1. Summary Detector Working Group Neutrino Factory International Design Study Meeting 17 January 2008 Paul Soler

2. 2 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Contents o MIND summary and tasks –Synergy with TASD: develop common software (TASD performance covered by Walter for low E Neutrino Factory) o Near Detector summary and tasks o Note: no discussion of silver detectors

3. 3 Neutrino Factory International Design Study Meeting RAL 17 January 2008 MIND iron (4 cm) scintillators/RPCs (1cm) beam 100 m 14 m B=1 T 1cm transverse resolution M~100 KTon Easy to detect muons in iron by range Easy to discriminate against hadron showers Based in known technology: ~MINOS Can be very massive Cost is not prohibitive: 300-400 M$ Easy to magnetise iron cannot detect electrons or taus the energy threshold is high

4. 4 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Simulation and resolution Including QE Essential to measure the oscillation pattern Crucial to solve degeneracies Fully contained muons by range Scaping muons by curvature Hadron shower: EE E had Detector effects not simulated Perfect pattern recognition Reconstruction based on parameterisation Dipole field instead of toroidal field

5. 5 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Kinematic cuts

6. 6 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Charge identification Simple exercise. Assumptions: No border effects Non-gaussian scatters can be identified via local χ 2 criterion with a Kalman Filter Assume gaussian MS Gluckstern formula + MS term B Fe =1.25 T 1.7 T 2T Event simulation Realistic flux Non-gaussian MS Border effects LSQ fit L  >150 cm L  >75 cm

7. 7 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Wrong charge assignments

8. 8 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Backgrounds

9. 9 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Signal efficiency Old analysis II: P  >5 GeV, Q t > 0.7 GeV Old analysis I: P  >7.5 GeV, Q t > 1 GeV  CC signal Efficiency plateau between 5 and 8 GeV depending on L μ cut L  > 75 cm L  >150 cm L  >200 cm baseline: L μ > 150 cm Ensures charge mis-ID below 10 -3

10. 10 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Aims of full simulation/reconstruction Demonstrate that for E < 10 GeV Backgrounds are below 10 -3 The efficiency can be increased with respect to fast analysis Compute: Signal and backgrounds efficiency as a function of energy Energy resolution as a function of energy Identify crucial parameters to be optimised to maximise the sensitivity to the osc. parameters Optimise segmentation and B field based on the above parameters and taking into account feasibility and cost

11. 11 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Hadron shower The hadron shower energy and angle are smeared according to MINOS proposal + MINOS CalDet + Monolith testbeam Hadrons are stopped when they decay or undergo a nuclear interaction We then record their energy and momenta: p 1, p 2,..., E 1,E 2,... Their length is also recorded: L 1, L 2,... Fast analysis

12. 12 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Muon Muon is followed until it stops, decays or escapes the detector The position of all hits is recorded And also its 3-momentum  Muon hits are smeared with 1cm transverse resolution A track fit gives its charge For the kinematical analysis the muon momentum is smeared according to Gluckstern formula + MS term Fast analysis

13. 13 Neutrino Factory International Design Study Meeting RAL 17 January 2008 In real life The muon is not isolated: pattern recognition 2 independent views XZ and YZ that should be matched The event sense can be computed from timing (?)

14. 14 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Muon reconstruction  1.Reconstruct the vertex from event topology 2.Cellular automaton or Hough transform for planes with small activity 3.Match X and Y views in planes with small activity 4.Find approximate muon parameters based on these planes and vertex 5.Incremental Kalman Filter from the end of the track towards vertex Multiple scattering, energy loss and B field map Recon vertex Cellular automaton Kalman filter

15. 15 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Steps

16. 16 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Event generation Only DIS interactions as coming from LEPTO has been generated so far Including QE and RES should have a big impact at low neutrino energies: No hadron shower: Easy pattern recognition Better neutrino energy resolution Help in improving the threshold energy and reduce backgrounds Generators: Nuance, Neut, Neugen, Genie

17. 17 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Synergies with TASD Scintillator bars, PD and electronics are the same. This is the most difficult part B field production is different and more difficult A common framework for simulation and reconstruction (M. Ellis) 15 m 100 m

18. 18 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Detector optimisation: Longitudinal segmentation

19. 19 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Detector optimisation: Transverse segmentation Assuming perfect pattern recognition 1 cm transverse resolution is enough for charge and Q t measurements Pattern recognition: better segmentation should improve it which resolution saturates the patter recognition performance ? Lines: 1, 1.5 and 2 GeV/c muon momentum B Fe =1.25 Tesla Fe thickness = 4 cm B Fe =1.25 Tesla Fe thickness = 2.5 cm B Fe =2 Tesla Fe thickness = 2.5 cm

20. 20 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Detector optimisation: magnetic field Even if we are able to isolate a 1 GeV/c muon, the ratio curvature/MS is not sufficient. ~5% charge mis-ID The magnetic field strength is the crucial parameter Going from 1.25 to 1.7 Tesla average is feasible ( J. Nelson, Golden07 ) > 1 o.o.m improvement at 1 GeV/c. 10 -3 level 1 GeV/c 2 GeV/c 1.5 GeV/c MINOS MIND

21. 21 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Conclusions MIND Fast simulation/reconstruction was very useful until now But it’s time to move forward with a full simulation/reconstruction What are the main backgrounds at low energies ? What is the background level ? Where is the efficiency plateau ? What are the parameters to be optimised ? Prototyping program should go in parallel

22. 22 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Sim/Rec/Analysis task list Event simulation (NUANCE)--> bHEP1 converter between NUANCE and bHEP format Event transport (GEANT4) --> bHEP2 Geometry and bHEP interface Digitisation --> bHEP3 hits: 2D points, pulse height, time link to true particle Dummy digitisation with MIND fast simulation Reconstruction --> root file Build the framework: Define bHEP format Read dst (bHEP) Event likelihood Cellular automaton (import from T2K) Kalman filter (RecPack) Identified manpower for these tasks In Valencia/Brunel/Glasgow + EuroNu manpower Tasks to be done in parallel

23. 23 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Beam Diagnostics and Near Detector aims o Beam diagnostics (needed for flux measurement) –Number of muon decays –Measurement of divergence –Measurement of Muon polarization o Near detector measurements needed for neutrino oscillation systematics: –Flux control for the long baseline search. –Measurement of charm background –Cross-section measurements: DIS, QES, RES scattering o Other near detector neutrino physics (electroweak and QCD): –sin 2  W -  sin 2  W ~ 0.0001 –Unpolarised Parton Distribution Functions, nuclear effects –Polarised Parton Distribution Functions – polarised target –Lambda (  ) polarisation –  S from xF 3 -  S ~0.003 _ –Charm production: |V cd | and |V cs |, CP violation from D 0 / D 0 mixing –Beyond SM searches –…

24. 24 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Beam Diagnostics o Beam Current Transformer (BCT) to be included at entrance of straight section: large diameter, with accuracy ~10 -3. o Beam Cherenkov for divergence measurement? Could affect quality of beam. storage ring shielding the leptonic detector the charm and DIS detector Polarimeter Cherenkov BCT

25. 25 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Beam Diagnostics o Muon polarization: Build prototype of polarimeter Fourier transform of muon energy spectrum amplitude=> polarization frequency => energy decay => energy spread.

26. 26 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Flux Measurement at Near Detector  Best possibility: Inverse Muon Decay: scattering off electrons in the near detector. Known cross-sections

27. 27 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Near Detector used to extract P e  o Use matrix method with Near Detector data (even if spectrum not identical in near and far detector!) to extract oscillation probability:  Where: M 1 =matrix relating event rate and flux of e at ND M 2 =matrix relating event rate and flux of  at FD M=matrix relating measured ND e rate and FD  rate M nOsc =matrix relating expected e flux from ND to FD o Method works well but need to extract syst errors of method: Probability of oscillation determined by matrix method under “simplistic” conditions. Need to give more realism to detector and matter effects.

28. 28 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Charm measurement o Motivation: measure charm cross-section to validate size of charm background in wrong-sign muon signature o Charm cross-section and branching fractions poorly known o Semiconductor vertex detector only viable option in high intensity environment (emulsion too slow!)

29. 29 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Cross section measurements o Measure of cross sections in DIS, QE and RES.  Coherent  o Different nuclear targets: H 2, D 2 o Nuclear effects, nuclear shadowing, reinteractions At NUFACT, with modest size targets can obtain very large statistics, but is <1% error achievable? What is expected cross- section errors from MiniBoone, SciBoone, T2K, Minerva, before NUFACT?

30. 30 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Other physics: Parton Distribution Functions o Unpolarised and Polarised Parton Distribution Functions o  S from xF 3 -  S ~0.003 o Sum rules: e.g. Gross-Llewelyn Smith   polarization: spin transfer from quarks to  — NOMAD best data — Neutrino factory 100 times more data

31. 31 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Near Detector Design Muon chambers EM calorimeter Hadronic Calorimeter o Overall design of near detector(s): –Near Detector could be a number of specialised detectors to perform different functions (ie. lepton and flux measurement, charm measurement, PDFs, etc.) or larger General Purpose Detector

32. 32 Neutrino Factory International Design Study Meeting RAL 17 January 2008 Near Detector Conclusions o Near Detector considerations: optimisation design –Vertex detector: Choice of Pixels; eg. Hybrid pixels, Monolithic Active Pixels (MAPS), DEPFET; or silicon strips –Tracker: scintillating fibres, gaseous trackers (TPC, Drift chambers, …) –Other sub-detectors: PID, muon ID, calorimeter, … o Tasks: –Simulation of near detector and optimisation of layout: could benefit from common software framework for Far Detector –Flux determination with inverse muon decays, etc. –Analysis of charm using near detector –Determination of systematic error from near/far extrapolation –Expectation of cross-section measurements –Test beam activities to validate technology (eg. vertex detectors) –Construction of beam diagnostic prototypes –Other physics studies: PDFs, etc. (engage with theory community for interesting measurements)