May 17 – 20, 2021
online via ZOOM
Europe/Warsaw timezone

Data-driven dispersive analysis of the $\pi \pi$ and $\pi K$ scattering for physical and unphysical pion masses

May 18, 2021, 1:00 PM
30m
online via ZOOM

online via ZOOM

Plenary Plenary Session

Speaker

Oleksandra Deineka (Johannes Gutenberg University Mainz)

Description

We present a data-driven analysis of the resonant S-wave $\pi\pi \to \pi\pi$ and $\pi K \to \pi K$ reactions using the partial-wave dispersion relation. The contributions from the left-hand cuts are accounted for in a model-independent way using the Taylor expansion in a suitably constructed conformal variable. The fits are performed to experimental and lattice data as well as Roy analyses. For the $\pi\pi$ scattering we present both a single- and coupled-channel analysis by including additionally the $K\bar{K}$ channel. For the latter the central result is the Omn`es matrix, which is consistent with the most recent Roy and Roy-Steiner results on $\pi\pi \to \pi\pi$ and $\pi\pi \to K\bar{K}$, respectively. By the analytic continuation to the complex plane, we found poles associated with the lightest scalar resonances $\sigma/f_0(500)$, $f_0(980)$, and $\kappa/K_0^*(700)$ for the physical pion mass value and in the case of $\sigma/f_0(500)$, $\kappa/K_0^*(700)$ also for unphysical pion mass values. The obtained Omn`es functions are used for the description of the double-virtual photon-photon scattering to two pions up to 1.5 GeV.

Primary authors

Oleksandra Deineka (Johannes Gutenberg University Mainz) Dr Igor Danilkin (Johannes Gutenberg University Mainz) Prof. Marc Vanderhaeghen (Johannes Gutenberg University Mainz)

Presentation materials