1. BBfit v3.2 Hit selection Fit function Amplitude Distance
Angular floor acceptance
J. Brunner
CPPM

2. Hit selection Version 2 Version 3.2 Start from T3
Accept hit if within +/-80(160) nsec in next (next-to-next) floor
Version 3.2
Linear extrapolation from last two hits
Accept hit if within -10,+90 from extrapolated time

3. Version 2

4. Version 3.2

5. Fit Quality Version 2 Version 3
Penalty for bright events, i.e. high energy
Version 3
Modified amplitude-distance term to avoid HE penalty

6. Effective amplitude Artificial saturation at 10 pe introduced
Equalizes ARS responses

7. Effective distance
Avoid pull towards d=0

8. Angular acceptance of OM triplet
Very close to “moon phases”
Different colors refer to different azimuth

9. Fit Quality for upward going tracks
1.29/day
0.78/day
0.70/day
0.005/day
1.22/day
0.01/day
Multi line fit
Version 2
Version 3.2

10. Fit Quality for upward going tracks
0.55/day
0.35/day
0.42/day
0.62/day
0.04/day
0.02/day
Single line fit
Version 2
Version 3.2

11. Brightpoint cut Modified cut, not anymore related to track fit
Example : multiline fit
Cut at 1.7 eliminates further background

12. Number of hits (floors) cut
Single line fit
Multi line fit
Exclude fits with less than 6 floors used in hit
Effective cut against atmospheric muon signal
Negligible loss on neutrinos
Single line: nhit=4 and nhit=5 : important contribution
which is not represented in MC

13. Angular error for zenith angle
Mean values of log of zenith angle difference
Dashed : basic cuts only
Full: Fit quality cut added (see above)
muons
2.0º
0.7º (15%)
Version 2
Version 3.2
Muons and neutrinos equally well reconstructed,
not much improvement with new version

14. Angular error for space angle
Mean values of log of space angle difference
Dashed : basic cuts only
6.5º
3.1º (15%)
Version 2
Version 3.2
Space angle error dominated by azimuth error
Most events on 2 lines reconstructed
Mirror solution unavoidable

15. Angular error for space angle
When requiring more than 2 lines also azimuth becomes well defined
Plot by J. Aguilars
5 lines detector

16. Angular error for space angle
10 line detector (plots by D. Dornic)
Contribution from reconstruction
Contribution from reconstruction + kinematics

17. Correction for detector inclination
Take sea current (here 9cm/sec) and direction
Apply rotation to correct for non-verticality of detector
Tiny effect (0.3º for 9cm/sec) but visible (0.05º)
0.64º
0.59º

18. Neutrino selection – Multiline events
98 
168 
Version 2
Version 3.2
Nline>1 ; Nhit>5
bchi2>tchi2
tchi2<4.3
Nline>1 ; Nhit>5
bchi2>1.7
tchi2<1.4

19. Neutrino selection – Single line events
54 
75 
Version 2
Version 3.2
Nline==1 ; Nhit>5
bchi2>tchi2
tchi2<2.7
tcosth>0.80
Nline==1 ; Nhit>5
bchi2>1.5
tchi2<0.95
tcosth>0.87

20. Effective neutrino areas
Effective area for n [m2]
Aart 12 lines
BBfit 5 lines
v3.2 v2

21. Effective neutrino areas – 10 lines detector
12 lignes – Aart
2 lines
3 lines
4 lines
5 lines
(plot by D. Dornic)

22. High amplitude events Single line fit Multi line fit
4 events with more than 200 pe seen
Brightest events with 238 and 275 pe
Badly described by MC

25. Technical changes (some only available in v3r2_1, next week)
Runstart GPS time used instead time from RUN table (warning message if not found) using DUAL function (from A.Albert)
Use nominal geometry from 12-line detector instead hardwired numbers
Use Offline Calibration with automatic selection of best calibration set (Corey)
Match between MC truth and PhysicsEvents Trees now based on TriggerCounter (Corey) instead of index

26. New executables BBdisplig : display events from ligier
BBdispfil : display events form file
BBbatch : batch processing and ntuple production
BBalert : process events from ligier and send GCN alert messages to different ligier
BBweblig : process events from ligier and produce image file without display