title: Ab initio calculation of the Hoyle state.
abstract: The Hoyle state plays a crucial role in the helium burning of stars heavier than our Sun and in the production of carbon and other elements necessary for life. This excited state of the carbon-12 nucleus was postulated by Hoyle as a necessary ingredient for the fusion of three alpha particles to produce carbon at stellar temperatures. Although the Hoyle state was seen experimentally more than a half century ago nuclear theorists have not yet uncovered the nature of this state from first principles. In this Letter we report the first ab initio calculation of the low-lying states of carbon-12 using supercomputer lattice simulations and a theoretical framework known as effective field theory. In addition to the ground state and excited spin-2 state, we find a resonance at -85(3)  MeV with all of the properties of the Hoyle state and in agreement with the experimentally observed energy.
authors.affiliation: Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44870 Bochum, Germany.
authors.forename: Evgeny
authors.initials: E
authors.lastname: Epelbaum
authors.forename: Hermann
authors.initials: H
authors.lastname: Krebs
authors.forename: Dean
authors.initials: D
authors.lastname: Lee
authors.forename: Ulf-G
authors.initials: UG
authors.lastname: Meissner