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Related papers: Dispersive analysis of the decay eta -> 3 pi

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The decay $\eta \to 3 \pi$ proceeds exclusively through isospin violating operators and is therefore an excellent probe to examine the strength of isospin breaking in the strong interaction. The latter can be expressed through the quark…

High Energy Physics - Phenomenology · Physics 2018-09-27 Stefan Lanz

The $\eta \to 3 \pi$ amplitude is sensitive to the quark mass difference $m_u-m_d$ and offers a unique way to determine the quark mass ratio $Q^2 \equiv (m_s^2-m_{ud}^2)/(m_d^2-m_u^2)$ from experiment. We calculate the amplitude…

High Energy Physics - Phenomenology · Physics 2017-01-23 Gilberto Colangelo , Stefan Lanz , Heinrich Leutwyler , Emilie Passemar

The dispersive analysis of the decay $\eta\to3\pi$ is reviewed and thoroughly updated with the aim of determining the quark mass ratio ~$Q^2=(m_s^2-m_{ud}^2)/(m_d^2-m_u^2)$. With the number of subtractions we are using, the effects…

High Energy Physics - Phenomenology · Physics 2018-11-20 Gilberto Colangelo , Stefan Lanz , Heinrich Leutwyler , Emilie Passemar

We present a new dispersive analysis of the isospin breaking decay eta --> 3 pi. The resulting representation of the decay amplitude allows us to determine the quark mass double ratio Q and we find as a preliminary result Q = 22.3 +/- 0.4.…

High Energy Physics - Phenomenology · Physics 2014-11-20 Gilberto Colangelo , Stefan Lanz , Emilie Passemar

The branching ratio of the \eta->3\pi decay is an important source of information on the value of the quark mass ratio 1/R=(m_d-m_u)/(m_s-\hat m). Furthermore, isospin breaking effects in the decays K->3\pi provide information on the pion…

High Energy Physics - Phenomenology · Physics 2011-03-07 M. Zdrahal , K. Kampf , M. Knecht , J. Novotny

Because of their small electromagnetic corrections, the isospin-breaking decays $\eta\to3\pi$ seem to be good candidates for extracting isospin-breaking parameters $ (m_d-m_u)$. This task is unfortunately complicated by large chiral…

High Energy Physics - Phenomenology · Physics 2011-12-21 Karol Kampf , Marc Knecht , Jiří Novotný , Martin Zdráhal

In recent years, the decay eta --> 3 pi has received considerable attention from experimental and theoretical side. It is of particular theoretical interest because it allows for the determination of (m_u - m_d). In addition, for many years…

High Energy Physics - Phenomenology · Physics 2013-08-26 Stefan Lanz

For a precise determination of the m_u and m_d quark masses, it is useful to combine isospin symmetric results of lattice or sum rules QCD techniques with some isospin breaking study performed in chiral perturbation theory (ChPT). The most…

High Energy Physics - Phenomenology · Physics 2012-01-23 Martin Zdrahal

Taken by itself, the interference with the etaprime appears to strongly affect the amplitude of the transition eta->3 pi. I point out that this effect is fictitious and also occurs in the mass spectrum of the pseudoscalars. Chiral symmetry…

High Energy Physics - Phenomenology · Physics 2009-10-28 H. Leutwyler

We obtain explicit expressions for the \eta and \eta' masses and decay constants using U_L(3) x U_R(3) chiral perturbation theory at next-to-leading order in a combined expansion in p^2 and 1/Nc. A numerical fit of the parameters appearing…

High Energy Physics - Phenomenology · Physics 2009-10-30 P. Herrera-Siklódy , J. I. Latorre , P. Pascual , J. Taron

The branching fraction of the decay $\eta' \to \pi\rho$ is calculated in the chiral quark NJL model. The decay exists due to the mass difference between $u$- and $d$-quarks leading to $\pi^{0}-\eta^{'}$ mixing. Two different approaches are…

High Energy Physics - Phenomenology · Physics 2022-11-29 M. K. Volkov , A. A. Pivovarov , K. Nurlan

In the framework of Chiral Perturbation Theory including photons, we found that the contribution of the photon exchange between two intermediate charged Kaons to the slope parameter of the decay (\eta\rightarrow 3\pi^{0}) amounts to…

High Energy Physics - Phenomenology · Physics 2011-06-20 A. Nehme

The eta to 3 pion decays are a valuable source of information on low energy QCD. Yet they were not used for an extraction of the chiral symmetry breaking order parameters until now. We use a bayesian approach in the framework of resummed…

High Energy Physics - Phenomenology · Physics 2014-09-12 Marian Kolesar , Jiri Novotny

We investigate the $\eta^\prime \to \eta \pi\pi$ decays within the framework of large-$N_{C}$ chiral perturbation theory, by calculating the decay amplitudes up to next-to-next-to-leading order in a simultaneous expansion in powers of…

High Energy Physics - Phenomenology · Physics 2026-05-12 Feng-Zhi Chen , Xin-Qiang Li , Ya-Dong Yang , Yuan-He Zou

The claim that the light quark mass ratio (m_d - m_u)/m_s can be extracted from the decay width ratio Gamma(eta' -> pi^0 pi^+ pi^-)/Gamma(eta' -> eta pi^+ pi^-) is critically investigated within a U(3) chiral unitary framework. The…

High Energy Physics - Phenomenology · Physics 2008-11-26 B. Borasoy , Ulf-G. Meißner , R. Nißler

High statistics Dalitz-plot distribution of $\eta \to \pi^+\pi^-\pi^0$ decay obtained recently by KLOE collaboration \cite{kloe} is fitted to the results of corresponding theoretical calculations in Chiral Perturbation Theory (ChPT) with…

High Energy Physics - Phenomenology · Physics 2008-11-26 B. V. Martemyanov , V. S. Sopov

In this article, we study the decays $\psi^{\prime}\to {J/\psi}\pi^+\pi^-$ and $\eta_c^{\prime}\to {\eta_c}\pi^+\pi^-$ by taking into account the chiral symmetry breaking effects, the final-state interactions and the heavy quark symmetry.…

High Energy Physics - Phenomenology · Physics 2011-08-11 Zhi-Gang Wang

The isospin-breaking decay eta {\to} 3pi is an ideal tool to extract information on light quark mass ratios from experiment. For a precise determination, however, a detailed description of the Dalitz plot distribution is necessary. In that…

High Energy Physics - Phenomenology · Physics 2011-02-17 Sebastian P. Schneider , Bastian Kubis , Christoph Ditsche

We present an unitary dispersive model for the $\eta \to 3 \pi$ decay process based upon the Khuri-Treiman equations which are solved by means of the Pasquier inversion method. The description of the hadronic final-state interactions for…

High Energy Physics - Phenomenology · Physics 2016-08-08 Peng Guo , Igor V. Danilkin , Diane Schott , C. Fernández-Ramírez , V. Mathieu , Adam P. Szczepaniak

We calculate the decay $\eta\to3\pi$ at next-to-next-to-leading order or order $p^6$ in Chiral Perturbation Theory. The corrections are somewhat larger than was indicated by dispersive estimates. We present numerical results for the Dalitz…

High Energy Physics - Phenomenology · Physics 2009-01-06 Johan Bijnens , Karim Ghorbani
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