Mohamad-Ziad Charif - Antares

Figure 6.15: Comparison between the estimated background given by scrambleddata for the single line events and multi line events in the direction of the Sun as afunction of ∆(θ) and ∆(Ψ) for the same χ 2 cut (1.6).6.4.2.1 Data Monte Carlo comparisonThe pre-analysis quality cuts that we apply on BBFit variables are essentially thesame as in the multi-line analysis, with small differences:1. tchi2 < bchi2.2. nlines = 13. cos(θ) > 0 .4. cos(θ) ≠ 1 .For items (1), and (3) are just the standard pre-analysis cuts that we apply. Asfor (2) it is obvious that we need events that are reconstructed with one singleline. For (4) it is a cut that allows us to remove a significant number of badlyreconstructed atmospheric muons before even starting the analysis.Events with cos(θ) = 1 are events that are reconstructed as exactly vertical, so cut(4) is applied because if we take a look at the estimated number of atmosphericmuons with cos(θ) = 1 we find it to be at least four orders of magnitude higherthan the estimated number of atmospheric neutrinos (figure 6.16), additionallythe estimated number of dark matter events is 0. So this cut allows us to lowersignificantly our background without affecting the signal at all.124