Analysis of the SN 1987A neutrinos with a flexible spectral shape

Mirizzi, Alessandro; Raffelt, Georg G.

doi:10.1103/physrevd.72.063001

Cited by 44 publications

(62 citation statements)

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“…It is also worth studying possible self-interaction effects in the phenomenology of SN 1987A neutrino events [55][56][57] and of the diffuse supernova neutrino background spectrum [58,59]. Further analytical and numerical developments may require to solve the neutrino evolution equations in the complete 3ν flavor scenario, where new effects associated to the "solar" δm 2 can occur; a recent example has been worked out in [60].…”

Section: Conclusion and Prospectsmentioning

confidence: 99%

Collective neutrino flavor transitions in supernovae and the role of trajectory averaging

Fogli

Lisi

Marrone

et al. 2007

J. Cosmol. Astropart. Phys.

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273

397

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Abstract. Non-linear effects on supernova neutrino oscillations, associated with neutrino-neutrino interactions, are known to induce collective flavor transformations near the supernova core for θ 13 = 0. In scenarios with very shallow electron density profiles, these transformations have been shown to couple with ordinary matter effects, jointly producing spectral distortions both in normal and inverted hierarchy. In this work we consider a complementary scenario, characterized by higher electron density, as indicated by shock-wave simulations during a few seconds after bounce. In this case, early collective flavor transitions are decoupled from later, ordinary matter effects. Moreover, such transitions become more amenable to both numerical computations and analytical interpretations in inverted hierarchy, while they basically vanish in normal hierarchy. We numerically evolve the neutrino density matrix in the region relevant for self-interaction effects, using thermal spectra and a representative value sin 2 θ 13 = 10 −4 . In the approximation of averaged intersection angle between neutrino trajectories, our simulations neatly show the collective phenomena of synchronization, bipolar oscillations, and spectral split, with analytically understandable features, as recently discussed in the literature. In the more realistic (but computationally demanding) case of non-averaged neutrino trajectories, our simulations do not show new significant qualitative features, apart from the smearing of "fine structures" such as bipolar nutations. Our results seem to suggest that, at least for non-shallow matter density profiles, averaging over neutrino trajectories plays a minor role in the final outcome. In this case, the swap of ν e and ν µ,τ spectra above a critical energy may represent an unmistakable signature of the inverted neutrino hierarchy, especially for θ 13 small enough to render further (ordinary or even turbulent) matter effects irrelevant.PACS numbers: 14.60. Pq, 13.15.+g, 97.60.Bw Collective neutrino flavor transitions in supernovae and the role of trajectory averaging 2

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Section: Conclusion and Prospectsmentioning

confidence: 99%

Collective neutrino flavor transitions in supernovae and the role of trajectory averaging

Fogli

Lisi

Marrone

et al. 2007

J. Cosmol. Astropart. Phys.

Self Cite

273

397

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“…The last nearby supernova, SN 1987A, occurred in the Large Magellanic Cloud at 50 kpc, and ≃ 20 neutrinos were detected [3] preceding the optical supernova, confirming our basic understanding of the explosion [4]. However, even taking into account the small statistics, the fitted ranges for the time-integrated luminosity and average energy are perplexing, showing clear discrepancies among the experimental detections and theory [5,6]. A Milky Way supernova would yield many events in present detectors, but the expected supernova rate is only ∼ 3 per century.…”

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confidence: 92%

“…Beyond the two supernova neutrino emission parameters used here, there is also the question of the spectrum shape, and whether it is distorted from thermal by being "pinched" or "anti-pinched" [6]. The SK energy threshold of 18 MeV is used in Ref.…”

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Direct measurement of supernova neutrino emission parameters with a gadolinium-enhanced Super-Kamiokande detector

2006

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The time-integrated luminosity and average energy of the neutrino emission spectrum are essential diagnostics of core-collapse supernovae. The SN 1987A electron antineutrino observations by the Kamiokande-II and IMB detectors are only roughly consistent with each other and theory. Using new measurements of the star formation rate history, we reinterpret the Super-Kamiokande upper bound on the electron antineutrino flux from all past supernovae as an excluded region in neutrino emission parameter space. A gadolinium-enhanced Super-Kamiokande should be able to jointly measure these parameters, and a future megaton-scale detector would enable precision studies.PACS numbers: 97.60. Bw, 98.70.Vc, 95.85.Ry, 14.60.Pq When a massive star dies, its core collapses and rebounds, producing an outgoing shock wave that should eject the stellar envelope, causing the optical supernova, and leaving behind a neutron star remnant. However, in simulations, the shock wave stalls, leading to the whole star collapsing into a black hole, failing to produce an optical supernova or spread its heavy-element yields [1]. Since the required explosion energy is only ∼ 1% of the emergent neutrino energy, a full accounting of the neutrino emission is essential for understanding supernovae. Further, in the Bethe-Wilson delayed explosion model, the neutrinos revive the shock [2]. Resolution of the supernova problem would also have profound implications for the history of stellar evolution and nucleosynthesis.The weak interactions of neutrinos, which allow them to reveal the dynamics deep within the exploding star, also make their detection challenging. The last nearby supernova, SN 1987A, occurred in the Large Magellanic Cloud at 50 kpc, and ≃ 20 neutrinos were detected [3] preceding the optical supernova, confirming our basic understanding of the explosion [4]. However, even taking into account the small statistics, the fitted ranges for the time-integrated luminosity and average energy are perplexing, showing clear discrepancies among the experimental detections and theory [5,6]. A Milky Way supernova would yield many events in present detectors, but the expected supernova rate is only ∼ 3 per century. We have shown that with proposed megaton-scale detectors, it will be possible to build up the spectrum by detecting neutrinos one or two at a time from supernovae within 10 Mpc, at a rate as large as ∼ 1 neutrino per year [7].Here we propose a new approach, which could begin immediately, if the existing Super-Kamiokande (SK) detector were modified by the addition of gadolinium to greatly reduce backgrounds, as proposed by Beacom and Vagins [8,9]. We consider the spectrum of the Diffuse Supernova Neutrino Background (DSNB) [10,11,12,13] as the observable. The DSNB predictions depend on the redshift evolution of the supernova rate, which is separately measurable and increasingly well known, and the neutrino emission per supernova, the object of our study. While the received neutrino spectrum will be redshifted, it will have relatively high stat...

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“…Very crudely the above picture was already confirmed by the observation of the 1987a SN neutrinos. Clearly, the details of the observed spectra shows some puzzling features [31,32,33,34] which call for more data. We expect that in the future substantial theoretical and experimental progress will be made 5 to further improve the understanding of the emitted neutrino spectra.…”

Section: A Present Knowledge Of the Sn Ratementioning

confidence: 99%

Probing Dark Energy via Neutrino and Supernova Observatories

Hall¹,

Murayama²,

Papucci³

et al. 2006

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A novel method for extracting cosmological evolution parameters is proposed, using a probe other than light: future observations of the diffuse anti-neutrino flux emitted from core-collapse supernovae (SNe), combined with the SN rate extracted from future SN surveys. The relic SN neutrino differential flux can be extracted by using future neutrino detectors such as Gadoliniumenriched, megaton, water detectors or 100-kiloton detectors of liquid Argon or liquid scintillator.The core-collapse SN rate can be reconstructed from direct observation of SN explosions using future precision observatories. Our method, by itself, cannot compete with the accuracy of the optical-based measurements but may serve as an important consistency check as well as a source of complementary information. The proposal does not require construction of a dedicated experiment, but rather relies on future experiments proposed for other purposes.

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Analysis of the SN 1987A neutrinos with a flexible spectral shape

Cited by 44 publications

References 39 publications

Collective neutrino flavor transitions in supernovae and the role of trajectory averaging

Collective neutrino flavor transitions in supernovae and the role of trajectory averaging

Direct measurement of supernova neutrino emission parameters with a gadolinium-enhanced Super-Kamiokande detector

Probing Dark Energy via Neutrino and Supernova Observatories

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