%0 Journal Article %T On the spectral functions of scalar mesons %A Giacosa %A Francesco %A Pagliara %A Giuseppe %J High Energy Physics - Phenomenology %D 2007 %I %R 10.1103/PhysRevC.76.065204 %X In this work we study the spectral functions of scalar mesons in one- and two-channel cases. When the propagators satisfy the K\"allen-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. %U http://arxiv.org/abs/0707.3594