Simulation of the LSD Response to the Neutrino Burst from SN 1987A

TL;DR

This study uses Geant4 simulations to analyze the LSD detector's response to the SN 1987A neutrino burst, examining different models and hypotheses to interpret the observed signals.

Contribution

It presents a comprehensive simulation of the LSD response considering various neutrino flux models and tests the hypothesis of environmental neutron flux causing the signals.

Findings

Simulations can match either pulse count or energy spectrum, but not both simultaneously.

Neutron flux from surrounding granite does not explain the LSD signals.

Different neutrino flux models produce varying detector responses.

Abstract

Using the Geant4 code, we have performed a full-scale simulation of the LSD response to the neutrino burst from SN1987A. The neutrino flux parameters were chosen according to one of the models: the standard collapse model or the rotational supernova explosion model. We showed that, depending on the chosen parameters, one can either obtain the required number of pulses in the detector or reproduce their energy spectrum, but not both together. The interaction of neutrino radiation both with LSD itself and with the material of the surrounding soil was taken into account in our simulation. We also explored the hypothesis that the entire unique LSD signal at 2:52 UT was produced by neutron fluxes from the surrounding granite. However, this hypothesis was not confirmed by our simulation. The results obtained provide a rich material for possible interpretations.