Lohs, Andreas (2015)
Neutrino Reactions in Hot and Dense Matter.
Technische Universität Darmstadt
Dissertation, Erstveröffentlichung
Kurzbeschreibung (Abstract)
In this thesis, neutrino reactions in hot and dense matter are studied. In particular, this work is concerned with neutrino-matter interactions that are relevant for neutrino transport in core-collapse supernovae (CCSNe). The majority of the energy from a CCSN is released in the form of neutrinos. Accurate understanding and computation of these interactions is most relevant to achieve sufficiently reliable predictions for the evolution of CCSNe and other related question such as the production of heavy elements or neutrino oscillations.
For this purpose this work follows the combined approach of searching for new important neutrino reactions and improving the computation of those reactions that are already implemented.
First we estimate the relevance of charged-current weak interactions that include muon-neutrinos or muons, as well as the role of neutron decay for neutrino transport in CCSNe. All of these reactions were previously neglected in CCSN-simulations. We derive and compute the matrix element and subsequent semi-analytic expressions for transport properties like the inverse mean free path of the new reactions. It is found that these reactions are important for muon neutrinos and low energy electron antineutrinos at very high densities in the protoneutron star surface. Consequently their implementation might lead to several changes in the prediction of CCSNe signatures such as the nucleosynthesis yields.
Second we improve the precision in the computation of well known neutrino-nucleon reactions like neutrino absorption on neutrons. We derive semi-analytic expressions for transport properties that use less restrictive approximations while keeping the computational demand constant. Therefore we consider the full relativistic kinematics of all participating particles i.e. allowing for relativistic nucleons and finite lepton masses. Also the weak magnetism terms of the matrix elements are explicitly included to all orders.
From our results we suggest that the new neutrino reactions should be included in future dynamic CCSN-simulations to achieve quantitative conclusions of their impact on neutrino transport. Also we recommend the use of more precise computation schemes for neutrino rates when studying neutrino-nucleon interactions at large densities, where the strong interaction between nucleons becomes important.
| Typ des Eintrags: | Dissertation | ||||
|---|---|---|---|---|---|
| Erschienen: | 2015 | ||||
| Autor(en): | Lohs, Andreas | ||||
| Art des Eintrags: | Erstveröffentlichung | ||||
| Titel: | Neutrino Reactions in Hot and Dense Matter | ||||
| Sprache: | Englisch | ||||
| Referenten: | Martinez-Pinedo, Prof. Gabriel ; Friman, Prof. Bengt | ||||
| Publikationsjahr: | 10 Februar 2015 | ||||
| Ort: | Darmstadt | ||||
| Datum der mündlichen Prüfung: | 13 April 2015 | ||||
| URL / URN: | http://tuprints.ulb.tu-darmstadt.de/4640 | ||||
| Kurzbeschreibung (Abstract): | In this thesis, neutrino reactions in hot and dense matter are studied. In particular, this work is concerned with neutrino-matter interactions that are relevant for neutrino transport in core-collapse supernovae (CCSNe). The majority of the energy from a CCSN is released in the form of neutrinos. Accurate understanding and computation of these interactions is most relevant to achieve sufficiently reliable predictions for the evolution of CCSNe and other related question such as the production of heavy elements or neutrino oscillations. For this purpose this work follows the combined approach of searching for new important neutrino reactions and improving the computation of those reactions that are already implemented. First we estimate the relevance of charged-current weak interactions that include muon-neutrinos or muons, as well as the role of neutron decay for neutrino transport in CCSNe. All of these reactions were previously neglected in CCSN-simulations. We derive and compute the matrix element and subsequent semi-analytic expressions for transport properties like the inverse mean free path of the new reactions. It is found that these reactions are important for muon neutrinos and low energy electron antineutrinos at very high densities in the protoneutron star surface. Consequently their implementation might lead to several changes in the prediction of CCSNe signatures such as the nucleosynthesis yields. Second we improve the precision in the computation of well known neutrino-nucleon reactions like neutrino absorption on neutrons. We derive semi-analytic expressions for transport properties that use less restrictive approximations while keeping the computational demand constant. Therefore we consider the full relativistic kinematics of all participating particles i.e. allowing for relativistic nucleons and finite lepton masses. Also the weak magnetism terms of the matrix elements are explicitly included to all orders. From our results we suggest that the new neutrino reactions should be included in future dynamic CCSN-simulations to achieve quantitative conclusions of their impact on neutrino transport. Also we recommend the use of more precise computation schemes for neutrino rates when studying neutrino-nucleon interactions at large densities, where the strong interaction between nucleons becomes important. |
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| URN: | urn:nbn:de:tuda-tuprints-46407 | ||||
| Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 500 Naturwissenschaften und Mathematik > 530 Physik | ||||
| Fachbereich(e)/-gebiet(e): | 05 Fachbereich Physik > Institut für Kernphysik 05 Fachbereich Physik |
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| Hinterlegungsdatum: | 02 Aug 2015 19:55 | ||||
| Letzte Änderung: | 02 Aug 2015 19:55 | ||||
| PPN: | |||||
| Referenten: | Martinez-Pinedo, Prof. Gabriel ; Friman, Prof. Bengt | ||||
| Datum der mündlichen Prüfung / Verteidigung / mdl. Prüfung: | 13 April 2015 | ||||
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