A New Mechanism for Generating Particle Number Asymmetry through Interactions
A new mechanism for generating particle number asymmetry (PNA) has been developed. This mechanism is realized with a Lagrangian including a complex scalar field and a neutral scalar field. The complex scalar carries U(1) charge which is associated with the PNA. It is written in terms of the condensa...
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| Format: | Article |
| Language: | English |
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Wiley
2019-01-01
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| Series: | Advances in High Energy Physics |
| Online Access: | http://dx.doi.org/10.1155/2019/6825104 |
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| author | Takuya Morozumi Keiko I. Nagao Apriadi Salim Adam Hiroyuki Takata |
| author_facet | Takuya Morozumi Keiko I. Nagao Apriadi Salim Adam Hiroyuki Takata |
| author_sort | Takuya Morozumi |
| collection | DOAJ |
| description | A new mechanism for generating particle number asymmetry (PNA) has been developed. This mechanism is realized with a Lagrangian including a complex scalar field and a neutral scalar field. The complex scalar carries U(1) charge which is associated with the PNA. It is written in terms of the condensation and Green’s function, which is obtained with two-particle irreducible (2PI) closed time path (CTP) effective action (EA). In the spatially flat universe with a time-dependent scale factor, the time evolution of the PNA is computed. We start with an initial condition where only the condensation of the neutral scalar is nonzero. The initial condition for the fields is specified by a density operator parameterized by the temperature of the universe. With the above initial conditions, the PNA vanishes at the initial time and later it is generated through the interaction between the complex scalar and the condensation of the neutral scalar. We investigate the case that both the interaction and the expansion rate of the universe are small and include their effects up to the first order of the perturbation. The expanding universe causes the effects of the dilution of the PNA, freezing interaction, and the redshift of the particle energy. As for the time dependence of the PNA, we found that PNA oscillates at the early time and it begins to dump at the later time. The period and the amplitude of the oscillation depend on the mass spectrum of the model, the temperature, and the expansion rate of the universe. |
| format | Article |
| id | doaj-art-6463452e63ec425181c3014a6556e4e5 |
| institution | Kabale University |
| issn | 1687-7357 1687-7365 |
| language | English |
| publishDate | 2019-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Advances in High Energy Physics |
| spelling | doaj-art-6463452e63ec425181c3014a6556e4e52025-08-20T03:34:25ZengWileyAdvances in High Energy Physics1687-73571687-73652019-01-01201910.1155/2019/68251046825104A New Mechanism for Generating Particle Number Asymmetry through InteractionsTakuya Morozumi0Keiko I. Nagao1Apriadi Salim Adam2Hiroyuki Takata3Graduate School of Science, Hiroshima University, Higashi-Hiroshima, 739-8526, JapanNational Institute of Technology, Niihama College, Ehime, 792-8580, JapanGraduate School of Science, Hiroshima University, Higashi-Hiroshima, 739-8526, JapanTomsk State Pedagogical University, Tomsk, 634061, RussiaA new mechanism for generating particle number asymmetry (PNA) has been developed. This mechanism is realized with a Lagrangian including a complex scalar field and a neutral scalar field. The complex scalar carries U(1) charge which is associated with the PNA. It is written in terms of the condensation and Green’s function, which is obtained with two-particle irreducible (2PI) closed time path (CTP) effective action (EA). In the spatially flat universe with a time-dependent scale factor, the time evolution of the PNA is computed. We start with an initial condition where only the condensation of the neutral scalar is nonzero. The initial condition for the fields is specified by a density operator parameterized by the temperature of the universe. With the above initial conditions, the PNA vanishes at the initial time and later it is generated through the interaction between the complex scalar and the condensation of the neutral scalar. We investigate the case that both the interaction and the expansion rate of the universe are small and include their effects up to the first order of the perturbation. The expanding universe causes the effects of the dilution of the PNA, freezing interaction, and the redshift of the particle energy. As for the time dependence of the PNA, we found that PNA oscillates at the early time and it begins to dump at the later time. The period and the amplitude of the oscillation depend on the mass spectrum of the model, the temperature, and the expansion rate of the universe.http://dx.doi.org/10.1155/2019/6825104 |
| spellingShingle | Takuya Morozumi Keiko I. Nagao Apriadi Salim Adam Hiroyuki Takata A New Mechanism for Generating Particle Number Asymmetry through Interactions Advances in High Energy Physics |
| title | A New Mechanism for Generating Particle Number Asymmetry through Interactions |
| title_full | A New Mechanism for Generating Particle Number Asymmetry through Interactions |
| title_fullStr | A New Mechanism for Generating Particle Number Asymmetry through Interactions |
| title_full_unstemmed | A New Mechanism for Generating Particle Number Asymmetry through Interactions |
| title_short | A New Mechanism for Generating Particle Number Asymmetry through Interactions |
| title_sort | new mechanism for generating particle number asymmetry through interactions |
| url | http://dx.doi.org/10.1155/2019/6825104 |
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