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Non-oscillation physics

Non-oscillation physics. Report of the WG. M. Sioli, OPERA Collaboration Meeting, Ankara, 1-3 Apr 2009. OPERA-LVD coincidence study. People involved in this preliminary analysis: MS, Dario A. and Marco Selvi (LVD) People interested to join?.

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Non-oscillation physics

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  1. Non-oscillation physics Report of the WG M. Sioli, OPERA Collaboration Meeting, Ankara, 1-3 Apr 2009

  2. OPERA-LVD coincidence study People involved in this preliminary analysis:MS, Dario A. and Marco Selvi (LVD) People interested to join? • The main physical motivation is the study high pT phenomena • Large muon separation is the convolution of muon production height and meson transverse momentum: • Roughly double the MACRO linear extension: • MACRO ~70m • OPERAT600 ~90m • OPERALVD ~170m • At this distances/pT (> 2 GeV/c) we get inside pQCD  predictions not strictly related to forward modeling • As a byproduct, also study beam events: large angle di-muon events? • Video-meeting organized in Feb to define the initial steps

  3. Locations of the detectors in the Labs 170 m

  4. R~D~1/(pT+p0)a R = muon-core distance D = di-muon relative distance

  5. 3 identical towers in the detector • 35 active modules in a tower • 8 counters in one module LVD detector

  6. The detector: basic elements The scintillation counter: External dimensions: 1.5 x 1 x 1 m3 Scint. composition: CnH2n+2 <n>=9.6 +1 g/l PPO+ 0.03 g/l POPOP Scint. density: ~ 0.8 g/cm3 Attenuation lenght: > 15m @ l=420 nm Flash point at: ~39oC PMT: FEU-49B Photocathode diameter: d=15 cm Quantum efficiency: 10-15%

  7. Statistics for OPERA and LVD • OPERA statistics (2008 run, 19th Jun  3rd Nov, extractions 682952): • 644138 events (634390 cosmics + 9748 beam) • 3151 hours of livetime (3287.7 elapsed) • 95.8% dutycycle • cosmic’s rate: 0.056 Hz • (average) beam’s rate: 0.00086 Hz Taken from *_filter.root files without any selection!

  8. Statistics for OPERA and LVD • LVD statistics (same period): • 1152888 events (1139547 cosmics + 13341 beam) • 3284.5 hours of livetime (3287.7 elapsed) • 99.9% dutycycle • cosmic’s rate: 0.097 Hz • (average) beam’s rate: 0.0011 Hz • At least 2 different counters in coincidence inside 250 ns • Not tagged as HIGH RATE • Energy release > 10 MeV

  9. Fake-rate estimation Given the two poissonian single-rates: mLVD = 0.1 Hz mOPERA = 0.06 Hz the fake rate into a Dt = 1ms time window is mfake = mLVD mOPERADt ~ 10-8 Hz In a run period T=5 months the background is therefore Nbg = mfakeT = 0.1 events

  10. Time corrections for OPERA and LVD • OPERA: tevent = tclock + Dtfiber + Dtelec • Dtfiber + Dtelec= 45238.6 ns • LVD: tevent = tclock + Dtfiber (i) - Dtelec • Dtfiber (1) = 42116.5 ns (Tower 1) • Dtfiber (2) = 42063.8 ns (Tower 2) • Dtfiber (3) = 42040.6 ns (Tower 3) • Dtelec = 350 ns N.B. tclock is in common (it’s the time stamp freezed before the transmission)

  11. Procedure to find tclock • In OPERA, loop on the timeStamps of the digit’s events and find the minimum value • 10 ns granularity • different from the event timeStamp in *_filter.root files, freezed at the beginning of the corresponding DAQ cicle • In LVD, timeStamp of the first fired tank • Each event is tagged beam event if its timeStamp is within the spill start ±20 ms (both in OPERA and in LVD) • N.B. In the *_filter.root files, this is not true: BEAM = spill start ±1 ms

  12. Coincidencestudy: results Dt<1ms Dt<15 ms

  13. Beam events (intra-spill coincidences) Triangular function between ±10.5 ms well centered around zero: nice independent check of timing inter-calibration!

  14. Beam events (intra-spill coincidences) 3 events with Dt<100 ns (within timing resolution): events generated by the SAME neutrino? (e.g. large angle di-muon events) Under investigation the possibility to study some experimental handles (e.g. slopes on the XZ plane in both detectors to look for vertexing)

  15. Cosmic events in coincidence LVD m OPERA 38 events peaked at ~ -573 ns! Explanation (confirmed by visual inspection): all events coming from the “Teramo valley” sticking OPERA first and LVD after. Distance measured by ToF: 573ns*0.3m/ns=172m (Expectations: dmin:dmax=170m:176m  dtmin:dtmax= -587ns:-567ns)

  16. Zenith-Azimuth map Beam events Teramo Valley

  17. One of these 38 events: LVD view

  18. One of these 38 events: OPERA view

  19. Conclusions and plans • A first analysis has been carried out on 2008 data • Found 145 beam events in coincidence (intra-spill) • Useful to cross check data and timing intercalibration • Extend the analysis to look for (or exclude) events generated by the same neutrino interaction • 38 cosmic events in coincidence • All coming from the Teramo valley • Still to recognise their multiplicity: same muon or double muon?  Track reconstruction in YX view! • Extend the analysis to include older data (outside run period) • Monte Carlo prediction using a QCD-inspired code (e.g. DPMJET): production ready to start with FLUKA (parameterized generators in this case are useless)

  20. Atmospheric muon spectrum and charge ratio(N. Mauri and M. S.) • News with respect to the last meeting: • Main bottleneck (HPT alignment) definitively solved, at least for the purpose of this analysis (see later) • Unfolding procedure • Systematic error evaluation • Paper on cosmic rays restarted: • Within April, a first draft version will be circulated and discussed within the WG

  21. Relative alignment between HPT stations • Start correcting in DX and DZ intra-doublet (magnet on) • Iterate the procedure until it converges • Correct for rotations intra-doublet • Check for bumping • Correct for rotations between doublets (magnet off) • Final check plotting R vs F

  22. Starting situation (From the work of Christoph, Irisha and Dima)

  23. Results after 3 iterations

  24. New shifts on Dx and Dz Corrections (in cm) we applied to the Dx and Dz shifts in the Alignment files in OpUtils/v*/data/DriftTube/Alignment

  25. Study of the rotations intra-station (magnet on) VALUE ERROR HPT 1-2 SM1 1 a_zy -1.47625e-04 3.59046e-03 2 a_xz 3.36670e-05 2.80332e-03 3 a_xy 7.42502e-06 5.31426e-03 HPT 3-4 SM1 1 a_zy 7.00820e-05 3.24239e-03 2 a_xz 1.19035e-04 2.53571e-03 3 a_xy 7.93161e-05 4.96220e-03 HPT 5-6 SM1 1 a_zy 5.90508e-05 3.86746e-03 2 a_xz -2.85497e-05 2.91879e-03 3 a_xy -6.74481e-05 5.53176e-03 HPT 1-2 SM2 1 a_zy -1.83383e-04 3.26790e-03 2 a_xz 1.27684e-06 2.54575e-03 3 a_xy 2.87309e-04 5.05467e-03 HPT 3-4 SM2 1 a_zy -5.89939e-06 3.52798e-03 2 a_xz -2.07120e-04 2.77148e-03 3 a_xy -9.40481e-05 5.64860e-03 HPT 5-6 SM2 1 a_zy 3.93602e-04 6.07937e-03 2 a_xz 1.37789e-04 4.30017e-03 3 a_xy 8.21664e-06 9.34348e-03

  26. Study of the rotations between stations (magnet off) VALUE ERROR 1 arm SM2 1 a_zy -3.69397e-04 1.93282e-02 2 a_xz -1.82379e-04 1.53938e-02 3 a_xy 1.58743e-04 2.34608e-02 2 arm SM2 1 a_zy 1.57396e-04 1.82462e-02 2 a_xz 3.34168e-04 1.36295e-02 3 a_xy -3.78349e-05 2.20552e-02 VALUE ERROR 1 arm SM1 1 a_zy -3.89791e-04 1.79461e-02 2 a_xz 8.46438e-06 1.41929e-02 3 a_xy 1.19200e-04 2.01941e-02 2 arm SM1 1 a_zy -8.77744e-05 1.45676e-02 2 a_xz 1.19218e-04 1.10185e-02 3 a_xy 3.94737e-04 1.88165e-02

  27. Study of bending intra-station DF within 1 mrad, mostly fluctuating randomly Difficult to correct: insert in the systematic evaluation Some exceptions:

  28. Results of the alignment MAGNET ON livetime REAL = 113.423752 days rate REAL = 2326.117733 events/day rate REAL spectro = 360.444787 events/day doppietto 0 cr real = 1.294306 +/- 0.021576 doppietto 1 cr real = 1.356918 +/- 0.022803 doppietto 2 cr real = 1.253912 +/- 0.025922 doppietto 3 cr real = 1.340062 +/- 0.025571 entries 1 : 129.03; entries 2 : 127.814; entries 3 : 83.5811; entries 4 : 98.9485 MAGNET OFF livetime REAL = 13.635417 days rate REAL spectro = 359.138275 events/day doppietto 0 cr real = 0.938534 +/- 0.046374 doppietto 1 cr real = 1.045012 +/- 0.050989 doppietto 2 cr real = 1.085923 +/- 0.064351 doppietto 3 cr real = 1.013624 +/- 0.052733 entries 1 : 120.275; entries 2 : 123.282; entries 3 : 83.6791; entries 4 : 108.394

  29. CR stability as a function of data taking Event number

  30. Beam muons: cross check of the analysis Charge mis-Id: 4/215 events

  31. = 1.397 ± 0.017 Charge/momentum unfolding rate MC spectro = 783.833374 events/day rate REAL spectro = 462.980630 events/day ratio REAL/MC spectro = 0.590662 Misidentification probabilities: epp = 0.943793 epm = 0.056207 emp = 0.059502 emm = 0.940498 err epp = 0.013053 err epm = 0.013053 err emp = 0.015705 err emm = 0.015705 Average Misidentification probability eta media = 0.057596 err eta media = 0.001833 cr mc truth = 1.372291 +/- 0.021870 cr mc = 1.331156 +/- 0.021166 cr mc unf = 1.372249 +/- 0.021166 cr real = 1.343745 +/- 0.014359 cr real unf = 1.397389 +/- 0.017094 Log(1/p) Standard method: matrix inversion

  32. Charge/momentum unfolding More refined methods: Bayes and SVD + regularizations Check on MC simulation (Bayes method on q/p)

  33. Charge/momentum unfolding q/p Bayes q/p SVD More refined methods: Bayes and SVD + regularizations

  34. Charge/momentum unfolding Cos q Bayes Rock Bayes More refined methods: Bayes and SVD + regularizations

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