Milena Piotrowska (Jan Kochanowski University, Kielce): Testing the quark-antiquark picture in the light meson sector

Monday 5 Feb 2018, 11:00 → 13:00 Europe/Budapest

Tanacsterem

We study mesonic resonances in the framework of the quark-antiquark
picture and beyond. In the first part of the talk, we investigate
the well-known ground-state vector meson $K^{\ast }(892)$ and two
scalar resonances, the broad and well established $K_0^{\ast }(1430)$ and
the not-yet confirmed $K_0^{\ast }(800)$. We show that the quark-antiquark
state $K^{\ast }(892)$ can be well described by a Breit-Wigner distribution with
a single pole on the complex plane, while $K_0^{\ast }(800)$  emerges as
a dynamically generated companion pole  of  the predominantly
quark-antiquark object $K_0^{\ast }(1430)$; in the scalar sector, the
whole spectral function has not a Breit-Wigner shape. The pole of
$K_0^{\ast }(800)$  is determined by a fit to data and evidence toward its
non-quark-antiquark nature is discussed.

In the second part, we study strong and radiative decays of two nonets
of excited vector mesons. These states can be in general quite well
understood as standard quark-antiquark objects. However, there is
still a state which escaped experimental verification:
the $s\overline{s}$ state in $1^3{D}_1$ nonet. We make predictions for the
mass and decays of this state, which can be searched in the GlueX and
CLAS12  experiments at Jefferson Lab.