Eur. Phys. J. A (2013) 49: 82
https://doi.org/10.1140/epja/i2013-13082-y

Regular Article - Theoretical Physics

Dependence of the triple-alpha process on the fundamental constants of nature

¹⁹⁹¹⁸ Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44870, Bochum, Germany
²⁹⁹¹⁸ Institut für Kernphysik, Institute for Advanced Simulation, Forschungszentrum Jülich, D-52425, Jülich, Germany
³⁹⁹¹⁸ Department of Physics, North Carolina State University, 27695, Raleigh, NC, USA
⁴⁹⁹¹⁸ JARA - High Performance Computing, Forschungszentrum Jülich, D-52425, Jülich, Germany
⁵⁹⁹¹⁸ Helmholtz-Institut für Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universität Bonn, D-53115, Bonn, Germany

^* e-mail: evgeny.epelbaum@rub.de

Received: 25 March 2013
Revised: 17 June 2013
Accepted: 29 June 2013
Published online: 17 July 2013

Abstract

We present an ab initio calculation of the quark mass dependence of the ground state energies of ⁴He , ⁸Be and ¹²C , and of the energy of the Hoyle state in ¹²C . These investigations are performed within the framework of lattice chiral Effective Field Theory. We address the sensitivity of the production rate of carbon and oxygen in red giant stars to the fundamental constants of nature by considering the impact of variations in the light quark masses and the electromagnetic fine-structure constant on the reaction rate of the triple-alpha process. As carbon and oxygen are essential to life as we know it, we also discuss the implications of our findings for an anthropic view of the Universe. We find strong evidence that the physics of the triple-alpha process is driven by alpha clustering, and that shifts in the fundamental parameters at the ≃ 2–3% level are unlikely to be detrimental to the development of life. Tolerance against much larger changes cannot be ruled out at present, given the relatively limited knowledge of the quark mass dependence of the two-nucleon S -wave scattering parameters. Lattice QCD is expected to provide refined estimates of the scattering parameters in the future.