Denis Parganlija

Vacuum properties of mesons in a linear sigma model with vector mesons and global chiral invariance

We present a two-flavor linear sigma model with global chiral symmetry and vector and axial-vector mesons. We calculate {pi}{pi} scattering lengths and the decay widths of scalar, vector, and axial-vector mesons. It is demonstrated that vector and axial-vector meson degrees of freedom play an important role in these low-energy processes and that a reasonable theoretical description requires globally chirally invariant terms other than the vector-meson mass term. An important question for meson vacuum phenomenology is the quark content of the physical scalar f{sub 0}(600) and a{sub 0}(980) mesons. We investigate this question by assigning the quark-antiquark {sigma} and a{sub 0} states of our model with these physical mesons. We show via a detailed comparison with experimental data that this scenario can describe all vacuum properties studied here except for the decay width of the {sigma}, which turns out to be too small. We also study the alternative assignment f{sub 0}(1370) and a{sub 0}(1450) for the scalar mesons. In this case the decay width agrees with the experimental value, but the {pi}{pi} scattering length a{sub 0}{sup 0} is too small. This indicates the necessity to extend our model by additional scalar degrees of freedom.

The Glueball in a Chiral Linear Sigma Model with Vector Mesons

We present a two-flavor linear sigma model with global chiral symmetry and (axial-)vector mesons as well as an additional glueball degree of freedom. We study the structure of the well-established scalar resonances

A LINEAR SIGMA MODEL WITH THREE FLAVORS AND VECTOR AND AXIAL-VECTOR MESONS

{f}_{0}(1370)

Masses of Axial‐Vector Resonances in a Linear Sigma Model with Nf = 3

and

Holographic Glueball Decay

{f}_{0}(1500)

Resonances

: by a fit to experimentally known decay widths we find that

f_0(1370)

{f}_{0}(1370)

and

is predominantly a

f_0(1710)

\overline{q}q

as scalar

state and