-perturbative quantities such as $f_K$ and $f_\pi$, which are relevant for $V_{us}$ and $V_{ud}$, have reached an impressive precision of $\mathcal{O}(1\%)$ or better. To make further progress,…

We present a study of the isospin-breaking (IB) corrections to pseudoscalar (PS) meson masses using the gauge configurations produced by the ETM Collaboration with $N_f=2+1+1$ dynamical quarks at three lattice spacings varying from 0.089 to…

High Energy Physics - Lattice · Physics 2018-04-18 D. Giusti , V. Lubicz , G. Martinelli , F. Sanfilippo , S. Simula , N. Tantalo , C. Tarantino

The observation of a sizable direct CP asymmetry in the inclusive decays B -> X_s 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 2007-05-23 Matthias Neubert

The NA48 experiment at CERN has performed a new measurement of direct CP violation, based on data taken in 1997 by simultaneously collecting K_L and K_S decays into pi0pi0 and pi+pi-. The result for the CP violating parameter…

High Energy Physics - Experiment · Physics 2008-11-26 The NA48 Collaboration , V. Fanti

We study the possibilities of spontaneous CP violation in the Next-to-Minimal Supersymmetric Standard Model with an extra singlet tadpole term in the scalar potential. We calculate the Higgs boson masses and couplings with radiative…

High Energy Physics - Phenomenology · Physics 2009-11-10 Cyril Hugonie , Jorge C. Romao , Ana M. Teixeira

Using large scale real-time lattice simulations, we calculate the baryon asymmetry generated at a fast, cold electroweak symmetry breaking transition. CP-violation is provided by the leading effective bosonic term resulting from integrating…

High Energy Physics - Phenomenology · Physics 2013-05-29 Anders Tranberg

We propose a simple renormalizable model for the spontaneous CP violation based on $SU(2)_{L}\times U(1)_{Y}\times A_{4}$ symmetry in a radiative seesaw mechanism, which can be guaranteed by an extra $Z_{2}$ symmetry. In our model CP is…

High Energy Physics - Phenomenology · Physics 2013-07-17 Y. H. Ahn , Sin Kyu Kang , C. S. Kim

Loop corrections for physics beyond the Standard Model are computed. DWe discuss the influence of new physics on CP-violating observables. Assuming the standard model gives a correct description of tree level processes, we show how a…

High Energy Physics - Phenomenology · Physics 2007-05-23 Daniel Wyler

The aim of this CP symmetry test in positronium is to measure the CP violation amplitude parameter \ccp. This is derived from the measurement of the asymmetry in an angular distribution of the photons from the decay of the ortho-positronium…

High Energy Physics - Experiment · Physics 2009-11-10 Marta Felcini

The recently observed direct CP violation in $B_d \to K^+ \pi^-$ has raised suggestions of possible new physics. A robust test of the standard model vs. new physics is its prediction of equal direct CP violation in $B_s \to K^- \pi^+$…

High Energy Physics - Phenomenology · Physics 2010-04-05 Harry J. Lipkin

The $\cp$ violating asymmetry $A(\Lambda^0_-)$ has been estimated to occur at the level of a few times $10^{-5}$ within the minimal standard model. The experiment E871 expects to reach a sensitivity of $10^{-4}$ to the asymmetry…

High Energy Physics - Phenomenology · Physics 2009-10-28 Xiao-Gang He , G. Valencia

The measurement of epsilon'/epsilon has left open several theoretical problems, the most important of which is an accurate calculation of the relevant hadronic matrix elements. Here we study the possibility of relating epsilon' to CP…

High Energy Physics - Phenomenology · Physics 2007-05-23 I. Scimemi , E. Gamiz , J. Prades

We present our preliminary results for the $\Delta I = 1/2$ matrix elements of $K\to\pi\pi$ decay and $\varepsilon'$, the measure of direct $CP$ violation in $K\to\pi\pi$, computed on multiple ensembles with periodic boundary conditions…

High Energy Physics - Lattice · Physics 2025-01-31 Masaaki Tomii