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Related papers: Isospin breaking in Kl4 decays

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We discuss the isospin-breaking effects on threshold cusp structures in multichannel scattering near two-body thresholds. In hadronic systems with isospin symmetry, two or more nearly degenerate thresholds can appear, and their small…

High Energy Physics - Phenomenology · Physics 2026-05-27 Katsuyoshi Sone , Tetsuo Hyodo

We analyze isospin breaking through quark mass differences and virtual photons in the pion-nucleon scattering lengths in all physical channels in the framework of covariant baryon chiral perturbation theory. The so-called triangle relation…

High Energy Physics - Phenomenology · Physics 2014-11-20 Martin Hoferichter , Bastian Kubis , Ulf-G. Meißner

The final state interaction of pions in the decay $K^\pm\to \pi^+\pi^-e^\pm\nu$ allows to obtain the value of the isospin and angular momentum zero pion-pion scattering length $a_0^0$. To extract this quantity from experimental data the…

High Energy Physics - Phenomenology · Physics 2009-11-05 Yu. M. Bystritskiy , S. R. Gevorkyan , E. A. Kuraev

The master formula approach to chiral symmetry breaking is used to analyze the phase shifts for $\pi\pi$ scattering in the elastic region. The results are in excellent agreement with the data for the phase shifts up to the K-K bar…

High Energy Physics - Phenomenology · Physics 2009-10-28 James V. Steele , Hidenaga Yamagishi , Ismail Zahed

The $\tau^- \to \pi^-\eta\nu_{\tau}$ decay is forbidden in the Standard Model in the limit of exact $G$-parity, it becomes a rare decay due to isospin symmetry breaking and it is very sensitive to the effects of effective scalar…

High Energy Physics - Phenomenology · Physics 2024-02-08 Gerardo Hernández-Tomé , Gabriel López Castro , Diego Portillo-Sánchez

This Letter provides a new determination of the ten real coefficients that describe the structure of the $K \to \pi\pi\pi$ amplitudes in the limit where isospin is conserved and complex phases, due to either CP violation or final-state…

High Energy Physics - Phenomenology · Physics 2022-11-28 G. D'Ambrosio , M. Knecht , S. Neshatpour

We re-investigate the impact of isospin violation for extracting the s-wave pion pion scattering phase shift difference delta_0(M_K) - delta_2(M_K) from K -> pi pi decays. Compared to our previous analysis in 2003, more precise experimental…

High Energy Physics - Phenomenology · Physics 2009-09-28 V. Cirigliano , G. Ecker , A. Pich

We present a method to evaluate on the lattice the leading isospin breaking effects due to both the small mass difference between the up and down quarks and the QED interaction. Our proposal is applicable in principle to any QCD+QED gauge…

High Energy Physics - Lattice · Physics 2013-06-12 G. M. de Divitiis , R. Frezzotti , V. Lubicz , G. Martinelli , R. Petronzio , G. C. Rossi , F. Sanfilippo , S. Simula , N. Tantalo

On the basis of a next-to-leading-order calculation in chiral perturbation theory, the first complete analysis of isospin breaking for direct CP violation in K^0 -> 2 pi decays is performed. We find a destructive interference between three…

High Energy Physics - Phenomenology · Physics 2009-11-10 V. Cirigliano , A. Pich , G. Ecker , H. Neufeld

In the present paper we investigate the effect of symmetry breaking in the statistical distributions of reduced transition amplitudes and reduced transition probabilities. These quantities are easier to access experimentally than the…

Nuclear Theory · Physics 2009-10-31 C. I. Barbosa , T. Guhr , H. L. Harney

Although two pion decays of $K$, $D$ and $B$ have similar isospin structures, there are dramatic differences in the ratios $R_K$ and $R_{D,B}$ of amplitudes from $\Delta I =3/2$ and $\Delta I =1/2$ interactions. In $K\to \pi\pi$ decays…

High Energy Physics - Phenomenology · Physics 2009-11-10 Peng Guo , Xiao-Gang He , Xue-Qian Li

We complete here our work on isospin violation in the $K\to3\pi$ system. We first calculate $K\to2\pi$ to the same order as we did $K\to3\pi$ in papers I and II of this series. This adds effects of order $G_{27} p^2 (m_u-m_d)$ and $G_{27}…

High Energy Physics - Phenomenology · Physics 2011-09-13 Johan Bijnens , Fredrik Borg

A brief survey of applications of chiral perturbation theory to both semileptonic and nonleptonic kaon decays is presented. Special emphasis is given to recent theoretical advances related to semileptonic decays, in particular pion pion…

High Energy Physics - Phenomenology · Physics 2007-05-23 G. Ecker

The pion mass difference generates a pronounced cusp in the pi0 pi0 invariant mass distribution of K+ --> pi0 pi0 pi+ decays. As originally pointed out by Cabibbo, an accurate measurement of the cusp may allow one to pin down the S-wave…

High Energy Physics - Phenomenology · Physics 2014-11-20 Bastian Kubis

Recent work in low energy pion physics is reviewed. One of the exciting new developments in this field is that simulations of QCD on a lattice now start providing information about the low energy structure of the continuum theory, for…

High Energy Physics - Phenomenology · Physics 2017-08-23 H. Leutwyler

Complete next-to-leading (chiral) order (NLO) expressions for the strong isospin-breaking (IB) contributions in K -> pi pi are used to discuss (1) for CP-even, the impact on the magnitude of the Delta I=1/2 Rule, and (2) for CP-odd, the…

High Energy Physics - Phenomenology · Physics 2009-10-31 C. E. Wolfe , K. Maltman

Following Polchinski and Strassler [1] and our previous work [2], we study high-energy pion scattering in the holographic QCD hard-wall model. In particular, we focus on comparing our predictions for the angular dependence of $\pi^{+}…

High Energy Physics - Phenomenology · Physics 2026-04-08 Adi Armoni , Dorin Weissman

We perform a detailed study of the consequences of isospin symmetry in the Cabibbo favoured $D\to\Kbar\pi\pi$ decays. These processes are important for precision testing of the Standard Model and for hadronic physics. Combining isospin…

High Energy Physics - Phenomenology · Physics 2023-12-29 Emi Kou , Tetiana Moskalets , Bachir Moussallam

The available experimental information is consistent with the Weinberg predictions for the threshold parameters of pi-pi-scattering. The data, however, only test those relations that are insensitive to the quark masses m_u and m_d. Recent…

High Energy Physics - Phenomenology · Physics 2009-10-30 H. Leutwyler

Isospin-breaking effects, in particular those associated with electroweak-penguin contributions and pi0-eta,eta' mixing, have long been known to affect the Standard Model prediction of Re(epsilon'/epsilon) in a significant manner. We have…

High Energy Physics - Phenomenology · Physics 2011-02-01 S. Gardner
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