Decoupling supernova and neutrino oscillation physics with LAr TPC detectors

Core collapse supernovae are a huge source of all flavor neutrinos. The flavor composition, energy spectrum and time structure of the neutrino burst from a galactic supernova can provide information about the explosion mechanism and the mechanisms of proto neutron star cooling. Such data can also give information about the intrinsic properties of the neutrino such as flavor oscillations. One important question is to understand to which extend can the supernova and the neutrino physics be decoupled in the observation of a single supernova. On one hand, the understanding of the supernova explosion mechanism is still plagued by uncertainties which have an impact on the precision with which one can predict time, energy and flavor-dependent neutrino fluxes. On the other hand, the neutrino mixing properties are not fully known, since the type of mass hierarchy and the value of the θ13 angle are unknown, and in fact large uncertainty still exists on the prediction of the actual effect of neutrino oscillations in the event of a supernova explosion. In this paper we discuss the possibility to probe the neutrino mixing angle θ13 and the type of mass hierarchy from the detection of supernova neutrinos with a liquid argon TPC detector. Moreover, describing the supernova neutrino emission by a set of five parameters (average energy of the different neutrino flavors, their relative luminosity and the total supernova binding energy), we quantitatively study how it is possible to constrain these parameters. A characteristic feature of the liquid argon TPC is the accessibility to four independent detection channels ( (1) elastic scattering off electrons, (2) charged neutrino and (3) antineutrino and (4) neutral currents on argon nuclei) which have different sensitivities to electron-neutrino, anti-electron-neutrino and other neutrino flavors (muon and tau (anti)neutrinos). This allows to over-constrain the five supernova and the flavor mixing parameters and to some extent disentangle neutrino from supernova physics. Numerically, we find that a very massive liquid argon detector (O(100 kton)) is needed to perform accurate measurements of these parameters, specially in supernova scenarios where the average energies of electron and non-electron neutrinos are similar (almost degenerate neutrinos) or if no information about the θ13 mixing angle and type of mass hierarchy is available.