Related papers: pi pi Phase shifts from K to 2 pi

We consider the quadratic scalar radius of the pion, $<r^2_{{\rm S},\pi}>$, and the mixed $K-\pi$ scalar radius, $<r^2_{{\rm S},K\pi}>$. With respect to the second, we point out that the more recent (post-1974) experimental results in…

We investigate the $a_0(980)$ resonance within chiral effective field theory through a three-coupled-channel analysis, namely $\pi\eta$, $K\bar{K}$ and $\pi\eta'$. A global fit to recent lattice finite-volume energy levels from $\pi\eta$…

Using data from FOCUS (E831) experiment at Fermilab, we present a model independent partial-wave analysis of the $K^-\pi^+$ S-wave amplitude from the decay $D^+ \to K^-\pi^+\pi^+$. The S-wave is a generic complex function to be determined…

We present for the first time a determination of the energy dependence of the isoscalar $\pi\pi$ elastic scattering phase-shift within a first-principles numerical lattice approach to QCD. Hadronic correlation functions are computed…

Recently we have shown an evidence for existence of \sigma-particle in the previous works; where the \pi\pi S-wave phase shift is reanalyzed, by introducing a repulsive background suggested by the chiral symmetry, and by applying a new…

A dynamical model for S-- and P--wave correlated $2 \pi$ (and $K \bar K$) exchange between a kaon and a nucleon is presented, starting from corresponding $N \bar N \rightarrow K \bar K$ amplitudes in the pseudophysical region, which have…

We investigate the $D_{s}^{+} \rightarrow K^{+} K^{-} \pi^{+}$ decay theoretically with the final state interactions, which is based on the chiral unitary approach and takes into account the external and internal $W$-emission mechanisms at…

An analysis of electromagnetic corrections to the (dominant) octet K -> pi pi hamiltonian using chiral perturbation theory is carried out. Relative shifts in amplitudes at the several per cent level are found.

I briefly review the current status of chiral perturbation theory in the meson sector. Emphasis is given on the quest for higher precision. I discuss two examples: one where it is difficult to make a good prediction (K_L -> pi^0 gamma…

We have studied the Cabibbo-suppressed decay mode D^0 into K^+ K^- pi^0 using a Dalitz plot technique and find the strong phase difference delta_D [defined as delta_(K*^- K^+) - delta_(K*^+ K^-)] = 332 degrees +- 8 degrees +- 11 degrees and…

We study I=0 $d$ wave $\pi\pi$ scattering phase shift using a proper unitarization approach. It is verified that the $f_2(1270)$ resonance corresponds to a twin pole structure: one on the second sheet, another one on the third sheet. Also…

The $\eta \to \pi^+ \pi^- \pi^0 \gamma$ decay is discussed in the general context of Chiral Perturbation Theory (ChPT), assuming that the low--energy constants (counter--terms) are saturated by vector-meson resonances. The $\eta \to \pi^+…

The $\pi\pi$ scattering amplitude with regular analytical properties in the $s$ complex plane has been constructed. It describes simultaneously the data on the $\pi\pi$ scattering, $\phi\to\pi^0\pi^0\gamma$ decay and $\pi\pi\to K\bar K$…

We study the long-distance dominated K_L -> pi^+ pi^- gamma decay at O(p^6) in Chiral Perturbation Theory. The complete calculation of the O(p^6) loop magnetic amplitude is carried out. At this chiral order the model dependent part of the…

The phase variation of the sigma -> pi-pi amplitude is accurately determined as a function of mass from BES II data for J/Psi -> omega-pi-pi. The determination arises from interference with the strong b1(1235)-pi amplitude. The observed…

Pion-kaon ($\pi K$) pairs occur frequently as final states in heavy-particle decays. A consistent treatment of $\pi K$ scattering and production amplitudes over a wide energy range is therefore mandatory for multiple applications: in…

The total cross section for the pp --> pp $\pi^0$ reaction at energies close to threshold is calculated within the frame of a chiral perturbation theory. The tree and one loop diagrams up to chiral order D=2 contributions are taken into…

From a re-analysis of pi+ pi- -> pi+ pi- and pi+ pi- -> K K data, we found for pi-pi S-wave interaction below 2 GeV, sigma(400), f0(980), f0(1500) and f0(1780) clearly show up. f0(1370) can be included with a very small branching ratio to…

We analyze $K \to \pi\pi\gamma$ decays in the framework of Chiral Perturbation Theory. We study the different Dalitz plot distributions, trying to find regions where o($p^6$) contributions could be more easily detected. To fulfill this…

Heavy flavour decay to light hadrons is the key to understanding many aspects of the SM from CP violation to strong dynamics. It is often presumed in line with the simple quark spectator model of D decay to Kpipi that the Kpi system has…