24-30 July 2016
Highfield Campus, University of Southampton
Europe/London timezone

An $a_0$ resonance in strongly coupled $\pi \eta$, $K \overline{K}$ scattering from lattice QCD

26 Jul 2016, 16:50
20m
Building B2a Room 2065 (Highfield Campus, University of Southampton)

Building B2a Room 2065

Highfield Campus, University of Southampton

Talk Hadron Spectroscopy and Interactions Hadron Spectroscopy and Interactions

Speaker

Jozef Dudek (Jefferson Lab)

Description

We present the first calculation of coupled-channel meson-meson scattering in the isospin $=1$, $G$-parity negative sector, with channels $\pi \eta$, $K\overline{K}$ and $\pi \eta'$, in a first-principles approach to QCD. From the discrete spectrum of eigenstates in three volumes extracted from lattice QCD correlation functions we determine the energy dependence of the $S$-matrix, and find that the $S$-wave features a prominent cusp-like structure in $\pi \eta \to \pi \eta$ close to $K\overline{K}$ threshold coupled with a rapid turn on of amplitudes leading to the $K\overline{K}$ final-state. This behavior is traced to an $a_0(980)$-like resonance, strongly coupled to both $\pi \eta$ and $K\overline{K}$, which is identified with a pole in the complex energy plane, appearing on only a single unphysical Riemann sheet. Consideration of $D$-wave scattering suggests a narrow tensor resonance at higher energy.

Primary author

Jozef Dudek (Jefferson Lab)

Presentation Materials