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Chiral three-nucleon forces from p-wave pion production
C Hanhart1, van Kolck U, G A Miller
1Department of Physics, University of Washington, Box 351560, Seattle, Washington 98195-1560, USA.
Physical Review Letters
|September 27, 2000
Summary
This study analyzes p-wave pion production in nucleon-nucleon collisions using chiral symmetry. The improved model shows good agreement with experimental data for spin-triplet cross sections without free parameters.
Area of Science:
- Nuclear Physics
- Particle Physics
- Quantum Chromodynamics
Background:
- Understanding pion production in nucleon-nucleon collisions is crucial for nuclear structure and reactions.
- Chiral symmetry provides fundamental constraints on low-energy quantum chromodynamics.
Purpose of the Study:
- To investigate p-wave pion production in nucleon-nucleon collisions.
- To apply an improved power counting scheme that respects chiral symmetry constraints.
- To compare theoretical predictions with experimental data.
Main Methods:
- Calculation of contributions from the first two nonvanishing orders in an improved chiral effective field theory power counting.
- Analysis of spin-triplet and spin-singlet cross sections for specific reactions (pp-->pppi(0) and pp-->pnpi(+)).
Main Results:
- The model demonstrates reasonable convergence and agreement with experimental data for the spin-triplet cross section (pp-->pppi(0)) without employing free parameters.
- The calculated spin-singlet cross section (pp-->pnpi(+)) provides constraints on a short-range operator.
Conclusions:
- The improved power counting provides a robust framework for studying pion production in nucleon-nucleon interactions.
- The results highlight the importance of specific short-range operators in understanding three-nucleon forces.