dorsal/arxiv
View SchemaCoherent two pion photoproduction on 12C
| Authors | S. S. Kamalov, E. Oset |
|---|---|
| Categories | |
| ArXiv ID | nucl-th/9704024 |
| URL | https://arxiv.org/abs/nucl-th/9704024 |
| DOI | 10.1016/S0375-9474(97)00372-2 |
| Journal | Nucl.Phys. A625 (1997) 873-892 |
Abstract
We develop the formalism for coherent two pion photoproduction in nuclei and perform actual calculations of cross sections for $\pi^-\pi^+$ and $\pi^0\pi^0$ photoproduction on $^{12}C$. We find that due to the isospin symmetry the cross section for $\pi^0\pi^0$ production is very small and has a maximum when the pions propagate together. However, the kinematical region where the energies and polar angles of the two $\pi^0$ mesons are equal and their relative azimuthal angle $\phi=180^0$ is forbidden. Conversely in the $\pi^-\pi^+$ production the pions prefer to have a relative azimuthal angle 180$^0$ and the production of the pions propagating together is suppressed. The dominant one-body mechanism in both channels is related to the excitation of the $\Delta$ isobar. Hence the reaction can serve as a source of information about $\Delta$'s properties in nucleus. We have found that the reaction is sensitive to effects of the pion and $\Delta$ renormalization in the nuclear medium, similar to those found in the coherent $(\gamma,\pi^0)$ reaction, but magnified because of the presence of the two pions.
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"abstract": "We develop the formalism for coherent two pion photoproduction in nuclei and\nperform actual calculations of cross sections for $\\pi^-\\pi^+$ and $\\pi^0\\pi^0$\nphotoproduction on $^{12}C$. We find that due to the isospin symmetry the cross\nsection for $\\pi^0\\pi^0$ production is very small and has a maximum when the\npions propagate together. However, the kinematical region where the energies\nand polar angles of the two $\\pi^0$ mesons are equal and their relative\nazimuthal angle $\\phi=180^0$ is forbidden. Conversely in the $\\pi^-\\pi^+$\nproduction the pions prefer to have a relative azimuthal angle 180$^0$ and the\nproduction of the pions propagating together is suppressed. The dominant\none-body mechanism in both channels is related to the excitation of the\n$\\Delta$ isobar. Hence the reaction can serve as a source of information about\n$\\Delta$\u0027s properties in nucleus. We have found that the reaction is sensitive\nto effects of the pion and $\\Delta$ renormalization in the nuclear medium,\nsimilar to those found in the coherent $(\\gamma,\\pi^0)$ reaction, but magnified\nbecause of the presence of the two pions.",
"arxiv_id": "nucl-th/9704024",
"authors": [
"S. S. Kamalov",
"E. Oset"
],
"categories": [
"nucl-th"
],
"doi": "10.1016/S0375-9474(97)00372-2",
"journal_ref": "Nucl.Phys. A625 (1997) 873-892",
"title": "Coherent two pion photoproduction on 12C",
"url": "https://arxiv.org/abs/nucl-th/9704024"
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