Tragically, it looks like no significant neutrino signal was detected in Super-K from SN 2023ixf – the nearby core collapse supernova that exploded two weeks ago, 6.4 Mpc away in M101.

GCN Circular 33916
Subject: Super-Kamiokande: Neutrino search for SN2023ixf
Date: 2023-06-05T12:30:44Z (10 hours ago)
From:
Yusuke Koshio at Super-Kamiokande
M. Nakahata, Kamioka Observatory, Institute for Cosmic Ray Research,
University of Tokyo, reports on behalf of the Super-Kamiokande collaboration:

Super-Kamiokande, a 50 ktons water Cherenkov imaging detector situated 1000 meters underground in the Kamioka mine, Gifu, Japan, has searched for neutrino signal correlated with SN2023ixf in a time window 2 days before the detection by Oak St. Observatory (2023-05-17 08:45:13 to 2023-05-19 08:45:13), during which Super-Kamiokande took data stably without dead time. In the electron total energy region between 7.0 MeV and 100 MeV within a fiducial volume of 22.5 ktons, no significant signal was observed.

It is not clear from this text if the Super-K team pursued my recommended search strategy which was: Narrow the explosion window down to an hour or less (perhaps as short as 15 minutes?) before unblinding the data and looking for a single suspect neutrino.

The quoted 2-day window is too broad to get a significant signal from a single neutrino, even with modestly good (<1 sr) directional resolution. So over a 2-day window they would have to be looking for a multi-neutrino excess as their signal.

Nonetheless, looking forward to the paper!