Article

Bottomonium in a Bethe-Salpeter-equation study

Physical review D: Particles and fields 09/2011; 84. DOI: 10.1103/PhysRevD.84.096014
Source: arXiv

ABSTRACT Using a well-established effective interaction in a rainbow-ladder truncation
model of QCD, we fix the remaining model parameter to the bottomonium
ground-state spectrum in a covariant Bethe-Salpeter equation approach and find
surprisingly good agreement with the available experimental data including the
2^{--} Upsilon(1D) state. Furthermore, we investigate the consequences of such
a fit for charmonium and light-quark ground states.

0 Bookmarks
 · 
119 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We compute the axial and pseudoscalar form factors of the nucleon in the Dyson-Schwinger approach. To this end, we solve a covariant three-body Faddeev equation for the nucleon wave function and determine the matrix elements of the axialvector and pseudoscalar isotriplet currents. Our only input is a well-established and phenomenologically successful ansatz for the nonperturbative quark-gluon interaction. As a consequence of the axial Ward-Takahashi identity that is respected at the quark level, the Goldberger-Treiman relation is reproduced for all current-quark masses. We discuss the timelike pole structure of the quark-antiquark vertices that enters the nucleon matrix elements and determines the momentum dependence of the form factors. Our result for the axial charge underestimates the experimental value by 20-25% which might be a signal of missing pion-cloud contributions. The axial and pseudoscalar form factors agree with phenomenological and lattice data in the momentum range above Q^2 ~ 1...2 GeV^2.
    European Physical Journal A 11/2011; 48(1). · 2.42 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: I present a brief overview of the Dyson-Schwinger approach and its application to hadron properties. Recent results for baryon and tetraquark masses as well as nucleon and Δ elastic and transition form factors are discussed.
    Journal of Physics Conference Series 03/2013; 426(1):2014-.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We derive the expression for the nonperturbative coupling of a hadron to two external currents from its underlying structure in QCD. Microscopically, the action of each current is resolved to a coupling with dressed quarks. The Lorentz structure of the currents is arbitrary and thereby allows to describe the hadron’s interaction with photons as well as mesons in the same framework. We analyze the ingredients of the resulting four-point functions and explore their potential to describe a variety of processes relevant in experiments. Possible applications include Compton scattering, the study of two-photon effects in hadron form factors, pion photo- and electroproduction on a nucleon, nucleon-pion or pion-pion scattering.
    Physical review D: Particles and fields 02/2012; 85(3).

Full-text

Download
0 Downloads
Available from