CSd analysis Natalia for the European CS Scanning Team

Outline CSd tracking efficiency study  Benchmark track set  Scan Forth tracks Muon finding fraction 1

CSd tracking efficiency study

CSd tracking efficiency evaluation with benchmark track set 2 Measurement of the tracking efficiency on CS-doublets performed using Neutrino Events in order to evaluate the increase of the efficiency due to the use of the Compton procedure We selected a sample of 8 CSd for a total amount of 100 (already) validated tracks with a well defined topology. We performed a re-scanning of these doublets with the standard configuration in a (small) area including all these tracks. We evaluated the CSd scanning efficiency as the ratio between track measured in the re-scanning and total no. of tracks present in the CS doublet. We estimated both the double base-track efficiency and the increase of the efficiency due to the 3 out of 4 search after the Compton alignment. We repeated the 3 out of 4 search with 2 different link configuration: i) “standard” + QualityCut = S < 0.25 * N (on – line cut is S < 0.25 * N - 3.0) ii) “standard” without quality cut

CSd tracking efficiency evaluation with benchmark track set 3 Brick Double base- tracks 3 out of 4 “standard” link config. 3 out of 4 “no Quality Cut” link config Tot  db ~74±6%   sb ~ 86±3%  3/4 Standard ~ 82±5%  3/4 noCut ~ 89±3% Estimation of the manual check weight: 3 out of 4 “standard” link config.: 4.2 tr/cm 2 3 out of 4 “noCut” link config.: 6.6 tr/cm 2

CSd tracking efficiency evaluation with Scan Forth tracks Sample of tracks attached to the primary neutrino vertex of several 2008 events published onto the DB Selection of tracks reaching the end of the brick (at least plate 56) and intercepting the scanned area (124 tracks) Matching between these tracks and the validated track sample of the correspondent CS-doublet Ranking of the combinatorics with the following   variable and selection of the signal with a cut on the   BrickCSd Tracking efficiency:  =89/124 ~ 72 ± 6%  sb ~ 85 ± 3% 4

Brick – CS connection with Scan Forth tracks  ~64  m  ~69  m  ~10 mrad  ~12 mrad 5

Muon Finding

Muon 417 developed bricks 6 73 NC 344 CC 91 without muon candidate 253 with muon candidate Muon finding fraction:  4/4 =237/344 ~ 69 ± 4%  3/4 =253/344 ~ 73 ± 3% 237 found as double base-track16 found as 3 out of found with the standard cut (within 60 mrad from the prediction) 29 temporary flagged as muon (waiting for the brick scanning) 15 standard1 flagged

Some details about found muons… 7  ~ 45 Mean ~ -9 mrad Mean ~ 66 mrad

8  ~7  m  ~9  m  ~3 mrad Some details about found muons…

Residuals wrt Kalman prediction 9  ~9 mm  ~21 mrad  ~22 mrad

Residuals wrt Linear prediction 10  ~12 mm  ~10 mm  ~22 mrad  ~25 mrad

Conclusions 11  Evaluation of the tracking efficiency using two methods: Benchmark track set  db  ~ 74±6% Scan Forth tracks  db ~72±6%  Muon finding fraction:  4/4 ~ 69 ± 4%