On the spectral functions of scalar mesons
arXiv:0707.3594 · doi:10.1103/PhysRevC.76.065204
Abstract
In this work we study the spectral functions of scalar mesons in one- and two-channel cases. When the propagators satisfy the Källen-Lehman representation a normalized spectral function is obtained, allowing to take into account finite-width effects in the evaluation of decay rates. In the one-channel case, suitable to the light sigma and k mesons, the spectral function can deviate consistently from a Breit-Wigner shape. In the two-channel case with one subthreshold channel the evaluated spectral function is well approximated by a Flatte' distribution; when applying the study to the a_0(980) and f_0(980) mesons the tree-level forbidden KK decay is analysed.
13 pages, 7 figures