IC40 Cascade Analysis
Stephanie Hickford
University of Canterbury
Last updated:

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Stephanie's Homepage Analysis Data CORSIKA Signal Level 2 Trigger (level 0) Pole filter (level 1) Level 2 Level 3 Cut variables Reconstructions Development of cuts Level 4 Cut variables Reconstructions Development of cuts Level 5 Cut variables Development of cuts Level 6 Cut variables Development of cuts Final Sensitivity Remaining events Resolutions Data/Monte Carlo Comparison Excess in COG Level 5 TMVA Summary Of Issues Feature extractor Hit binning bug Good DOM list DOMcalibrator Systematics Ice properties DOM efficiency Cross-section Seasonal variation Unblinding Discussion Diffuse call Analysis call Results Plots Events

Final Sensitivity Figure 1 shows the final energy spectrum after all cut levels, Figure 2 shows the effective area as a function of energy, and Figure 3 shows a comparison of number of events for each cut level with Joanna's IC22 high energy cascade analysis. Figure 1: Reconstructed energy using 4 iteration Credo. Figure 2: Effective area. Figure 3: Comparison of number of events at each cut level to IC22 high energy cascade analysis. The effective livetime is the equivalent amount of unweighted simulation that would required to obtain the same relative error bars as the weighted simulation gives. A detailed description on this calculation can be found in John Kelley and Gary Hill's paper and Michaelangelo D'Agostino's internal report. Figure 4: Effective Livetime plots: a) Standard CORSIKA with MCPrimary_Energy. b) Standard CORSIKA with CredoFit4_Energy. c) Two-component CORSIKA with MCPrimary_Energy. d) Two-component CORSIKA with CredoFit4_Energy. In Figure 5 you will see the n-1 plots for the cut variables in level 6 of the analysis. This is intended to show where the remaining data events lie with respect to the cut boundaries. These boundaries are shown by a black vertical line in each plot. Figure 5: n-1 distributions of cut variables. a) BDT response, b) Energy. Table 1 shows the final number of events for 337.24 days of IC40 detector livetime and Table 2 shows the contribution to the number of atmospheric neutrino events from various models. Below this Table 3 shows the Feldman-Cousins quantites that are used for the sensitivity calculation. The final sensitivty for this analysis is 2.75445 × 10-8 GeVsr-1s-1cm-2 with a central 90% primary energy region of 4.4 to 6.7 in logscale (25.12 TeV to 5011.87 TeV). . Number of Events Experimental data 6.3666 × 10-7Hz × (8093.71hours × 60minutes × 60seconds) = 18.5505 events Single CORSIKA 0 Double CORSIKA 0 Triple CORSIKA 0 Weighted single CORSIKA 0 Weighted double CORSIKA 0 Proton two-component CORSIKA 0 Iron two-component CORSIKA 0 E-2 &nue signal (3.6 × 10-7) 2.80514 × 10-6Hz × (8093.71hours × 60minutes × 60seconds) = 81.1734 events E-2 &nu&mu signal (3.6 × 10-7) 9.76639 × 10-7Hz × (8093.71hours × 60minutes × 60seconds) = 28.4567 events E-2 &nu&tau signal (3.6 × 10-7) 2.65159 × 10-6Hz × (8093.71hours × 60minutes × 60seconds) = 77.2603 events Atmospheric &nue signal (conv. + prompt) 7.83573 × 10-8Hz × (8093.71hours × 60minutes × 60seconds) = 2.2831 events Atmospheric &nu&mu signal (conv. + prompt) 5.59485 × 10-8Hz × (8093.71hours × 60minutes × 60seconds) = 1.6302 events Table 1: Remaining events after all levels of cuts. Model Number of &nue Events Number of &nu&mu Events Bartol 0.641798 events 1.16748 events Sarcevic_std 1.64133 events 0.462709 events Sarcevic_min 0.970059 events 0.269603 events Sarcevic_max 2.0843 events 0.583063 events Naumov_rqpm 2.60818 events 1.57047 events Naumov_qgsm 1.33736 events 1.07329 events Table 2: Various atmospheric neutrino models. Number of signal events 1/3(&nue + &nu&mu + &nu&tau) = 62.4838 events Number of background events CORSIKA + atmoe + atmo&mu = 3.91332 events Number of critical events 18 events Least detectable signal 19.7 events Upper limit (&mu90) 4.78079 events Model rejection factor 0.0765124 Model discovery factor 0.315282 Sensitivity flux (E-2) 2.75445 × 10-8 GeVsr-1s-1cm-2 Discovery flux (E-2) 1.13501 × 10-7 GeVsr-1s-1cm-2 Table 3: Sensitivity. Remaining events Data events: There are 2 remaining burn sample events: Event details Run: 110860 Date: 18th April 2008, 9:56:42 am Energy: 29.13 TeV BDT response: 0.2675667 NCh: 88 Zenith: 70.58° Azimuth: 79.14° X vertex: -79.58 metres Y vertex: 322.01 metres Z vertex: 201.82 metres Event details Run: 111780 Date: 16th October 2008, 11:32:47am Energy: 144.20 TeV BDT response: 0.2361462 NCh: 359 Zenith: 72.63° Azimuth: 148.70° X vertex: 378.63 metres Y vertex: 225.91 metres Z vertex: -303.59 metres Resolutions Figure 6: Resolution Plots: a) X vertex reconstruction. b) Y vertex reconstruction. c) Z vertex reconstruction. d) Energy reconstruction. e) Zenith direction reconstruction. f) Azimuth direction reconstruction.

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Supervisors: Dr. Jenni Adams and Dr. Suruj Seunarine
email: Stephanie Hickford