Chiral dynamics in few-nucleon systems
Chiral Effective Field Theory (EFT) has become a standard tool for analyzing the properties of hadronic systems at low energy in a systematic and controlled way based upon the approximate and spontaneously broken chiral symmetry of Quantum Chromodynamics (QCD). Based on Weinberg's idea to use chiral EFT to derive nuclear forces, this method has also been successfully applied to a few-nucleon problems. Energy-independent and hermitian nuclear potentials can be derived from the chiral Lagrangian e.g. using the method of unitary transformation. This scheme can also be applied to derive the corresponding nuclear current operator. They have used this framework to study the 2N system at next-to-next-to-next-to-leading order (N{sup 3}LO) in the chiral expansion. The theoretical uncertainty for scattering observables at N{sup 3}LO is expected to be of the order {approx} 0.5%, 7% and 25% at laboratory energy {approx} 50, 150 and 250 MeV. The findings agree well with these estimations. Three- and more-nucleon systems have been considered so far up to next-to-next-to-leading order. For the first time, the complete chiral three-nucleon force has been included in few-body calculations, which starts to contribute at this order. N{sup 3}LO analysis of > 2N systems is in progress. Recently they have worked out the leading and subleading isospin-violating 3N forces using the method of unitary transformation, which are largely driven by nucleon and pion mass differences. The work on isospin-breaking 2N forces is underway.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research (ER) (US)
- DOE Contract Number:
- AC05-84ER40150
- OSTI ID:
- 836339
- Report Number(s):
- JLAB-THY-05-299; DOE/ER/40150-3082; TRN: US0500558
- Resource Relation:
- Conference: 337th International WE-Heraeus Seminar on Effective Field Theories in Nuclear, Particle and Atomic Physics, Conference location not supplied, 12/13/2004; Other Information: PBD: 1 Dec 2004
- Country of Publication:
- United States
- Language:
- English
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Summary of Few Nucleon Working Group
Chiral effective field theory analysis of hadronic parity violation in few-nucleon systems