Model-independent Approach to the Reconstruction of Multiflavor Supernova Neutrino Energy Spectra

The model-independent reconstruction of the energy spectra of (nu) over bar (e), nu(e), and nu(x) (i.e., nu(mu) , nu(tau) , and their antiparticles) from the future observation of a galactic core-collapse supernova (SN) is of crucial importance to understand the microscopic physics of SN explosions. To this end, we propose a practically useful method to combine the multichannel detection of SN neutrinos in a large liquid-scintillator detector (e.g., JUNO), namely, the inverse beta decay (nu) over bar (e) + p -> e(+) + n, the elastic neutrino-proton scattering nu + p -> nu + p and the elastic neutrino-electron scattering nu + e(-) -> nu + e(-) , and reconstruct the energy spectra of (nu) over bar (e), nu(e), and nu(x) by making the best use of the observational data in those three channels. In addition, the neutrino energy spectra from the numerical simulations of the delayed neutrino-driven SN explosions are implemented to demonstrate the robustness of our method. Taking the ordinary matter effects into account, we also show how to extract the initial neutrino energy spectra in the presence of neutrino flavor conversions.