On the mass, width and coupling constants of the $f_0(980)$

R. Escribano; A. Gallegos; J.L. Lucio M.; G. Moreno; J. Pestieau

doi:doi:10.1140/epjc/s2003-01140-6

EPJ

a
b
d
e
ap
st
h
plus

2019 Impact factor 4.389

Particles and Fields

Eur. Phys. J. C 28, 107-114 (2003)
DOI: 10.1140/epjc/s2003-01140-6

On the mass, width and coupling constants of the f₀(980)

R. Escribano¹, A. Gallegos², J.L. Lucio M.², G. Moreno² and J. Pestieau³

¹ Grup de Física Teòrica and IFAE, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona), Spain
² Instituto de Física, Universidad de Guanajuato, Lomas del Bosque #103, Lomas del Campestre, 37150 León, Guanajuato, Mexico
³ Institut de Physique Théorique, Université Catholique de Louvain, Chemin du Cyclotron 2, 1348 Louvain-la-Neuve, Belgium

(Received: 6 June 2002 / Revised version: 21 October 2002 / Published online: 3 March 2003)

Abstract
Using the pole approach we determine the mass and width of the f₀(980); in particular, we analyze the possibility that two nearby poles are associated to it. We restrict our analysis to a neighborhood of the resonance, using $\pi\pi$ data for the phase shift and inelasticity, and the invariant mass spectrum of the $J/\psi\rightarrow\phi\pi\pi, \phi K\bar K$ decays. The formalism we use is based on unitarity and a generalized version of the Breit-Wigner parameterization. We find that a single pole describes the f₀(980), the precise position depending upon the $\pi\pi$ data used. As a byproduct, values for the $g_{f_0\pi\pi}$ and $g_{f_0K\bar K}$ coupling constants are obtained.