Data-driven dispersive analysis of the $\pi \pi$ and $\pi K$ scattering

Autor: Danilkin, Igor, Deineka, Oleksandra, Vanderhaeghen, Marc
Rok vydání: 2020
Předmět:
Zdroj: Phys. Rev. D 103, 114023 (2021)
Druh dokumentu: Working Paper
DOI: 10.1103/PhysRevD.103.114023
Popis: 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 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.
Comment: 14 pages, 6 figures, the version accepted for publication in Physical Review D
Databáze: arXiv