Data release: Atmospheric neutrino oscillation analysis with neutron tagging and an expanded fiducial volume in Super-Kamiokande I-V

// ----------------------------------------------------------------------------//// Super-Kamiokande I-V Atmospheric Neutrino Data Release// Associated publication: "Atmospheric neutrino oscillation analysis with// neutron tagging and an expanded fiducial volume in Super-Kamiokande I-V"// Corresponding author: Roger Wendell, <[e-mail]>// DOI: 10.5281/zenodo.8401262//// ---------------------------------------------------------------------------- // Changelog, v2 [2026-11-03] Corrections to the MC summary statistics and bin definitions in `bins/`, andtrimmed chi2 tables. Data counts are unchanged. - MC counts include events previously omitted from some bins (+0.09% total, at most ~1% in any bin). MCTotal now equals the sum over neutrino types.- MC averages, RMS values and quantiles are recomputed. Energy quantiles no longer carry a bias from linear binning, which mainly affected the PC and Upmu samples.- Three bins had an incorrect upper CosZ edge (sk1-5_upmu_thru_*: now 0.0; sk4-5_fc_subgev_1ring_numubarlike, LogP 3.0-3.2: now 1.0). Bin edges in the text file are now given to four decimal places.- Removed `sk_2023_MCTotal.txt` from `normal/` and `inverted/`; these duplicated `sk_2023_MCTotalNO.txt` and `sk_2023_MCTotalIO.txt`.- chi2 listings now start at Delta m^2 = 1.6e-3 eV^2. Grid nodes at 1.0-1.5e-3 (theta13-constrained) and 1.2-1.5e-3 (theta13-free) were removed. These included non-converged fits, previously listed as inf, and otherwise had Delta chi^2 values above 29 throughout. All remaining values are unchanged. Overview This data release accompanies the publication "Atmospheric neutrino oscillationanalysis with neutron tagging and an expanded fiducial volume inSuper-Kamiokande I-V." The information provided is divided into twosub-directories: - bins: Contains data & MC counts in each analysis bin for different oscillation configurations - chi2: Contains listings of chisquare values at each point in the oscillation parameter space scanned for the analyses described in the accompanying publication Bin Information This section describes the provided bin information. The `bins/` subdirectoryincludes a ROOT file which contains binning information, data, and MC countsand MC summary statistics in each bin in the form of several ROOT trees. Thecontents of the ROOT file are also provided as text files within the samesubdirectory. There are 930 bins used for atmospheric neutrino data in the analysis. EachROOT tree and text file contains sequential listing of information for each ofthe 930 bins, i.e. the first entry or line of each tree and text filecorresponds to the first bin, and so on. DISCLAIMER: The data and MC counts and summary statistics provided are notexpected to be sufficient to identically reproduce the publication fit results.The publication fit results rely on response functions of the bins tovariations in the systematic uncertainty parameters which are not included inthis release. Additionally, the MC oscillation probabilities used in thepublication were computed individually for each MC event and are not possibleto reproduce exactly using the binned event information provided with thisrelease. Bin Definitions The ROOT file contains a `BinInfoTree` which lists the sample name associatedwith each bin, and the upper and lower bin edges of the 2D binning scheme usedto bin atmospheric neutrino events. The sample names describe the selectionsused to place events in each bin, e.g. "subgev" and "multigev" for sub-GeV andmulti-GeV events, respectively. Since data from the different SK phases aredivided into different analysis samples, each sample name also lists the rangeof SK phases included in the same, e.g. sk1-5 for SK I, SK II, SK III, SK IV,and SK V, or sk4-5 for SK IV and SK V only. The contents of this tree are alsolisted in the `bins/sk_2023_BinInfo.txt` file. Data Counts Observed atmospheric neutrino data counts in each bin are listed in the`DataTree` within the ROOT file. The contents of this tree are also listed inthe `bins/sk_2023_Data.txt` file. MC Counts and Summary Statistics MC counts and summary statistics of the true MC energies and directions areprovided for each true neutrino type in the ROOT trees named `MC*Tree`. Theinformation is provided for three oscillation configurations: Thetheta13-constrained best-fit oscillation parameters in the normal (NO) andinverted (IO) orderings, and without oscillations (NoOsc). The following summary statistics are provided for both the true neutrinoenergies and directions (cosine zenith angle) of MC events in each bin:Average, RMS, 2.3%, 15.9%, 50%, 84.1%, and 97.7% quantiles. The quantilesapproximately correspond to -2, -1, 0, +1, and +2 sigma deviations from themedian. The ROOT tree MC information is duplicated in the text files found under the`bins/[normal,inverted,unoscillated]` subdirectories, corresponding to the threeoscillation scenarios. Chisquare Information We provide listings of the relative chisquare values with respect to thebest-fit point in each ordering. The listings are provided as text files: Thefirst columns correspond to the oscillation parameters at each grid point,while the final column lists the chisquare value. Chisquare values are providedfor both the theta13-free and theta13-constrained analyses. Adding 5.2283 forthe theta13-free and 5.6905 for the theta13-constrained inverted ordering chi2values place the inverted values with respect to the best fit in the normalordering. The convention used is delta_m^2_{32} for the normal ordering, and|delta_m^2_{31}| for the inverted ordering. ROOT files containing the 1D delta chisquare profiles for delta CP, and 2Ddelta chisquare profiles for allowed values of delta m^2 versus sin2 theta23 at68% and 90% are also provided. There are two ROOT files corresponding to thecontours from the theta13-free and theta13-constrained fits. A ROOT macro which draws the contours is also provided. It can be run using thefollowing command from the chi2 directory: ```> root draw_sk_contours.cc```