科研之友
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摘要
We discuss the diffuse flux of electron neutrinos and antineutrinos from cosmological failed supernovae, stars that collapse directly into a black hole with no explosion. This flux has a hotter energy spectrum compared to the flux from regular, neutron star-forming collapses and therefore it dominates the total diffuse flux from core collapses above 20-45 MeV of neutrino energy. Reflecting the features of the originally emitted neutrinos, the flux of v(e) and (v) over bar (e) at Earth is larger when the survival probability of these species is larger, and also when the equations of state of nuclear matter are stiffer. In the 19-29 MeV energy window, the flux from failed supernovae is substantial, ranging from similar to 7% to a dominant fraction of the total flux from all core collapses. It can be as large as phi(BH)((v) over bare) = 0.38 s(-1) cm(-2) for (v) over bar (e) and as large as phi(BH)((v) over bare) = 0.28 s(-1) cm(-2) for (v) over bar (e), normalized to a local rate of core collapses of Rcc (0) = 10(-4) yr(-1) Mpc(-3). In 5 years, a 0.45 Mt water Cherenkov detector should see similar to 5-65 events from failed supernovae, while up to similar to 160 events are expected for the same mass with Gadolinium added. A 0.1 Mt liquid argon experiment should record similar to 1-11 events. Signatures of neutrinos from failed supernovae are the enhancement of the total rates of events from core collapses (up to a factor of similar to 2) and the appearance of high energy tails in the event spectra.
- 出版日期2012-2-14
