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

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

Version 2

Version 3.2

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

Effective amplitude Artificial saturation at 10 pe introduced Equalizes ARS responses

Effective distance Avoid pull towards d=0

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

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

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

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

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

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

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

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

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

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

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

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

Effective neutrino areas Effective area for n [m2] Aart 12 lines BBfit 5 lines v3.2 2 3 4 5 6 7 v2

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

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

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

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