Supernova neutrinos and antineutrinos: ternary luminosity diagram and spectral split patterns

Journal Article · Thu Oct 01 04:00:00 EDT 2009 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2009/10/002· OSTI ID:22273053

Fogli, Gianluigi; Marrone, Antonio; Tamborra, Irene ^[1]; Lisi, Eligio ^[2]

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1. Dipartimento Interateneo di Fisica ''Michelangelo Merlin'', Via Amendola 173, 70126 Bari (Italy)
2. Istituto Nazionale di Fisica Nucleare, Sezione di Bari, Via Orabona 4, 70126 Bari (Italy)

In core-collapse supernovae, the ν{sub e} and ν-bar {sub e} species may experience collective flavor swaps to non-electron species ν{sub x}, within energy intervals limited by relatively sharp boundaries (''splits''). These phenomena appear to depend sensitively upon the initial energy spectra and luminosities. We investigate the effect of generic variations of the fractional luminosities (l{sub e}, l{sub ē}, l{sub x}) with respect to the usual ''energy equipartition'' case (1/6, 1/6, 1/6), within an early-time supernova scenario with fixed thermal spectra and total luminosity. We represent the constraint l{sub e}+l{sub ē}+4l{sub x} = 1 in a ternary diagram, which is explored via numerical experiments (in single-angle approximation) over an evenly-spaced grid of points. In inverted hierarchy, single splits arise in most cases, but an abrupt transition to double splits is observed for a few points surrounding the equipartition one. In normal hierarchy, collective effects turn out to be unobservable at all grid points but one, where single splits occur. Admissible deviations from equipartition may thus induce dramatic changes in the shape of supernova (anti)neutrino spectra. The observed patterns are interpreted in terms of initial flavor polarization vectors (defining boundaries for the single/double split transitions), lepton number conservation, and minimization of potential energy.

• OSTI ID: 22273053
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 10 Vol. 2009; ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ANTINEUTRINOS
APPROXIMATIONS
ASTROPHYSICS
COSMIC ELECTRONS
ENERGY SPECTRA
FLAVOR MODEL
GRAVITATIONAL COLLAPSE
LEPTON NUMBER
LIMITING VALUES
LUMINOSITY
POLARIZATION
POTENTIAL ENERGY
SUPERNOVAE
VECTORS