Related papers: Low Energy Pion-Hyperon Interaction
We study in various chiral models the pion charge radius, $\pi_{e3}$ form factor ratio, $\pi^\circ \to \gamma \gamma$ amplitude, charge pion polarizabilities, $\gamma\gamma \to \pi^\circ \pi^\circ$ amplitude at low energies and the $\pi\pi$…
The processes involving low energy $\bar{K}N$ and $Y\pi$ interactions (where $Y= \Sigma$ or $\Lambda$) are studied in the framework of heavy baryon chiral perturbation theory with the $\Lambda$(1405) resonance appearing as an independent…
Medium Effects in low-mass dilepton production in ultra-relativistic heavy-ion collisions are investigated using hadronic models. The rescattering of pions and rho mesons within a hot and dense hadron gas leads to substantial modifications…
We review two manifestations of chiral symmetry breaking in the pion sector. First, we examine the $\pi\pi$ scattering amplitude at threshold, which is completely determined by the chiral symmetry breaking part of the strong interaction,…
The dependence of K_{S,L}->\pi^{+}\pi^{-}\gamma decay probabilities on photon polarization is calculated. The phases of terms of amplitude that arise from the pion-pion interaction are obtained by using a simple realistic model of pion-pion…
We adopt the heavy baryon chiral perturbation theory to calculate the $\Sigma_cN$ interaction to the next-to-leading order. We consider the contact interactions, one-pion-exchange contributions, two-pion-exchange diagrams, and…
We define a family of non local and chirally symmetric low energy lagrangians motivated by theoretical studies on Quantum Chromodynamics. These models lead to quark propagators with non trivial momentum dependencies. We define the formalism…
We complete the recalculation of the available two-loop expressions for the reaction \gamma\gamma->\pi\pi in the framework of chiral perturbation theory. Here, we present the results for charged pions. The cross section and the values of…
We study the S-wave interaction of mesons with baryons in the strangeness S=0 sector in a coupled channel unitary approach. The basic dynamics is drawn from the lowest order meson baryon chiral Lagrangians. Small modifications inspired by…
A historical review of pion-nucleon interactions at low energy is presented, with aims toward an introductory, pedagogic approach focusing on issues germane to current research. These topics include the use of chiral effective field theory,…
We consider pion interactions in an effective field theory of the narrow resonance X(3872), assuming it is a weakly bound molecule of the charm mesons D^{0} \bar D^{*0} and D^{*0} \bar D^{0}. Since the hyperfine splitting of the D^{0} and…
The s-wave meson-nucleon interaction in the $S = -1$ sector is studied by means of coupled-channel Lippmann Schwinger equations, using the lowest order chiral Lagrangian and a cut off to regularize the loop integrals. The method reproduces…
This report describes the transitions pion -> meson_1 + meson_2 and also pion -> multi-pion for high energy pions interacting with target nuclei (Z,A). The physics interests are: A) Nuclear inelastic coherent diffraction cross sections for…
The low energy dynamics of the general strongly interacting symmetry breaking sector can be easily described using effective chiral Lagrangians. Indeed, the enhancement in WW scattering at LHC, that would imply the existence of such an…
The non-leptonic hyperon decays are analyzed up to one-loop order including all counterterms in the framework of heavy baryon chiral perturbation theory. We use the exchange of the spin-3/2 decuplet resonances as an indication of which…
We examine the hadronic interactions of quarkonia, focusing on the decays psi(2s)->psi pi pi and upsilon(2s)-> upsilon pi pi. The leading gluonic operators in the multipole expansion are matched onto the chiral lagrangian with the…
Precision studies at electron-positron colliders with center-of-mass energies in the charm-tau region and below have strongly contributed to our understanding of light-meson interactions at low energies. We focus on the processes involving…
We study CP violation and the contribution of the strong pion-pion interactions in the three-body B+- --> pi+- pi-+ pi+- decays within a quasi two-body QCD factorization approach. The short distance interaction amplitude is calculated in…
The interactions of $\rho$, $K^*$, $\phi$ and $\omega$ vector-mesons with low-momentum $\pi$, $K$ and $\eta$ pseudoscalar mesons are constrained by chiral symmetry. We derive a heavy vector-meson chiral Lagrangian in which the vector mesons…
The chiral two-pion exchange component of the long-range pp interaction is studied in an energy-dependent partial-wave analysis. We demonstrate its presence and importance, and determine the chiral parameters c_i (i=1,3,4). The values agree…