297 research outputs found
The Coulomb interaction in Helium-3: Interplay of strong short-range and weak long-range potentials
Quantum chromodynamics and the electroweak theory at low energies are
prominent instances of the combination of a short-range and a long-range
interaction. For the description of light nuclei, the large nucleon-nucleon
scattering lengths produced by the strong interaction, and the reduction of the
weak interaction to the Coulomb potential, play a crucial role. Helium-3 is the
first bound nucleus comprised of more than one proton in which this combination
of forces can be studied.
We demonstrate a proper renormalization of Helium-3 using the pionless
effective field theory as the formal representation of the nuclear regime as
strongly interacting fermions. The theory is found consistent at leading and
next-to-leading order without isospin-symmetry-breaking 3-nucleon interactions
and a non-perturbative treatment of the Coulomb interaction. The conclusion
highlights the significance of the regularization method since a comparison to
previous work is contradictory if the difference in those methods is not
considered.
With a perturbative Coulomb interaction, as suggested by dimensional
analysis, we find the Helium-3 system properly renormalized, too.
For both treatments, renormalization-scheme independence of the effective
field theory is demonstrated by regulating the potential and a variation of the
associated cutoff.Comment: accepted version; additional figure; additional discussion of renorm.
and limit cycl
Efimov physics from a renormalization group perspective
We discuss the physics of the Efimov effect from a renormalization group
viewpoint using the concept of limit cycles. Furthermore, we discuss recent
experiments providing evidence for the Efimov effect in ultracold gases and its
relevance for nuclear systems.Comment: 22 pages, 4 figures (invited review submitted to Phil. Trans. Roy.
Soc. A
Criminal Procedure: The Legal Mechanics after Arrest and Investigation
Criminal Procedure: The Legal Mechanics after Arrest and Investigatio
Spectra and Scattering of Light Lattice Nuclei from Effective Field Theory
An effective field theory is used to describe light nuclei, calculated from
quantum chromodynamics on a lattice at unphysically large pion masses. The
theory is calibrated at leading order to two available data sets on two- and
three-body nuclei for two pion masses. At those pion masses we predict the
quartet and doublet neutron-deuteron scattering lengths, and the alpha-particle
binding energy. For MeV we obtain, respectively, fm, fm, and MeV, while for MeV fm, fm, and MeV are found. Phillips- and
Tjon-like correlations to the triton binding energy are established.
Higher-order effects on the respective correlation bands are found insensitive
to the pion mass. As a benchmark, we present results for the physical pion
mass, using experimental two-body scattering lengths and the triton binding
energy as input. Hints of subtle changes in the structure of the triton and
alpha particle are discussed.Comment: 19 pages, 8 figures, 4 tables, submitted to PR
- …