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Title: Neutrino breakup of A=3 nuclei in supernovae

Abstract

We extend the virial equation of state to include {sup 3}H and {sup 3}He nuclei, and predict significant mass-three fractions near the neutrinosphere in supernovae. While alpha particles are often more abundant, we demonstrate that energy transfer cross sections for muon and tau neutrinos at low densities are dominated by breakup of the loosely-bound {sup 3}H and {sup 3}He nuclei. The virial coefficients involving A=3 nuclei are calculated directly from the corresponding nucleon-{sup 3}H and nucleon-{sup 3}He scattering phase shifts. For the neutral-current inelastic cross sections and the energy transfer cross sections, we perform ab initio calculations based on microscopic two- and three-nucleon interactions and meson-exchange currents.

Authors:
 [1];  [2]; ;  [3];  [4];  [1]
  1. TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, V6T 2A3 (Canada)
  2. (Canada)
  3. Racah Institute of Physics, Hebrew University, 91904 Jerusalem (Israel)
  4. Nuclear Theory Center and Department of Physics, Indiana University, Bloomington, Indiana 47408 (United States)
Publication Date:
OSTI Identifier:
20995332
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 75; Journal Issue: 5; Other Information: DOI: 10.1103/PhysRevC.75.055803; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ALPHA PARTICLES; BOSON-EXCHANGE MODELS; CROSS SECTIONS; DENSITY; ENERGY TRANSFER; HELIUM 3; MASS NUMBER; MUONS; NEUTRAL CURRENTS; NUCLEONS; PHASE SHIFT; SCATTERING; TAU NEUTRINOS; TRITIUM; VIRIAL EQUATION

Citation Formats

O'Connor, E., Department of Physics, UPEI, 550 University Ave, Charlottetown, Prince Edward Island, C1A 4P3, Gazit, D., Barnea, N., Horowitz, C. J., and Schwenk, A. Neutrino breakup of A=3 nuclei in supernovae. United States: N. p., 2007. Web. doi:10.1103/PHYSREVC.75.055803.
O'Connor, E., Department of Physics, UPEI, 550 University Ave, Charlottetown, Prince Edward Island, C1A 4P3, Gazit, D., Barnea, N., Horowitz, C. J., & Schwenk, A. Neutrino breakup of A=3 nuclei in supernovae. United States. doi:10.1103/PHYSREVC.75.055803.
O'Connor, E., Department of Physics, UPEI, 550 University Ave, Charlottetown, Prince Edward Island, C1A 4P3, Gazit, D., Barnea, N., Horowitz, C. J., and Schwenk, A. Tue . "Neutrino breakup of A=3 nuclei in supernovae". United States. doi:10.1103/PHYSREVC.75.055803.
@article{osti_20995332,
title = {Neutrino breakup of A=3 nuclei in supernovae},
author = {O'Connor, E. and Department of Physics, UPEI, 550 University Ave, Charlottetown, Prince Edward Island, C1A 4P3 and Gazit, D. and Barnea, N. and Horowitz, C. J. and Schwenk, A.},
abstractNote = {We extend the virial equation of state to include {sup 3}H and {sup 3}He nuclei, and predict significant mass-three fractions near the neutrinosphere in supernovae. While alpha particles are often more abundant, we demonstrate that energy transfer cross sections for muon and tau neutrinos at low densities are dominated by breakup of the loosely-bound {sup 3}H and {sup 3}He nuclei. The virial coefficients involving A=3 nuclei are calculated directly from the corresponding nucleon-{sup 3}H and nucleon-{sup 3}He scattering phase shifts. For the neutral-current inelastic cross sections and the energy transfer cross sections, we perform ab initio calculations based on microscopic two- and three-nucleon interactions and meson-exchange currents.},
doi = {10.1103/PHYSREVC.75.055803},
journal = {Physical Review. C, Nuclear Physics},
number = 5,
volume = 75,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}
  • Neutrino emissions from electron/positron capture on the deuteron and the nucleon-nucleon fusion processes in a supernova core are studied. These weak processes are evaluated in an approach which consists of one-nucleon and two-nucleon meson-exchange currents and nuclear wave functions generated by a high precision nucleon-nucleon potential. In addition to the cross sections for these processes involving the deuteron, we present neutrino emissivities due to these processes calculated for typical profiles of core-collapsed supernovae. These novel neutrino emissivities are compared with the standard neutrino-emission mechanisms. We find that the electron-type neutrino emissivity due to electron capture on the deuteron is comparablemore » to that on the proton in the deuteron abundant region. The electron-type antineutrino emissivity due to positron capture on the deuteron is much smaller than that on the neutron. The neutrino emissivity through deuteron formation is smaller than the conventional processes, but may be important in a situation where the nucleon-nucleon bremsstrahlung is important. The implications of the new channels involving deuterons for the supernova mechanism are discussed.« less
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  • The energy distribution of deuterons from the reaction /sup 3/He+..cap alpha -->..d+p+..cap alpha.. at E/sub ..cap alpha../ = 26.3 MeV has two broad peaks, which correspond to the ground and first excited states of the /sup 5/Li nucleus. The following parameters were found for these states: E/sub 0/ = 1.93 +- 0.21 MeV, GAMMA/sub 0/ = 1.9 +- 0.25 MeV, and E/sub 1/ = 4.74 +- 0.11 MeV, GAMMA/sub 1/ = 1.64 +- 0.25 MeV (the positions and widths of the levels are given in the c.m. frame of the /sup 4/He+p pair).
  • The (..cap alpha..,/sup 3/He) breakup reaction on /sup 62/Hi and /sup 209/Bi targets at incident ..cap alpha..-particle energies of 172.5 and 140 MeV respectively has been studied by a plane-wave spectator model. The results have been compared with the Serber model calculations as well as with those of the distorted-wave Born approximation. It is found that plane wave methods are not appropriate to describe this reaction correctly. Apart from the distortions in the ..cap alpha.. and /sup 3/He channels, the proper consideration of the neutron target interaction is also very important. The validity of some of the assumptions of themore » Serber model has also been investigated. It is found that these assumptions are not valid for the reactions under investigation and consequently some of the conclusions drawn previously from the Serber model calculations for this reaction are not justified.« less
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