Physics coordination meeting summary report Emulsion simulation: GenIma Update of brick finding analysis /e separation: test beam analysis HE cosmic

Physics coordination meetingsummary report

• Emulsion simulation: GenIma

• Update of brick finding analysis

/e separation: test beam analysis

• HE cosmic ray muons, e/ identification and νμ → νe oscillations

• Multi-prong tau decay analysis

• Test at Fermilab in 2005

D.DuchesneauOPERA collaboration meeting

Hamburg, June 6th 2004

(on behalf of Pasquale)

Original talks are accessible on OPERA file server.

Update of brick-finding analysis

The optimization of the neural network for the subclasses for CC and NC events is done.

The analysis for CC events was presented during the last meeting at Cern (December). A little improvement compared to the last results shown comes from an optimization for QE like events. The analysis for NC events is completed as well. Two subclasses are defined: Long events and Short events (optimization for the taue QE).

The results are given in this presentation: the details will be given at the next collaboration meeting.

Cern, 23/04/2004C. Heritier

NN:wall probabilities

Tracking:Fitted vertex error distribution(3D gaussian)

Bricks 3D probabilitymap

+Convolution of the two probability distributions and integration on the volumes of the bricks

Interaction brick found by selecting the one with thehighest probability (more sophisticated strategies possible)

Building the 3D bricks probability map:

12 3

(C.Heritier, Nov. 2003)

Update of brick-finding analysis

Application of the 3D map: 3 extraction strategies are tested

• Extraction of the highest probability brick (only 1 brick)

• Extraction of the second most probable brick if the vertex is not found under the condition P1-P2 < threshold (2 bricks)

• Extraction of all bricks with significative probabilities (cutoff at 1%) until the vertex is found.

Cern, 23/04/2004C. Heritier

Extraction strategy: brick Scanning overload (numuCC):

Highest prob. Brick (HPB) 73.5% proposal:73.0%

-

HPB + second most prob.Brick (SMPB), if P1-P2<0.1

74.4% (+0.7%) 1.9%

HPB + SMBP, if P1-P2<0.2 75.3% (+1.6%) 3.4%

HPB + SMPB, if P1-P2<0.3 76.0% (+2.3%) 4.4%

HPB + SMPB, if P1-P2<0.4 76.6% (+2.9%) 5.5%

HPB + SMPB, if P1-P2<0.5 77.4% (+3.7%) 6.4%

HPB + SMPB, cutoff at 1% 81.3% (+7.6%) 13.0%

All bricks, cutoff at 1% 82.5% (+8.8%) 16.9%

Cern, 23/04/2004

Application of the 3D map for the oscillated events. The results are for the mix of QE and DIS. The gain in efficiency is put in brackets.

Extraction strategy:

brick

e

brick

h

Scanning overload (numu NC):

Highest prob. Brick (HPB)

75.3%Proposal:80.1%

63.5% Proposal:69.8%

0%

HPB + SMPB, if P1-P2<0.1

78.4% (+3.1%) 67.6% (+4.1%) 8.9%


80.0% (+4.7%) 69.4% (+5.9%) 13.0%


80.8% (+5.5%) 70.3% (+6.8%) 16.1%


81.3% (+6.0%) 71.0% (+7.5%) 18.5%


81.9% (+6.6%) 71.5% (+8.0%) 20.6%

HPB + SMPB, cutoff at 1%

83.6% (+8.3%) 72.8% (+9.3%) 30.8%

All bricks, cutoff at 1%

84.8% (+9.5%) 74.6% (+11.1%) 53.6%

Cern, 23/04/2004

Application of the 3D map for the e and h oscillated events.

Extraction strategy:

brick

brick

e

brick

h

Total scanning overload (NC+CC)

Additional mass reduction

Proposal 73.0% 80.1% 69.8% - -

1 brick 73.5% 75.3% 63.5% - -

2 bricks (gain/proposal)

81.3% +8.3%

83.6% 3.5%

72.8% +3.0%

18.4% 1.2%

All bricks (gain/proposal)

82.5% +9.5%

84.8% +4.7%

74.6% +4.8

28.0% 1.9%

Cern, 23/04/2004

The total scanning overload is performed taking into account the rate NC/CC. The additional mass reduction of the target is estimated taking into account the mass reduction expected with the nominal beam.

• If only one brick is extracted, the efficiency for the channel is a little greater than the proposal, for other channels, they are lower. • But, if we decide to extract the second most probable brick, therefore the efficiencies are better than those of the proposal for all channels.For instance, if all bricks are extracted, for the channel, the gain in efficiency is 9.5% - 1.9% = 7.6% better than the proposal.

/e separation: pure pion test beam analysis

Francesco Di CapuaUniversity of Naples

• Physics motivations• Scanning of data from a pure pion test

beam• Data analysis (preliminary results) • Outlook

Physics motivation

• Measure P( e)

• Try to improve the technique in order to reduce the misidentification probability

e

he

Charm

e

event wrong interpretation

Low electron contamination pion beam needed

N X eN eCX

Current algorithm (1)

• Basic principle: rate of energy loss is different for electrons and hadrons:

mmEzE

mmXeEzE Xz

170)(

6.5)(

int0

000

First part: 2 analysis

: separator

1mm ~ 2mrad

Current algorithm (2)

Second part: shower analysis

• Open a cone around the leading track

• Count segments inside the cone energy measurement

• Check the compatibility between the momentum of the leading track, the energy of the shower and the particle hypothesis

Other techniques

• Neural network

Pure test beam• 3 bricks exposed at different momenta (2, 4, 6 GeV)

• Lead plate before focusing magnet with about 5 X0

• Lead glass calorimeter to monitor the electron contamination (10-3 level)

• Muon contamination : 30%

• TB period (July 2003)• TB design (G. De Lellis)• Monte Carlo studies (G. De Rosa and A. Marotta) • Electronic detector (I. Kreslo)• Beam parameter tuning (G. De Lellis and I. Kreslo)• Refreshing and Development (G. Rosa, C. Sirignano)• Brick assembling (BAM)• Brick exposure (M. Cozzi, G. De Lellis, G. De Rosa, I. Kreslo, L. Scotto, V. Tioukov,)

People involved:

Scanning of data• so far 2 bricks analyzed with the ESS• 30 plates scanned for each brick (scanning surface: 2x2 cm2)• Hardware configuration(old prototype)

Off-line analysis:

FEDRA software

Data are available on www.ntslab01.na.infn.it/public/tb_july2003

2 GeV Pions

Momentum measurement by MCS

average beam momentum measurement

Brick 1 (4 GeV) Brick 2 (2 GeV)

<Pbeam>=4.010.02 <Pbeam>=1.960.01

ncell ncell

Momentum measurement by MCS track by track

Brick 1 (4 GeV)

Tracks sample (nseg>=5)

1/P

1/P

P

P

Brick 2 (2 GeV)

2 analysis – preliminary results

2e

2

= (95.80.5)% at 4 GeV

= (97.20.5)% at 2 GeV

= 0.7 + 0.3 =(94.0 0.5)% at 2 GeV

= (96.0 0.5)% at 4 GeV

Taking into account for muon contamination ( =100%)

4 GeV

First MC studies (very preliminary)

2 MC / data comparison

(4 GeV pions)

2 analysis result on MC events:

4 GeV (%)

94.7

2 GeV 95.4

4 GeV e 76.8

2

Outlook• Tune MC with data (instrumental backg. missing)

• Evaluate with MC the effect of cut on segments (nseg>4)

• Shower analysis

• Measurement of P( e) for 2,4,6 GeV pions

• Other studies : detection of pion interactions (measurement of the background for decay)

HE cosmic ray muons,e/ identification and μ → e oscillations

Max Sioli, Physics Coordination Meeting, CERN 23 Apr 04

(Laurea Thesis of Antonio Petrella)

Outline of this study:

• Simulate HE cosmic ray muons inside OPERA (integrated in one year) and secondary particles generated by them;

• Compute the effect of these background tracks on the e/ Id;

• Example of application of this study:μ → e oscillation channel.

e

Example of a e

CC event overlapping an e.m. shower

Due to the huge number of secondary particles (Ekin_cut = 1 MeV), simulation has been restricted to 9 walls (3328 brick/wall):8 insensitive volumes and 1 sensitive volume (in the center)

• cone aperture = 50 mrad (A50)

• cone aperture = 250 mrad (A250)

• relative deviation wrt event axis =200 mrad (D200)

• releative deviation wrt event axis = 400 mrad (D400)

For each emulsion:

e/ Id: use of a NN

is passed to the NN (using the prescriptions in the Laurea Thesis of L.S. Esposito)

Efficiency parametrized with:

e/ Id: results

Energy reconstruction w/wo bg

Number of tracks inside the

cone is proportional to the

shower energy

Energy resolution computed from:

and parametrized with:

Impact of e.m. showers on CS

This bg is not uniform as comptonelectron from lead.

Here we considered 1 MONTH offading time

Similar results obtained using the strong fading model

•Strong fading model approximation:g(t) = g0exp(-t/)n

μ → e oscillation channel• This computation has been performed

according to hep-ph/0210043 (therefore NOT a full simulation)

• The only differences are:– Signal efficiencies taken from Status Rep

and CS note;– Signal efficiency computed with eId

parametrizatrization;– Energy resolution smeared out according

to parametrization;

In each ( sin2(2m232 ), we computed the curve 222

min = 4.61, corresponding to 90% C.L.

•Main contribution to the sensitivity arises from the poissonian

fluctuations of bg event numbers.

•Nominal beam intensity

(1.65 kt effective mass)

Multiprong tau decay channel analysis

Charm background (+ double charm)

kinematical analysis with likelihood variable taking into account correlations

Differences with respect to the last presentation in Napoli

- add short decays

- use of more sophisticated likelihood analysis to take into account variables correlations

- oscillated CNGS beam spectrum at m2=2.4.10-3eV2

Muriele LAVY

CC

CC charm

C charm

Only one secondary vertex detected : 2.3% of these events

a vertex is detected when the distance from this vertex to the others is higher than 15 microns |dvertex|>15 m

Double charm production in neutrino interactions

N

1ii

totkink tkink θ CC

CC charm

C charm

SHORT DECAY

/charm

With pre-selection cutsrad radLONG DECAY

Multiprong tau decay channel analysis

- CC events with 3 hadrons

m2 = 2.410-3 eV2 , 6.71019 pot.year-1 5 events

- CC events with 1 charmed particles

264 events 7 events

- CC events with 2 charmed particles

10 events 0.012 events

- NC events with 2 charmed particles

3 events 0.045 events

Number of events expected in OPERA detector per year

not detected + 1 secondary vertex with nprong=3

not detected + 1 secondary vertex with nprong=3 + 1 charm not detected

1 secondary vertex with nprong=3 + 1 charm not detected

neglected

Multiprong tau decay channel

Karlen method 1

1 Dean Karlen «Using projections and correlations to approximate probability distributions » arXiv:physics/9805018 v1 1998

Principle : probability distribution in multidimensional space built taking into account the correlations between variables

improve discrimination power


Karlen method long decay

27 25 20 10 5

44 52 60 75 85

6 variables used : - total transverse momentum - total energy - total angle - mass variable - jet energy - kink angle

purity

efficiency


Karlen method short decays

40 30 20 10 5

62 67 73 85 88

4 variables used : - total transverse momentum - total energy - mass variable - jet energy

purity

Efficiency


Karlen method

Short + Long decays

shortlong

short/long


= trig brick geom vertex id short kine

0.76 0.94 0.947 0.90 0.70 0.143

= trig brick geom vertex

2 id long kine

0.76 0.94 0.897 0.90 0.30 0.133

SHORT DECAY

LONG DECAY

m2 = 2.4.10-3 eV2 N = 182 m2 = 2.0.10-3 eV2 N = 127

BR(3h) = 15%NhNh1.58

5 years

.BR=1.25%

After analysis

Ncharmcc


Hypothesis used : kinematical obtained from the kinematical analysis with m2eVis the same for the othersm2 in the table

5 years in the OPERA detector

3h

m2 (eV2) 1.3.10-3 2.0.10-3 2 .4.10-3 3.0.10-3 back.

Nh 0.67 1.58 2.22 3.52 0.44

Feldman Cousins approach

-h-h+h-


Channel Signal (m2 (eV2) ) BR BR Background

1.3 10-3 2.0 10-3 3.0 10-3

e 1.8 4.1 9.2 19.4% 0.175 3.4% 0.31

1.4 3.4 7.6 16% 0.175 2.8% 0.33

h 1.5 3.5 7.8 5.8% 0.50 2.9% 0.42

3h 0.7 1.6 3.5 8.3% 0.15 1.25% 0.44

Total 5.4 12.6 28.1 49.5% 1 10.9% 1.5

Hypothesis used : R =1.25 % for the cinematic analysis with

m2eVis the same for the othersm2 in the table

5 years in OPERA detector

The OPERA test in 2005 on the NUMI beam

D.Autiero, M. KomatsuCERN, 23/4/2004

Near detector

The beam is adjustable: by moving the horns and target, different energy spectra are available.

4x1020 protons on target/year

Near detector location:

LE beam: 1 CC / Kg /day

ME 2 CC / Kg /day

HE 3.2 CC / Kg /day

1 brick = 8.3 Kg >1 CC / brick/hour

In 2005 it is foreseen a period at HE for about 10% of the time

•Start of commissioning (5x1012

protons/pulse)

20 November 2004 (1 month)

Beam line components not cheched initially with the same accuracy as CNGS, will be debugged during commissioning

Start of physics:

January 2005 ?

OPERA test-beam:

Two independent setups:

ECC array with old DONUT SFT detector (mini-OPERA)To collect the largest possible number of neutrino interactions in the bricks:

Scanning technique practice (opera rehearsal),vertex studies, 0 reconstruction, multiple scattering, p& K IDuse different passive materials (lead, iron), run for a long time also with LE beam, collaboration with the DONUT people SFT + MINOS for muon ID

Hybrid detector: get a few hundreds of well measured events in with:

ECC+ Si trackers + ECAL + neutron detector + MINOS

Mini-OPERA

Mini-OPERA

Mini-OPERA

Hybrid sophisticated detector:

The high intensity of the NUMI beam at the near detector location allows to work with a small target mass and compact and sophisticated detectors (not possible with CNGS), made with all recycled componentsIt is possible to build a precise detector around a single brick

It is a good occasion to perform a precise measurement of all what is produced in the neutrino interaction in the brick and to check also the production of backward particles which is relevant in OPERA for the BF analysis. We are interested in particular in the HE run

These results are also useful for the neutrino community for the investigation of nuclear effects, bricks can be made in Pb, Fe

This is not a new experiment (in competition with MINERVA) but just a test-beam performed with a small setup with the goal of collecting a few hundreds CC well measured.

• Precise tracking in the forward and backward direction• Forward calorimetry• Detector for backward neutrons

ECC ECAL

Minos nearDetector

(HCALMuon ID)

Detector forBackward Neutrals

(scintillator bars)

Silicon tracker planes

Veto

1.5 m Max

The detector is made with existing/recycled componentsWe can afford a sophisticated detector for one brick, given its small size. This is possible due to the high neutrino flux.

The detector can fit in a space of 1.5 m longitudinal, < 1 m transverse which, can be available in between Minerva and Minos due to the MINOS ND coils (The magnetic field map should be checked). The idea is to change the brick exposed a few times per day (depending on the max number of interactions we want to accept per brick (HE run: 27 interactions per day).

The neutron detector will be made of scintillator strips ‘we can recycle some of the TT building waste) with WLS fibers readout and M64 photomultipliers + standard opera TT electronics. The layers of strips will be crossed in X and Y.

For the neutron detector one possibility is to have just in the side close to the brick a thin foil of lead to be used as preshower in order to distinguish photons from neutrons. This could be put just at the beginning or after a few layers (2 layers) of scintillator in order to allow to detect some soft particles which would die in the lead (to be optimized with the ongoing simulation)

Some passive material could also be introducedamong the scintillator layers for a better containement, probably we will have to put an absorber in between the veto and neutron detector in order not to reject interesting events

Pb, in this case put at the beginning

ECC

np

Backward Neutron detectorEff=60%

50 planes of8 strips 20 cm

400 channels

The Si tracker can be recycled from a CMS prototype

The ECAL can be recycled from NOMAD lead-glass prototypes

The trigger will be based on the ECAL + VETOIn order to isolate the interactions really happening in the brick instead than in the ECAL or the neutron detector one has to look at the hit/tracks pattern in the Si tracker planes (check before the brick extraction)

The connection with the events measured with the MINOS DAQ (as for the SFT detector) will be done on the basis of the time-stamp

Conclusions: (Dario on April 23rd 2004)

First discussions with the MINOS/FNAL people have already been performed, Komatsu presentation at MINOS coll. Meet.We are writing, as requested by FNAL people, a MOU for this test which should be ready in a couple of weeks (about 10 pages) This document is needed for FNAL in order to establish the use of resources (space, time schedule, electrical power, manpower, infrastructures) and the potential impact on the other programs We are sorting out also the technical aspects related to MINOS (timestamp, B field) The emulsion processing capabilities at FNAL have to be reactivated On a long time scale some collaboration from local people (DONUT) to run the test is needed This test can be quite useful for OPERA to learn about neutrino interactions in the bricks in a controlled way

The End

Documents

Physics coordination meeting summary report Emulsion simulation: GenIma Update of brick finding analysis /e separation: test beam analysis HE cosmic