An update on fine-tunings in the triple-alpha process

Abstract

The triple-alpha process, whereby evolved stars create carbon and oxygen, is believed to be fine-tuned to a high degree. Such fine-tuning is suggested by the unusually strong temperature dependence of the triple-alpha reaction rate at stellar temperatures. This sensitivity is due to the resonant character of the triple-alpha process, which proceeds through the so-called "Hoyle state" of ${}^{12}$C with spin-parity $0^{+}$. The question of fine-tuning can be studied within the {\it ab initio} framework of nuclear lattice effective field theory, which makes it possible to relate {\it ad hoc} changes in the energy of the Hoyle state to changes in the fundamental parameters of the nuclear Hamiltonian, which are the light quark mass $m_q$ and the electromagnetic fine-structure constant. Here, we update the effective field theory calculation of the sensitivity of the triple-alpha process to small changes in the fundamental parameters. In particular, we consider recent high-precision lattice QCD calculations of the nucleon axial coupling $g_A$, as well as new and more comprehensive results from stellar simulations of the production of carbon and oxygen. While the updated stellar simulations allow for much larger {\it ad hoc} shifts in the Hoyle state energy than previously thought, recent lattice QCD results for the nucleon S-wave singlet and triplet scattering lengths now disfavor the scenario of no fine-tuning in the light quark mass $m_q$.

arXiv comment9 pages, 2 figures, contribution to the EPJA topical issue on "The tower of effective (field) theories and the emergence of nuclear phenomena"

References in corpus (31)

• Modules for Experiments in Stellar Astrophysics (MESA)
• Modules for Experiments in Stellar Astrophysics (MESA): Giant Planets, Oscillations, Rotation, and Massive Stars
• FLAG Review 2019
• High-precision determination of the pion-nucleon $\sigma$-term from Roy-Steiner equations
• A percent-level determination of the nucleon axial coupling from Quantum Chromodynamics
• Mesonic low-energy constants
• Novel quark smearing for hadrons with high momenta in lattice QCD
• Proton Mass Decomposition from the QCD Energy Momentum Tensor
• The Deuteron and Exotic Two-Body Bound States from Lattice QCD
• Two Nucleon Systems at $m_{\pi }\sim 450\mathrm{MeV}$ from Lattice QCD
• Helium nuclei, deuteron and dineutron in 2+1 flavor lattice QCD
• Resonance saturation for four-nucleon operators
• Direct Evaluation of the Quark Content of Nucleons from Lattice QCD at the Physical Point
• Viability of carbon-based life as a function of the light quark mass
• Stellar production rates of carbon and its abundance in the universe
• Lattice QCD study of the $H$ dibaryon using hexaquark and two-baryon interpolators
• Varying the light quark mass: impact on the nuclear force and Big Bang nucleosynthesis
• Extracting the sigma-term from low-energy pion-nucleon scattering
• Low Energy Theorems For Nucleon-Nucleon Scattering
• The nucleon axial-vector coupling beyond one loop
• Dependence of the triple-alpha process on the fundamental constants of nature
• Remarks on the pion-nucleon sigma-term
• The Degree of Fine-Tuning in our Universe -- and Others
• Low-energy theorems for nucleon-nucleon scattering at unphysical pion masses
• Anthropic considerations in nuclear physics
• Neutron-proton scattering with lattice chiral effective field theory at next-to-next-to-next-to-leading order
• Low-energy theorems for nucleon-nucleon scattering at $M_{\pi }=450$ MeV
• Sensitivity of Carbon and Oxygen Yields to the Triple-Alpha Resonance in Massive Stars
• Sanity check for $NN$ bound states in lattice QCD with Lüscher's finite volume formula -- Exposing Symptoms of Fake Plateaux --
• Two-nucleon scattering in a modified Weinberg approach with a symmetry-preserving regularization
• Phenomenological view on baryon-baryon potentials from lattice QCD simulations

Cited by in corpus (6)

• 50 Years of Quantum Chromodynamics
• Nuclear Currents in Chiral Effective Field Theory
• $\theta$-dependence of light nuclei and nucleosynthesis
• Alpha-alpha scattering in the Multiverse
• Subleading contributions to the nuclear scalar isoscalar currents
• Improved Constraints on the Variation of the Weak Scale from Big Bang Nucleosynthesis