Dynamical generation of hadronic resonances in effective models with derivative interactions

Abstract

Light scalar mesons can be understood as dynamically generated resonances. They arise as 'companion poles' in the propagators of quark-antiquark seed states when accounting for hadronic loop contributions to the self-energies of the latter. Such a mechanism may explain the overpopulation in the scalar sector - there exist more resonances with total spin $J=0$ than can be described within a quark model. Along this line, we study an effective Lagrangian approach where the isovector state $a_0(1450)$ couples via both non-derivative and derivative interactions to pseudoscalar mesons. It is demonstrated that the propagator has two poles: a companion pole corresponding to $a_0(980)$ and a pole of the seed state $a_0(1450)$. The positions of these poles are in quantitative agreement with experimental data. Besides that, we investigate similar models for the isodoublet state $K_0^{\ast }(1430)$ by performing a fit to $\pi K$ phase shift data in the $I=1/2,$ $J=0$ channel. We show that, in order to fit the data accurately, a companion pole for the $K_0^{\ast }(800)$, that is, the light $\kappa$, is required. A large-$N_c$ study confirms that both resonances below $1$ GeV are predominantly four-quark states, while the heavy states are quarkonia.

151 pages, 25 figures, 8 tables, PhD thesis

References in corpus (29)

• Heavy quarkonium: progress, puzzles, and opportunities
• Linear Confinement and AdS/QCD
• A Theory of Scalar Mesons
• Resonances in coupled πK,ηK scattering from quantum chromodynamics
• Identification of a Scalar Glueball
• Is f0(1710) a glueball?
• Scalar Glueball, Scalar Quarkonia, and their Mixing
• Decay channels and charmonium mass-shifts
• The nature of $\sigma$, $\kappa$, $a_0(980)$ and $f_0(980)$
• Mixing of scalar tetraquark and quarkonia states in a chiral approach
• On the spectral functions of scalar mesons
• Strong and electromagnetic decays of the light scalar mesons interpreted as tetraquark states
• Indications of a Four-Quark Structure for the X(3872) and X(3876) Particles from Recent Belle and BABAR Data
• Introduction to Chiral Perturbation Theory
• Investigation of a0-f0 mixing
• An improved study of the kappa resonance and the non-exotic $s$ wave $\pi K$ scatterings up to $\sqrt{s}=2.1$GeV of LASS data
• Role of the tetraquark in the chiral phase transition
• Re-analysis of data on a0(1450) and a0(980)
• Strong and radiative decays of the scalars f0(980) and a0(980) in a hadronic molecule approach
• Vector and axialvector mesons at nonzero temperature within a gauged linear sigma model
• The origin of light $0^{+}$ scalar resonances
• The role of the next-to-leading order triangle-shaped diagram in two-body hadronic decays
• Propagator poles and an emergent stable state below threshold: general discussion and the E(38) state
• Radiative $\varphi$ decays with derivative interactions
• Quarkonium Phenomenology in Vacuum
• Reply to the "Comment on `Once more about the $K\bar{K}$ molecule approach to the light scalars' "
• Comment on "Once more about the KK molecule approach to the light scalars"
• The QCD vacuum and its hadronic excitations
• The scalar-isovector sector in the extended Linear Sigma Model