Correlation analysis of gravitational waves and neutrino signals to constrain neutrino flavor conversion in core-collapse supernova

Recent multidimensional (multi-D) core-collapse supernova (CCSN) simulations characterize gravitational waves (GWs) and neutrino signals, offering insight into universal properties of CCSN independent of progenitor. Neutrino analysis in real observations, however, will be complicated due to the ambiguity of self-induced neutrino flavor conversion (NFC), which poses an obstacle to extracting detailed physical information. In this paper, we propose a novel approach to place a constraint on NFC from observed quantities of GWs and neutrinos based on correlation analysis from recent, detailed multi-D CCSN simulations. The proposed method can be used even in cases with low significance or no detection of GWs. We also discuss how we can utilize electromagnetic observations to complement the proposed method. Although our proposed method has uncertainties associated with CCSN modeling, the present result will serve as a base for more detailed studies. Reducing the systematic errors involved in CCSN models is a key to success in this multimessenger analysis that needs to be done in collaboration with different theoretical groups.