Supernova Neutrino Detection Research Articles

Detection of Supernova Neutrinos

Prospects for the future detection of supernova neutrinos are discussed, with particular emphasis on water Cherenkov detectors. A novel proposed modification to the Super–Kamiokande experiment designed to significantly enhance its supernova detection capabilities is discussed. Plans and progress towards realizing this new technology are described, as are some of the varied physics benefits it would provide.

Ideas for future liquid Argon detectors

We outline a strategy for future experiments on neutrino and astroparticle physics based on the use, at different detector mass scales (100 ton and 100 kton), of the liquid Argon Time Projection Chamber (LAr TPC) technique. The LAr TPC technology has great potentials for both cases with large degree of interplay between the two applications and a strong synergy. The ICARUS R&D programme has demonstrated that the technology is mature and that one can built a large ($\sim$ 1 kton) LAr TPC. We believe that one can conceive and design a very large mass LAr TPC with a mass of 100 kton by employing a monolithic technology based on the use of industrial, large volume cryogenic tankers developed by the petro-chemical industry. We show a potential implementation of a large LAr TPC detector. Such a detector would be an ideal match for a Superbeam, Betabeam or Neutrino Factory, covering a broad physics program that could include the detection of atmospheric, solar and supernova neutrinos, and search for proton decays, in addition to the rich accelerator neutrino physics program. In parallel, physics is calling for another application of the LAr TPC technique at the level of 100 ton mass, for low energy neutrino physics and for use as a near station setup in future long baseline neutrino facilities. We present here the main physics objectives and outline the conceptual design of such a detector.

Decoupling supernova and neutrino oscillation physics with LAr TPC detectors

Core collapse supernovae are a huge source of all flavour neutrinos. The flavourcomposition, energy spectrum and time structure of the neutrino burst from a galacticsupernova can provide information about the explosion mechanism and the mechanisms ofproto neutron star cooling. Such data can also give information about the intrinsicproperties of the neutrino such as flavour oscillations. One important question isto understand to what extent the supernova and the neutrino physics can bedecoupled in the observation of a single supernova. On one hand, the understandingof the supernova explosion mechanism is still plagued by uncertainties whichhave an impact on the precision with which one can predict time-, energy- andflavour-dependent neutrino fluxes. On the other hand, the neutrino mixing propertiesare not fully known, since the type of mass hierarchy and the value of theθ13 angle are unknown, and in fact large uncertainty still exists on the prediction ofthe actual effect of neutrino oscillations in the event of a supernova explosion.In this paper we discuss the possibility of probing the neutrino mixing angleθ13 and the type of mass hierarchy from the detection of supernova neutrinos with a liquidargon TPC detector. Moreover, describing the supernova neutrino emission by a set of fiveparameters (average energy of the different neutrino flavours, their relative luminosity andthe total supernova binding energy), we quantitatively study how it is possible to constrainthese parameters. A characteristic feature of the liquid argon TPC is the accessibility tofour independent detection channels ((1) elastic scattering off electrons, (2) chargedneutrino and (3) antineutrino and (4) neutral currents on argon nuclei) which have differentsensitivities to electron neutrino, anti-electron neutrino and other neutrino flavours (muonand tau (anti)neutrinos). This allows us to over-constrain the five supernova andthe flavour mixing parameters and to some extent disentangle neutrino fromsupernova physics. Numerically, we find that a very massive liquid argon detector(O(100 kton)) is needed to perform accurate measurements of these parameters, speciallyin supernova scenarios where the average energies of electron and non-electronneutrinos are similar (almost degenerate neutrinos) or if no information about theθ13 mixing angle and type of mass hierarchy is available.

LOW ENERGY NEUTRINO PHYSICS AFTER SNO AND KamLAND

In the recent years important discoveries in the field of low energy neutrino physics (Eν in the ≈ MeV range) have been achieved. Results of the solar neutrino experiment SNO show clearly flavor transitions from νe to νμ,τ. In addition, the long standing solar neutrino problem is basically solved. With KamLAND, an experiment measuring neutrinos emitted from nuclear reactors at large distances, evidence for neutrino oscillations has been found. The values for the oscillation parameters, amplitude and phase, have been restricted. In this paper the potential of future projects in low energy neutrino physics is discussed. This encompasses future solar and reactor experiments as well as the direct search for neutrino masses. Finally the potential of a large liquid scintillator detector in an underground laboratory for supernova neutrino detection, solar neutrino detection, and the search for proton decay p→K+ν is discussed.

Supernova neutrino-nucleus reactions

Neutrino-nucleus reactions play important roles in many astrophysical scenarios. This manuscript reviews several recent applications, including core-collapse supernovae, neutrino nucleosynthesis and supernova neutrino detectors, and discusses how neutrino-nucleus cross sections are derived in the absence of direct experimental data.

Supernova neutrino-nucleus reactions

Neutrino-nucleus reactions play important roles in many astrophysical scenarios. This manuscript reviews several recent applications, including core-collapse supernovae, neutrino nucleosynthesis and supernova neutrino detectors, and discusses how neutrino-nucleus cross sections are derived in the absence of direct experimental data.

Supernova neutrino-nucleus reactions

Neutrino-nucleus reactions play important roles in many astrophysical scenarios. This manuscript reviews several recent applications, including core-collapse supernovae, neutrino nucleosynthesis and supernova neutrino detectors, and discusses how neutrino-nucleus cross sections are derived in the absence of direct experimental data.

Observing nucleon decay in lead perchlorate

Lead perchlorate, part of the OMNIS supernova neutrino detector, contains two nuclei, 208Pb and 35Cl, that might be used to study nucleon decay. Both would produce signatures that will make them especially useful for studying less-well-studied neutron decay modes, e.g., those in which only neutrinos are emitted.

Neutrino–nucleus reactions and nuclear structure

The methods used in the evaluation of the neutrino–nucleus cross section are reviewed. Results are shown for a variety of targets of practical importance. Many of the described reactions are accessible in future experiments with neutrino sources from the pion and muon decays at rest, which might be available at the neutron spallation facilities. Detailed comparison between the experimental and theoretical results would establish benchmarks needed for verification and/or parameter adjustment of the nuclear models. Having a reliable tool for such calculation is of great importance in a variety of applications, e.g. the neutrino oscillation studies, detection of supernova neutrinos, description of the neutrino transport in supernovae and description of the r-process nucleosynthesis.

Supernova science at spallation neutron sources

New facilities to measure neutrino–nucleus cross sections, such as those possible in conjunction with spallation neutron sources, could provide an experimental foundation for the many neutrino–nucleus weak interaction rates needed in supernova models. This would enable more realistic supernova models and provide a greatly improved ability to understand the physics fundamental to supernovae by comparison of these models with detailed observations. Charged- and neutral-current neutrino interactions on nuclei in the stellar core play a central role in supernova dynamics and nucleosynthesis as well as being important for supernova neutrino detection. Measurements of these reactions on judiciously chosen targets would provide an invaluable test of the complex theoretical models used to compute the large number of neutrino–nucleus cross sections that are needed.

Supernovae and neutrinos

A long-standing problem in supernova physics is how to measure the total energy and temperature of ν μ , ν τ , ν μ , and ν τ . While of the highest importance, this is very difficult because these flavors only have neutral-current detector interactions. We propose that neutrino-proton elastic scattering, ν + p → ν + p, can be used for the detection of supernova neutrinos in scintillator detectors. It should be emphasized immediately that the dominant signal is on free protons. Though the proton recoil kinetic energy spectrum is soft, with T p ≌ 2E ν 2 M p , and the scintillation light output from slow, heavily ionizing protons is quenched, the yield above a realistic threshold is nearly as large as that from ν e + p → e ++n . In addition, the measured proton spectrum is related to the incident neutrino spectrum. The ability to detect this signal would give detectors like KamLAND and Borexino a crucial and unique role in the quest to detect supernova neutrinos. These results are now published: J. F. Beacom, W. M. Farr and P. Vogel, Phys. Rev. D 66, 033001 (2002) [arXiv:hep-ph/0205220], the details are given there [1].

What can be learned with a lead-based supernova-neutrino detector?

We examine the prospects for using lead as a supernova-neutrino detector by considering the spectrum of electrons produced, and the number of one- and two-neutron events. We show that the electron energy spectrum from charged-current reactions can be used to extract information about the high-temperature component of the neutrino spectrum. Some degree of electron neutrino oscillation is expected in the supernova envelope. We examine the prospects for untangling the signatures of various oscillation scenarios, including, e.g. normal or inverted hierarchies, and different values for the small mixing angle, theta_13.

Cross sections for neutral-current neutrino scattering on208Pb

We present continuum random phase approximation (CRPA) calculations for neutral-current neutrino scattering off ${}^{208}\mathrm{Pb}.$ These reactions are of interest for the terrestrial detection of supernova neutrinos. We fold the computed cross sections with a Fermi-Dirac distribution to obtain information about these processes and examine the dependence of the response on the spectrum parameters. The experimental interest in neutron knockout induced by neutrino interactions on ${}^{208}\mathrm{Pb}$ motivated an analysis of the CRPA branching ratios and single-particle knockout channels. We investigate the role of the single-particle wave functions and the residual interaction for the response. We compare our cross sections with previous work.

Detection of supernova neutrinos by neutrino-proton elastic scattering

We propose that neutrino-proton elastic scattering, $\ensuremath{\nu}+\stackrel{\ensuremath{\rightarrow}}{p}\ensuremath{\nu}+p,$ can be used for the detection of supernova neutrinos in scintillator detectors. Though the proton recoil kinetic energy spectrum is soft, with ${T}_{p}\ensuremath{\simeq}{2E}_{\ensuremath{\nu}}^{2}{/M}_{p},$ and the scintillation light output from slow, heavily ionizing protons is quenched, the yield above a realistic threshold is nearly as large as that from ${\overline{\ensuremath{\nu}}}_{e}+\stackrel{\ensuremath{\rightarrow}}{p}{e}^{+}+n.$ In addition, the measured proton spectrum is related to the incident neutrino spectrum, which solves a long-standing problem of how to separately measure the total energy and temperature of ${\ensuremath{\nu}}_{\ensuremath{\mu}},$ ${\ensuremath{\nu}}_{\ensuremath{\tau}},$ ${\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}},$ and ${\overline{\ensuremath{\nu}}}_{\ensuremath{\tau}}.$ The ability to detect this signal would give detectors like KamLAND and Borexino a crucial and unique role in the quest to detect supernova neutrinos.

Potential for supernova neutrino detection in MiniBooNE

The MiniBooNE detector at Fermilab is designed to search for ${\ensuremath{\nu}}_{\ensuremath{\mu}}\ensuremath{\rightarrow}{\ensuremath{\nu}}_{e}$ oscillation appearance at ${E}_{\ensuremath{\nu}}\ensuremath{\sim}1 \mathrm{GeV}$ and to make a decisive test of the LSND signal. The main detector (inside a veto shield) is a spherical volume containing 0.680 ktons of mineral oil. This inner volume, viewed by 1280 phototubes, is primarily a \ifmmode \check{C}\else \v{C}\fi{}erenkov medium, as the scintillation yield is low. The entire detector is under a 3 m earth overburden. Though the detector is not optimized for low-energy (tens of MeV) events, and the cosmic-ray muon rate is high (10 kHz), we show that MiniBooNE can function as a useful supernova neutrino detector. Simple trigger-level cuts can greatly reduce the backgrounds due to cosmic-ray muons. For a canonical Galactic supernova at 10 kpc, about 190 supernova ${\overline{\ensuremath{\nu}}}_{e}+\stackrel{\ensuremath{\rightarrow}}{p}{e}^{+}+n$ events would be detected. By adding MiniBooNE to the international network of supernova detectors, the possibility of a supernova being missed would be reduced. Additionally, the paths of the supernova neutrinos through Earth will be different for MiniBooNE and other detectors, thus allowing tests of matter-affected mixing effects on the neutrino signal.

Supernova-neutrino detection and the 208Pb(ν, ν') 208Pb∗ cross section

We calculate cross sections for the neutral current neutrino-scattering reaction 208Pb(ν,ν') 208Pb∗ within a continuum RPA (CRPA) approach. As these reactions are important for the detection of supernova-neutrinos, we study the cross section as a function of the temperature of the neutrino spectrum.

Is the LMA solar-neutrino solution ruled out by SN1987A data?

The development of new supernova neutrino detectors relies on the expected hard energy spectrum of the ν μ and ν τ emitted in the supernova. We show that SN1987A was sensitive to the large mixing angle (LMA) and “just so” solution to the solar neutrino problem. We review the previous analysis of the SN1987A data and propose a new analysis. The results of this analysis strongly disfavor the LMA solution, provided the ν μ and ν τ are hard as predicted

Effect of flavour oscillations on the detection ofsupernova neutrinos

Neutrinos and antineutrinos of all three flavours are emitted during the post-bounce phase of a core-collapse supernova with having average energies more than that of They can be detected by the new earthbound detectors like SNO and Super-Kamiokande which are sensitive to neutrinos of all three flavours. In this letter we consider the effect of flavour oscillations on the neutrino flux and their expected number of events at the detector. We do a three-generation analysis and for the mass and mixing schemes we first consider the threefold maximal mixing model consistent with the solar and the atmospheric neutrino data and next a scenario with one m2~10-11 eV2 (solar range) and the other m2~10-18 eV2, for which the oscillation length is of the order of the supernova distance. In both these scenarios there are no matter effects in the resultant neutrino spectrum and one is concerned with vacuum oscillations. We find that though neutrino oscillations result in a depletion in the number of e and coming from the supernova, the actual signals at the detectors are appreciable enhanced as the e and energy spectra become harder.

Real time supernova neutrino burst detection with MACRO

Abstract The MACRO experiment has been running as a supernova neutrino detector since 1989 and is sensitive to the whole galaxy since the beginning of 1992. A galactic supernova would produce some hundreds of ν e events in the detector. We describe our stellar gravitational collapse online monitors and alarm system, and present the results of a search for neutrino bursts from supernovae during a period of 1.5 yr.

OMNIS—an improved low-cost detector to measure mass and mixing of mu/tau neutrinos from a Galactic supernova

Abstract OMNIS is an observatory for multiflavour interactions from Galactic supernovae. It has evolved from the Supernova Neutrino Burst Observatory (SNBO) proposed by Cline et al., based on the detection of the neutrinos by neutral current nuclear excitation in natural rock. This would result in the emission of neutrons, which could be captured by counters embedded in the rock. This scheme would be sensitive principally to the higher temperature μ and τ neutrinos and would allow time-of-flight measurement of neutrino mass if in the cosmologically interesting range 10–100 eV. The present paper proposes a new neutron detection arrangement which improves detection efficiency and reduces cost by a factor ∼ 30, allowing the time profile of over 2000 ν μτ events to be recorded with only 200 tons scintillator. This new scheme represents the optimum configuration for a natural underground rock target. A Galactic supernova signal would be a factor 10–30 above neutron background (from cosmic ray muons and alpha activity) in sites with depth > 500 mwe. Another major improvement results by supplementing the rock with more favourable target elements such as iron or lead, giving sensitivity to all three neutrino types and mixing between these. Some calculations are included on the speculative possibility of extra-Galactic supernova neutrino detection using this principle.