Experimental data and background Monte Carlo comparisons

These are the comparisons presented by John Kim at the ICRC in August of 1999. 81 days of live-time of the 1997 experimental data is used with the Swedish filter. The effective time of the background Monte Carlo is $\sim$5 days. Table 11 lists the optimized cut selection for version 1 of the point source anslysis. The cut selections shown are version 1 of the optimized cuts. This table shows that the passing rates agree between background Monte Carlo and data for most of the variables, except for the number of direct hits (both ndir(-15:25ns) and ndir(-15:75ns)). The lack of complete agreement has motivated further work to improve the detector simulation.

 

Table 11: Efficiencies for cuts in the first version of point source analysis.

	Criteria	Description	Data	MC(Sig)	MC(Bg)
0	Swedish filter	multi-variate filter	0.09	0.431	0.063
1	zenith(2)>100	Zenith angle of max likelihood fit	0.219	0.531	0.212
2	ndir(-15:25ns)$\geq$5	Number of direct hits (strict)	0.010	0.578	0.018
3	zenith(1)>105	Zenith angle of line fit	0.656	0.939	0.668
4	ndir(-15:75ns)$\geq$10	Number of direct hits (loose)	0.179	0.818	0.062
5	ldir(-15:25ns)>80m	Projected length of direct hits	0.137	0.845	0.155
6	jkrchi(2)<8	Likelihood parameter of the max likelihood fit	0.752	0.977	0.656
7	jkrchi(3)<4	Likelihood parameter of the energy fit	0.138	0.876	0.167

The following figures (figure 36, 37, and 38) show the signal Monte Carlo distribution and distributions of the experimental data and background Monte Carlo for each variable shown in table 11. The experimental data is $\sim$80 days of the 1997 data set and the background Monte Carlo shown has of an effective live-time of $\sim$5 days. The Monte Carlo distributions have been scaled to the live-time of the data, 81 days. Both the Monte Carlo and the experimental data have passed through the Swedish filter and two quality cuts, ndirb(2)$\geq$5 and zenith(2)><>100.

    

Figure 36: number of direct hits distribution.
Figure 37: likelihood parameter of the maximum likelihood fit and the energy fit.

  

Figure 38: (left) The project length of direct hits in meters and (right) the zenith angle on the line fit in degrees.