Update on the PS analysis

1. Update on the PS analysis • Outline • Transition to SeaTray • Nhits – PSF correlations • Fixed search, Full sky search Claudio Bogazzi AWG videoconference 15/07/2011

2. Documentation available • First talk at the collaboration meeting in Amsterdam (Nov. 2010) • Since then, updates @CERN and @MOSCOW + AWG videoconferences. • NEW: http://www.nikhef.nl/~claudiob/pnt2/index.shtml (all the documentation will end up here) • Internal note available: ANTARES-PHYS-2011-005 • Version 1 submitted on the CDS system on Wednesday (night), 13th. • Most of the work is included, however still a couple of things are missing: 1) Full sky search analysis (see later) 2) Systematic uncertainty on Nhits (see also later) • All the plots / results in the note are made with our aafit production.

3. Transition to SeaTray • Adopted our tools to read the mudst files of the SeaTray production. Top left: run number distribution for selected events after a cut Λ > -5.8 and β < 1° Bottom left: same as before, but with a smaller range. 243 runs (QB >= 1) not reconstructed with the SeaTray production (18 days of livetime in total). Already informed Thomas, waiting the recovery.

4. Transition to SeaTray • All the SeaTray production files already converted to a format “more familiar” to us. Top right: cumulative lambda distribution for selected events with Λ > -5.8 and β < 1° Bottom right: same as before, but with Λ > -5.2 In both plots we consider the same range of runs With a more stricter cut the aafit production has more events (2864 vs 2804). Remember: selection of basic runs different for the 2 productions. Livetime: 798 days vs 771

5. Transition to SeaTray • Some numbers for the SeaTray production (mudst file): • Basic runs, NO SCAN: 6903 runs, 771.9 days • Basic runs, NO SCAN, missing: 243 runs, 18.9 days (!) • Basic runs, NO SCAN, no alignment but in SeaTray prod: 46 runs, 5.4 days • These last 46 runs are not available in our aafit production. The reason is that there is no alignment during the run interval What happens is the algorithm looks always for the closest alignment (for some events will be the one before the start of the run, for others the one after the end of the run) No reasons to keep these runs -> cut to reject them Run duration Alignment time Alignment time

6. SeaTray - Rbr MC (zenith) Λ > -5.0 Λ > -5.2 149 basic runs (13.8 days of livetime) missing in the rbr MC production (these and the next plots not scaled yet)

7. SeaTray - Rbr MC (lambda) Fig. 25 in the note SeaTray prod. for data Rbr MC (up nu/anu, down nu/anu, MUPAGE) Aafit standalone prod. for data Old MC (up nu/anu, CORSIKA)

8. SeaTray - Rbr MC (lambda) Fig. 25 in the note Muons (previous slide): mupage overestimates a bit the data in the high lambda region (not a surprise). Better modeling (ratio < 1.5) . Neutrinos (this slide): good agreement as before.

9. SeaTray - Rbr MC (lambda)

10. Nhits s • In order to take into account correlations between the number of hits and PSF we decide to change a bit the algorithm at the PE generation level. • Reminder: so far for the PE generation we used two distributions of the number of hits. One for the background ( data ) and one for the signal (E-2 neutrinos MC) Black dots - > PE background . Blue line -> likelihood (background) Red line -> PE (signal) and likelihood (signal) Using the data distribution for the PE bkg generation is a conservative approach. All the results in the note are made with this procedure

11. Nhits studies • Reminder: in the PE generation, a declination dependent distribution of log(β) is used. • In the search method instead we require a smooth parameterization of the PSF (help the fit to work well)

12. Nhits studies • Now, for the PE generation, the PSF as well as the number of hits are extracted from a 3D histogram log(β) vs sin(δ) vs Nhits Projection of the z-x axis From the 2D histo we select two random numbers, one for Nhits the other for the PSF

13. Nhits study • Small change also at the likelihood computation level (for the background) Λ > -5.2 Included now muon contribution on the Nhits distribution (14%) -- data -- nu MC -- mu MC -- total MC Let’s have a look at the first sensitivity plots with these improvements

14. Fixed search • Btw, found a bug on the way we scaled the MCs with the livetime: 13% more events NOW • In the note all the MC vs data plots are not affected by this bug (was already fixed), but the ACCEPTANCE and of course the SENSITIVITY are. Λ > -5.2 Value for 2 declinations (30° and 40°) not yet included

15. Fixed search Λ > -5.4 not yet ready (not a big deal since this cut is not our first choice) To be compared with figure 39 in the note.

16. Full sky search Λ > -5.2 and δ = -70° Distribution of the test statistic. Q3σ = 15.90 Q5σ = 25.59 Probability of 3σ (5σ) discovery as function of the mean number of signal events.

17. Conclusions & next steps • SeaTray transition already started. As soon as all the data are reconstructed we can definitely use it. • Rbr MC: first data / MC plots available. Promising results. Need to make a decision: do we use it or we continue with the old MC? • Search algorithm adapted to take into account Nhits – PSF correlations. • Fixed a bug related on the livetime scaling for the MC->13% more evts • New results for the fixed and the full sky search available (still a couple of declinations are missing as well as the > -5.4 cut) • Update the note with all these new results and inform the collaboration. • Already received comments from Juergen and Juande (already answered to some questions).