9 research outputs found
The Neutrino Signal in Stellar Core Collapse and Postbounce Evolution
General relativistic multi-group and multi-flavor Boltzmann neutrino
transport in spherical symmetry adds a new level of detail to the numerical
bridge between microscopic nuclear and weak interaction physics and the
macroscopic evolution of the astrophysical object. Although no supernova
explosions are obtained, we investigate the neutrino luminosities in various
phases of the postbounce evolution for a wide range of progenitor stars between
13 and 40 solar masses. The signal probes the dynamics of material layered in
and around the protoneutron star and is, within narrow limits, sensitive to
improvements in the weak interaction physics. Only changes that dramatically
exceed physical limitations allow experiments with exploding models. We discuss
the differences in the neutrino signal and find the electron fraction in the
innermost ejecta to exceed 0.5 as a consequence of thermal balance and weak
equilibrium at the masscut.Comment: 8 pages, 4 figures. Proceedings of the Nuclear Physics in
Astrophysics Conference, Debrecen, Hungary, 2002, to appear in Nuc. Phys. A.
Color figures added and reference actualize
Differential Neutrino Rates and Emissivities from the Plasma Process in Astrophysical Systems
The differential rates and emissivities of neutrino pairs from an equilibrium
plasma are calculated for the wide range of density and temperature encountered
in astrophysical systems. New analytical expressions are derived for the
differential emissivities which yield total emissivities in full agreement with
those previously calculated. The photon and plasmon pair production and
absorption kernels in the source term of the Boltzmann equation for neutrino
transport are provided. The appropriate Legendre coefficients of these kernels,
in forms suitable for multi-group flux-limited diffusion schemes are also
computed.Comment: 27 pages and 10 figures. Submitted to Phys. Rev.
The photo-neutrino process in astrophysical systems
Explicit expressions for the differential and total rates and emissivities of
neutrino pairs from the photo-neutrino process in hot and dense matter are derived. Full information about the
emitted neutrinos is retained by evaluating the squared matrix elements for
this process which was hitherto bypassed through the use of Lenard's identity
in obtaining the total neutrino emissivities. Accurate numerical results are
presented for widely varying conditions of temperature and density. Analytical
results helpful in understanding the qualitative behaviors of the rates and
emissivities in limiting situations are derived. The corresponding production
and absorption kernels in the source term of the Boltzmann equation for
neutrino transport are developed. The appropriate Legendre coefficients of
these kernels, in forms suitable for multigroup flux-limited diffusion schemes
are also provided.Comment: 26 pages and 7 figures. Version as accepted in Phys. Rev. D; three
figures and related discussion revise
Myth - Conceptions of World War I in Selected Diaries and Fictional Diaries Written by and for Children
Diaries and epistolatory prose for children both convey and imply a sense of veracity about the factual, social and historical content combined with emotional realism i.e. because the first person narrative is used and the diary recounts personal experience the intimation is that there is a reality, and a set of âtruthsâ which underlie the work, even if it is fiction per se. Study of this epistolatory form in childrenâs literature demonstrates that through this popular form myths and misconceptions have been and are perpetuated about World War One, even in texts which purport to teach history through this kind of reading experience. The chapter also discusses the change in the representation of war to a personalised history and how this is reflected in a selection of texts for children: Valerie Wildingâs My Story, Road to War: a First World War Girlâs Diary 1916-17 (2008); Marcia Williamsâ Archieâs War (2009) and Piet Kuhrâs There We'll Meet Again: A Young German Girl's Diary of the First World War (1982)
Low-Energy Physics in Neutrino LArTPCs
International audienceIn this white paper, we outline some of the scientific opportunities and challenges related to detection and reconstruction of low-energy (less than 100 MeV) signatures in liquid argon time-projection chamber (LArTPC) detectors. Key takeaways are summarized as follows. 1) LArTPCs have unique sensitivity to a range of physics and astrophysics signatures via detection of event features at and below the few tens of MeV range. 2) Low-energy signatures are an integral part of GeV-scale accelerator neutrino interaction final states, and their reconstruction can enhance the oscillation physics sensitivities of LArTPC experiments. 3) BSM signals from accelerator and natural sources also generate diverse signatures in the low-energy range, and reconstruction of these signatures can increase the breadth of BSM scenarios accessible in LArTPC-based searches. 4) Neutrino interaction cross sections and other nuclear physics processes in argon relevant to sub-hundred-MeV LArTPC signatures are poorly understood. Improved theory and experimental measurements are needed. Pion decay-at-rest sources and charged particle and neutron test beams are ideal facilities for experimentally improving this understanding. 5) There are specific calibration needs in the low-energy range, as well as specific needs for control and understanding of radiological and cosmogenic backgrounds. 6) Novel ideas for future LArTPC technology that enhance low-energy capabilities should be explored. These include novel charge enhancement and readout systems, enhanced photon detection, low radioactivity argon, and xenon doping. 7) Low-energy signatures, whether steady-state or part of a supernova burst or larger GeV-scale event topology, have specific triggering, DAQ and reconstruction requirements that must be addressed outside the scope of conventional GeV-scale data collection and analysis pathways
Low-Energy Physics in Neutrino LArTPCs
International audienceIn this white paper, we outline some of the scientific opportunities and challenges related to detection and reconstruction of low-energy (less than 100 MeV) signatures in liquid argon time-projection chamber (LArTPC) detectors. Key takeaways are summarized as follows. 1) LArTPCs have unique sensitivity to a range of physics and astrophysics signatures via detection of event features at and below the few tens of MeV range. 2) Low-energy signatures are an integral part of GeV-scale accelerator neutrino interaction final states, and their reconstruction can enhance the oscillation physics sensitivities of LArTPC experiments. 3) BSM signals from accelerator and natural sources also generate diverse signatures in the low-energy range, and reconstruction of these signatures can increase the breadth of BSM scenarios accessible in LArTPC-based searches. 4) Neutrino interaction cross sections and other nuclear physics processes in argon relevant to sub-hundred-MeV LArTPC signatures are poorly understood. Improved theory and experimental measurements are needed. Pion decay-at-rest sources and charged particle and neutron test beams are ideal facilities for experimentally improving this understanding. 5) There are specific calibration needs in the low-energy range, as well as specific needs for control and understanding of radiological and cosmogenic backgrounds. 6) Novel ideas for future LArTPC technology that enhance low-energy capabilities should be explored. These include novel charge enhancement and readout systems, enhanced photon detection, low radioactivity argon, and xenon doping. 7) Low-energy signatures, whether steady-state or part of a supernova burst or larger GeV-scale event topology, have specific triggering, DAQ and reconstruction requirements that must be addressed outside the scope of conventional GeV-scale data collection and analysis pathways
Low-Energy Physics in Neutrino LArTPCs
International audienceIn this white paper, we outline some of the scientific opportunities and challenges related to detection and reconstruction of low-energy (less than 100 MeV) signatures in liquid argon time-projection chamber (LArTPC) detectors. Key takeaways are summarized as follows. 1) LArTPCs have unique sensitivity to a range of physics and astrophysics signatures via detection of event features at and below the few tens of MeV range. 2) Low-energy signatures are an integral part of GeV-scale accelerator neutrino interaction final states, and their reconstruction can enhance the oscillation physics sensitivities of LArTPC experiments. 3) BSM signals from accelerator and natural sources also generate diverse signatures in the low-energy range, and reconstruction of these signatures can increase the breadth of BSM scenarios accessible in LArTPC-based searches. 4) Neutrino interaction cross sections and other nuclear physics processes in argon relevant to sub-hundred-MeV LArTPC signatures are poorly understood. Improved theory and experimental measurements are needed. Pion decay-at-rest sources and charged particle and neutron test beams are ideal facilities for experimentally improving this understanding. 5) There are specific calibration needs in the low-energy range, as well as specific needs for control and understanding of radiological and cosmogenic backgrounds. 6) Novel ideas for future LArTPC technology that enhance low-energy capabilities should be explored. These include novel charge enhancement and readout systems, enhanced photon detection, low radioactivity argon, and xenon doping. 7) Low-energy signatures, whether steady-state or part of a supernova burst or larger GeV-scale event topology, have specific triggering, DAQ and reconstruction requirements that must be addressed outside the scope of conventional GeV-scale data collection and analysis pathways
Low-Energy Physics in Neutrino LArTPCs
International audienceIn this white paper, we outline some of the scientific opportunities and challenges related to detection and reconstruction of low-energy (less than 100 MeV) signatures in liquid argon time-projection chamber (LArTPC) detectors. Key takeaways are summarized as follows. 1) LArTPCs have unique sensitivity to a range of physics and astrophysics signatures via detection of event features at and below the few tens of MeV range. 2) Low-energy signatures are an integral part of GeV-scale accelerator neutrino interaction final states, and their reconstruction can enhance the oscillation physics sensitivities of LArTPC experiments. 3) BSM signals from accelerator and natural sources also generate diverse signatures in the low-energy range, and reconstruction of these signatures can increase the breadth of BSM scenarios accessible in LArTPC-based searches. 4) Neutrino interaction cross sections and other nuclear physics processes in argon relevant to sub-hundred-MeV LArTPC signatures are poorly understood. Improved theory and experimental measurements are needed. Pion decay-at-rest sources and charged particle and neutron test beams are ideal facilities for experimentally improving this understanding. 5) There are specific calibration needs in the low-energy range, as well as specific needs for control and understanding of radiological and cosmogenic backgrounds. 6) Novel ideas for future LArTPC technology that enhance low-energy capabilities should be explored. These include novel charge enhancement and readout systems, enhanced photon detection, low radioactivity argon, and xenon doping. 7) Low-energy signatures, whether steady-state or part of a supernova burst or larger GeV-scale event topology, have specific triggering, DAQ and reconstruction requirements that must be addressed outside the scope of conventional GeV-scale data collection and analysis pathways