Microscopic Description of Isoscalar Giant Monopole Resonance in ${}^{48}$Ca

The properties of the isoscalar giant monopole resonance (ISGMR) for the double magic ${}^{48}$Ca are analyzed in the framework of a microscopic model based on Skyrme-type interactions. A method for simultaneously taking into account the coupling between one-, two-, and three-phonon terms in the wave functions of $0^{+}$ states has been developed. The inclusion of three-phonon configurations leads to a substantial redistribution of the ISGMR strength to lower energy $0^{+}$ states and also higher energy tail. Our results demonstrate that the developed approach enables to us to describe a gross structure of the ISGMR spreading width.