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Related papers: A Non-Perturbative Chiral Approach for Meson-Meson…

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The problem of scalar mesons still remains a challenging puzzle, for which we do not even know which are the right pieces to set up. The proliferation of resonances (some of them are very broad and appear on top of hadronic thresholds) and…

High Energy Physics - Phenomenology · Physics 2011-03-31 Miguel Albaladejo , Jose A. Oller , Cándido Piqueras

We analyse the extension of Chiral Perturbation Theory to describe a meson gas out of thermal equilibrium. For that purpose, we let the pion decay constant be a time-dependent function and work within the Schwinger-Keldysh contour…

High Energy Physics - Phenomenology · Physics 2016-09-06 A. Gomez Nicola

I review recent developments in chiral perturbation theory (CHPT) which is the effective field theory of the standard model below the chiral symmetry breaking scale. The effective chiral Lagrangian formulated in terms of the pseudoscalar…

High Energy Physics - Phenomenology · Physics 2010-12-17 Ulf-G. Meißner

We report on our recent work about the description of a meson gas below the chiral phase transition within the framework of Chiral Perturbation Theory. As an alternative to the standard treatment, we present a calculation of the quark…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. Gomez Nicola , J. R. Pelaez , A. Dobado , F. J. LLanes-Estrada

The most general structure of an elastic partial wave amplitude when the unphysical cuts are neglected is deduced in terms of the N/D method. This result is then matched to lowest order, ${\mathcal{O}}(p^2)$, Chiral Perturbation…

High Energy Physics - Phenomenology · Physics 2008-11-26 J. A. Oller , E. Oset

The $s-$wave meson-baryon scattering amplitude is analyzed for the strangeness $S=-1$ and isospin I=0 sector in a Bethe-Salpeter coupled channel formalism incorporating Chiral Symmetry. Four two-body channels have been considered: $\bar K…

Nuclear Theory · Physics 2016-08-16 C. Garcia-Recio , J. Nieves , E. Ruiz Arriola , M. Vicente Vacas

We present a chiral ${\bar K}N$ interaction model that has been developed and optimized in order to account for the experimental data of inelastic ${\bar K}N$ reaction channels that open at higher energies. In particular, we study the…

High Energy Physics - Phenomenology · Physics 2021-07-23 Albert Feijoo , Daniel Gazda , Volodymyr Magas , Angels Ramos

It has previously been demonstrated that the mesonic fields in chiral Lagrangians can be related to the quark-level operators of QCD sum-rules via energy-independent (constant) scale factor matrices constrained by chiral symmetry. This…

High Energy Physics - Phenomenology · Physics 2025-01-23 Amir H. Fariborz , J. Ho , T. G. Steele

We present a study of the $S=-1$ meson-baryon interaction, employing a chiral SU(3) Lagrangian up to next-to-leading order (NLO) and implementing unitarization in coupled channels. The parameters of the model have been fitted to a large set…

Nuclear Theory · Physics 2016-08-24 A. Ramos , A. Feijoo , V. K. Magas

The $SU(3)$ chiral effective lagrangian at next-to-leading order is applied to the S-wave meson-baryon interaction in the energy range around the $\eta N$ threshold. Potentials are derived from this lagrangian and used in a coupled channel…

Nuclear Theory · Physics 2009-10-28 N. Kaiser , P. B. Siegel , W. Weise

In these lectures I make an introduction to chiral unitary theory applied to the meson baryon interaction and show how several well known resonances are dynamically generated, and others are predicted. Two very recent experiments are…

Nuclear Theory · Physics 2011-02-09 E. Oset , D. Cabrera , V. K. Magas , L. Roca , S. Sarkar , M. J. Vicente Vacas , A. Ramos

Non--resonant decays of charmed mesons into three pseudoscalars are analyzed in a weak gauged $U(4)_L \otimes U(4)_R$ chiral lagrangian model. The calculation is free of unknown parameters and only requires the masses of pseudoscalar mesons…

High Energy Physics - Phenomenology · Physics 2009-10-28 F. J. Botella , S. Noguera , J. Portoles

We analize the most general low-energy effective lagrangian including local parity violating terms parametrized by an axial chemical potential $\mu_5$. This result is obtained following the external source method, up to $\mathcal{O}(p^4)$…

High Energy Physics - Phenomenology · Physics 2021-12-28 Andrea Vioque-Rodríguez , Angel Gómez Nicola , Domènec Espriu

We review two approaches to studying pseudoscalar meson-meson scattering amplitudes to beyond 1 GeV using non-linear and linear chiral Lagrangians. These approaches use two different unitarisation techniques - a generalised Breit Wigner…

High Energy Physics - Phenomenology · Physics 2008-01-17 Deirdre Black , Jonathan Gaunt

The talk contains a short introduction to mesonic Chiral Perturbation Theory (ChPT). In addition four disparate areas where some progress has been made in recent years are discussed. These are the last fit of the order $p^4$…

High Energy Physics - Phenomenology · Physics 2013-01-30 Johan Bijnens

A $1/\N$ expansion of the chiral Lagrangian for baryons is formulated and used to study the low-energy dynamics of baryons interacting with the pion nonet $\pi$, $K$, $\eta$ and $\eta^\prime$ in a combined expansion in chiral symmetry…

High Energy Physics - Phenomenology · Physics 2008-11-26 Elizabeth Jenkins

We calculate the threshold $T$ matrices of the meson and baryon processes that have no annihilation diagrams: $\pi^{+}\Sigma^{+}$, $\pi^{+}\Xi^0$, $K^+p$, $K^+n$, and $\bar{K}^0\Xi^0$ to the fourth order in heavy baryon chiral perturbation…

High Energy Physics - Phenomenology · Physics 2025-10-10 Jing Ou-Yang , Ke Wang , Bo-Lin Huang

We perform a non-perturbative chiral study of the masses of the lightest pseudoscalar mesons. In the calculation of the self-energies we employ the S-wave meson-meson amplitudes taken from Unitary Chiral Perturbation Theory (UCHPT) that…

High Energy Physics - Phenomenology · Physics 2009-09-29 Jose A. Oller , Luis Roca

Broken chiral symmetry has become the basis for a unified treatment of hadronic interactions at low energies. After reviewing mechanisms for spontaneous chiral symmetry breaking, I outline the construction of the low--energy effective field…

High Energy Physics - Phenomenology · Physics 2009-10-31 Gerhard Ecker

We calculate the effective potentials of the octet baryon and heavy meson systems using the chiral effective field theory up to the next-to-leading order. We consider the contact terms, one-pseudoscalar-meson and two-pseudoscalar-meson…

High Energy Physics - Phenomenology · Physics 2024-12-12 Bo-Lin Huang , Bo Wang , Shi-Lin Zhu