Local chiral interactions and magnetic structure of few-nucleon systems
| Autor: | Robert B. Wiringa, A. Kievsky, Michele Viviani, Steven C. Pieper, Luca Girlanda, Alessandro Lovato, Rocco Schiavilla, M. Piarulli, Alessandro Baroni, Laura Elisa Marcucci, Saori Pastore |
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| Přispěvatelé: | Schiavilla, R., Baroni, A., Pastore, S., Piarulli, M., Girlanda, L., Kievsky, A., Lovato, A., Marcucci, L. E., Pieper, S. C., Viviani, M., Wiringa, R. B. |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Physics
Magnetic moment Magnetic structure Nuclear Theory 010308 nuclear & particles physics FOS: Physical sciences 01 natural sciences Momentum Nuclear Theory (nucl-th) Photodisintegration Quantum mechanics 0103 physical sciences Configuration space Electric dipole transition 010306 general physics Nucleon Wave function Nuclear Experiment Few-nucleon systems chiral effective theory |
| Popis: | The magnetic form factors of $^2$H, $^3$H, and $^3$He, deuteron photodisintegration cross sections at low energies, and deuteron threshold electrodisintegration cross sections at backward angles in a wide range of momentum transfers, are calculated with the chiral two-nucleon (and three-nucleon) interactions including $\Delta$ intermediate states that have recently been constructed in configuration space. The $A\,$=$\,$3 wave functions are obtained from hyperspherical-harmonics solutions of the Schr\"odinger equation. The electromagnetic current includes one- and two-body terms, the latter induced by one- and two-pion exchange (OPE and TPE, respectively) mechanisms and contact interactions. The contributions associated with $\Delta$ intermediate states are only retained at the OPE level, and are neglected in TPE loop (tree-level) corrections to two-body (three-body) current operators. Expressions for these currents are derived and regularized in configuration space for consistency with the interactions. The low-energy constants that enter the contact few-nucleon systems. The predicted form factors and deuteron electrodisintegration cross section are in excellent agreement with experiment for momentum transfers up to 2--3 fm$^{-1}$. However, the experimental values for the deuteron photodisintegration cross section are consistently underestimated by theory, unless use is made of the Siegert form of the electric dipole transition operator. A complete analysis of the results is provided, including the clarification of the origin of the aforementioned discrepancy. Comment: 24 pages, 13 figures |
| Databáze: | OpenAIRE |
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