Non-oscillation physics

Report of the WG

M. Sioli, OPERA Collaboration Meeting, Ankara, 1-3 Apr 2009

OPERA-LVD coincidence study

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 OPERAT600 ~90m OPERALVD ~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

People involved in this preliminary analysis:MS, Dario A. and Marco Selvi (LVD)People interested to join?

Locations of the detectors in the Labs

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170 m

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R~D~1/(pT+p0)

R = muon-core distanceD = di-muon relative distance

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LVD detector• 3 identical towers in the detector

• 35 active modules in a tower

• 8 counters in one module

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The detector: basic elementsThe 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 @ =420 nm

Flash point at: ~39oC

PMT: FEU-49B Photocathode diameter: d=15 cmQuantum efficiency: 10-15%

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Statistics for OPERA and LVD

OPERA statistics (2008 run, 19th Jun 3rd Nov, extractions 682952): 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.rootfiles without any selection!

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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

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Fake-rate estimation

Given the two poissonian single-rates:

LVD = 0.1 Hz

OPERA = 0.06 Hz

the fake rate into a = 1s time window isfake = LVD OPERA~ 10-8 Hz

In a run period T=5 months the background is therefore

Nbg = fakeT = 0.1 events

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Time corrections for OPERA and LVD

OPERA: tevent = tclock + tfiber + telec

tfiber + telec= 45238.6 ns

LVD: tevent = tclock + tfiber (i) - telec

tfiber (1) = 42116.5 ns (Tower 1)

tfiber (2) = 42063.8 ns (Tower 2)

tfiber (3) = 42040.6 ns (Tower 3)

telec = 350 ns

N.B. tclock is in common (it’s the time stamp freezed before the transmission)

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 s (both in OPERA and in LVD) N.B. In the *_filter.root files, this

is not true: BEAM = spill start ±1 ms

Coincidence study: results

t<1ms

t<15 s

Beam events (intra-spill coincidences)

Triangular function between ±10.5 s well centered around zero: nice independent check of timing inter-calibration!

Beam events (intra-spill coincidences)

3 events with t<100 ns (within timing resolution): events generated by the SAME neutrino?(e.g. large angle di-muonevents)

Under investigation the possibility to study someexperimental handles(e.g. slopes on the XZ plane in both detectors to look for vertexing)

Cosmic events in coincidence

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)

LVD OPERA

Zenith-Azimuth mapTeramo ValleyBeam events

One of these 38 events: LVD view

One of these 38 events: OPERA view

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)

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

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

Starting situation

(From the work of Christoph, Irisha and Dima)

Results after 3 iterations

New shifts on x and z

X correction (cm)

Z correction (cm)

Plane2_SM1 0.031 0.441

Plane4_SM1 0.008 0.491

Plane6_SM1 0.047 0.447

Plane2_SM2 0.018 0.446

Plane4_SM2 0.121 0.310

Plane6_SM2 0.047 0.225

Corrections (in cm) we applied to the x and z shifts in the Alignment files in OpUtils/v*/data/DriftTube/Alignment

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

Study of the rotations between stations (magnet off)

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

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

Study of bending intra-station

DF within 1 mrad, mostly fluctuating randomlyDifficult to correct: insert in the systematic evaluationSome exceptions:

Results of the alignment

MAGNET OFFlivetime REAL = 13.635417 days

rate REAL spectro = 359.138275 events/day

doppietto 0cr real = 0.938534 +/- 0.046374 doppietto 1cr real = 1.045012 +/- 0.050989 doppietto 2cr real = 1.085923 +/- 0.064351 doppietto 3cr real = 1.013624 +/- 0.052733

entries 1 : 120.275; entries 2 : 123.282; entries 3 : 83.6791; entries 4 : 108.394

MAGNET ONlivetime REAL = 113.423752 days

rate REAL = 2326.117733 events/day

rate REAL spectro = 360.444787 events/day

doppietto 0cr real = 1.294306 +/- 0.021576 doppietto 1cr real = 1.356918 +/- 0.022803 doppietto 2cr 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

CR stability as a function of data taking

Event number

Beam muons: cross check of the analysis

Charge mis-Id: 4/215 eventsCharge mis-Id: 4/215 events

Charge/momentum unfolding

Standard method: matrix inversion

Log(1/p)

rate MC spectro = 783.833374 events/dayrate REAL spectro = 462.980630 events/day ratio REAL/MC spectro = 0.590662Misidentification probabilities:epp = 0.943793epm = 0.056207emp = 0.059502emm = 0.940498err epp = 0.013053err epm = 0.013053err emp = 0.015705err emm = 0.015705Average Misidentification probabilityeta media = 0.057596err eta media = 0.001833cr mc truth = 1.372291 +/- 0.021870cr mc = 1.331156 +/- 0.021166cr mc unf = 1.372249 +/- 0.021166cr real = 1.343745 +/- 0.014359cr real unf = 1.397389 +/- 0.017094

= 1.397 ± 0.017

)1(RR1

Rmeasured

measuredunfolded

Charge/momentum unfolding

More refined methods: Bayes and SVD + regularizations

Check on MC simulation (Bayes method on q/p)

Charge/momentum unfolding

More refined methods: Bayes and SVD + regularizations

q/p Bayes

q/p SVD

Charge/momentum unfolding

More refined methods: Bayes and SVD + regularizations

Cos Bayes

Rock Bayes