Study of the effect of neutrino oscillations on the supernova neutrino signal in the LVD detector

Abstract

The LVD detector, located in the INFN Gran Sasso National Laboratory (Italy), studies supernova neutrinos through the interactions with protons and carbon nuclei in the liquid scintillator and interactions with the iron nuclei of the support structure. We investigate the effect of neutrino oscillations in the signal expected in the LVD detector. The MSW effect has been studied in detail for neutrinos travelling through the collapsing star and the Earth. We show that the expected number of events and their energy spectrum are sensitive to the oscillation parameters, in particular to the mass hierarchy and the value of θ 13 , presently unknown. Finally we discuss the astrophysical uncertainties, showing their importance and comparing it with the effect of neutrino oscillations on the expected signal.

Neutrinos from type Ia supernovae: The deflagration-to-detonation transition scenario

“…The important point is that the 10 MeV peak is mostly caused by electron capture on copper. In particular, the isotopes 57 Cu, 53 Co, and 51 Fe are responsible for the 10 MeV peak. The 10 MeV peak is a very interesting feature because if it is ever experimentally seen it could give information about the nuclear composition of the SN in a neutrino signal.…”

“…Neutrinos from a core-collapse supernova were observed in 1987 [48][49][50] and, despite its paucity, the signal was fully exploited in order to extract competitive limits on multiple neutrino properties as well as testing the basic paradigm of core-collapse. Should the next burst from a core-collapse supernova arrive tomorrow, many more events will be recorded for the very simple reason that, compared to the size and scale of detectors operating in 1987, present-day detectors such as Baksan [51], Super-Kamiokande [52], LVD [53], KamLAND [54], MiniBOONE [55], Borexino [56], Daya Bay [57] and the dedicated supernova burst detector HALO [58] are much larger and/or more sensitive to lower energies or to a broader set of channels. The burst would also be recorded in IceCube [59] and Antares [60] but with no event-by-event energy resolution.…”

Large-scale calculations of supernova neutrino-induced reactions inZ=8–82 target nuclei

“…Modeling neutrino-nucleus interactions is also important in view of the current research and development of neutrino detectors, e.g., for supernova and solar neutrinos, neutrinos produced in laboratories, and geoneutrinos. The ongoing and planned neutrino detector facilities involve a variety of target materials, induced reactions and scientific objectives, e.g., MOON [14], MiniBooNE [15], MINOS [16], SNO+ [17], OPERA [18], LVD (Large Volume Detector) [19], ORLaND experiment proposal at the Spallation Neutron Source (SNS) [20], NOvA neutrino experiment [21], Daya Bay reactor neutrino experiment [22], etc. There is also interesting concept of β beams for the production of neutrinos by using β decay of boosted radioactive ions [23,24].…”

Neutrino bursts from gravitational stellar collapses with LVD

“…Besides interactions with free protons LVD is also sensitive to charged current interactions with carbon and iron nuclei through: -ν e 12 C, 12 N e − , (physical threshold E ν e >17.3 MeV) observed through two signals: the prompt one due to the e − (E d E ν e −17.3 MeV) followed by the signal from the β + decay of 12 N (mean life τ =15.9 ms); -ν e 12 C, 12 B e + , (physical threshold Eν e >14.4 MeV) observed through two signals: the prompt one due to the e + (E d Eν e −14.4 MeV+2m e c 2 ) followed by the signal from the β − decay of 12 B (mean life τ =29.4 ms); -ν e 56 Fe, 56 Co e − , where the mass difference between the nuclei is m n =m Co n −m Fe n =4.055 MeV, and the first Co allowed state at 3.589 MeV; the efficiency for electron and gammas, also produced in the interaction, to reach the scintillator with energy higher than E H has been simulated (see Agafonova et al, 2007); on average, the detectable electron energy is E d 0.45×E ν .…”

“…Assuming a model for the neutrino emission and propagation, the detector sensitivity can be expressed in terms of source distance (or emitted neutrino flux). In particular we adopt the following conservative values for the astrophysical parameters of SN1987A (Costantini et al, 2004(Costantini et al, , 2007: averageν e energy <Eν e >=14 MeV; total radiated energy E b =2.4·10 53 erg, assuming energy equipartition; average non-electron neutrino energy 10% higher thanν e (Keil et al, 2003), and concerning neutrino oscillations (see Agafonova et al, 2007, for a discussion), we consider normal mass hierarchy. We calculate the number of inverse beta decay signals expected from a SN1987A-like event occurring at different distances, for E cut =7 and E cut =10 MeV.…”