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Photoabsorption on 4He with a realistic nuclear force
Doron Gazit1, Sonia Bacca, Nir Barnea
1The Racah Institute of Physics, The Hebrew University, 91904 Jerusalem, Israel.
Physical Review Letters
|April 12, 2006
Summary
This study calculates the helium-4 total photoabsorption cross section using advanced nuclear potentials. Three-nucleon forces significantly impact results, especially above 50 MeV.
Area of Science:
- Nuclear Physics
- Quantum Chromodynamics
Background:
- The photoabsorption cross section of helium-4 (4He) is crucial for understanding nuclear structure and interactions.
- Realistic nucleon-nucleon potentials and three-nucleon forces (3NF) are essential for accurate nuclear calculations.
Purpose of the Study:
- To calculate the 4He total photoabsorption cross section using the Argonne V18 nucleon-nucleon potential and the Urbana IX 3NF.
- To rigorously include final state interactions and analyze the impact of 3NF on the cross section.
Main Methods:
- Lorentz integral transform method for rigorous inclusion of final state interaction.
- Calculation of the 4He total photoabsorption cross section with and without 3NF.
Main Results:
- A pronounced giant resonance was observed, with peak cross sections of 3.0 mb (with 3NF) and 3.2 mb (without 3NF).
- Above 50 MeV, 3NF effects were significant, reaching up to 35%.
- Good agreement with experimental data was found near the photoabsorption threshold.
Conclusions:
- The study highlights the significant role of three-nucleon forces in the photoabsorption of 4He.
- While agreement near threshold is good, experimental data in the giant resonance region is inconclusive for a definitive comparison.
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