Is there a Pronounced Giant Dipole Resonance in ^4He?

Abstract

A four-nucleon calculation of the total ^4He photodisintegration cross section is performed. The full final-state interaction is taken into account for the first time. This is achieved via the method of the Lorentz integral transform. Semi-realistic NN interactions are employed. Different from the known partial two-body ^4He(\gamma,n)^3He and ^4He(\gamma,p)^3H cross sections our total cross section exhibits a pronounced giant resonance. Thus, in contrast to older $(\gamma ,np)$ data, we predict quite a strong contribution of the $(\gamma ,np)$ channel at the giant resonance peak energy.

Comments: 10 pages, Latex (REVTEX), 4 Postscript figures, to appear in Phys. Rev. Lett