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P326

s. d. n. n. P326. E. Iacopini, CSN1 Napoli 20 Sett. 2005. Abstract. Stato della Collaborazione (A. Ceccucci) Disegno dell’apparato sperimentale (N. Doble, L. Gatignon) Stato della simulazione (G. Ruggiero) Dove siamo con i detectors.

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P326

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  1. s d n n P326 E. Iacopini, CSN1 Napoli 20 Sett. 2005

  2. Abstract • Stato della Collaborazione • (A. Ceccucci) • Disegno dell’apparato sperimentale • (N. Doble, L. Gatignon) • Stato della simulazione • (G. Ruggiero) • Dove siamo con i detectors

  3. Proposal submitted to SPSC on June 11, 2005: “We propose to measure the very rare decay K+ p+nnat the CERN SPS to make a decisive test of the Standard Model by extracting a 10% measurement of the CKM parameter |Vtd|.” • The open presentation to the SPSC is scheduled on September 27, 2005

  4. Recent developments in the rare kaon decay community • A few months ago the Fermilab Directorate endorsed the PAC recommendation not to pursue K+ p+nn at the Main Injector The physics of K+ p+nn was considered very important but a potential conflict for protons between the kaon and the neutrino possible programmes at Fermilab lead to this recommendation • Very Recently the RSVP program was terminated: • The m to e conversion experiment (MECO) and the K0 p0nn experiment, ready to start construction at BNL, will not be built • This leaves CERN and Japan (JPARC) as the only places where an ultra-rare kaon decay experiments are currently envisaged • However, to be completely fair, one should also mention: • Plans at Protvino as mentioned at KAON2005 • Plans at Frascati to study KS at an upgraded phi factory

  5. Strengthening P326 • The demise of the US kaon program has triggered negotiations with members of KOPIO/CKM to join P326 • The following groups have signed up since the proposal submission: • S Louis Potosi (Mexico, J. Engelfried) • Bolotov’s group (Moscow, INR) • Interest to join has been expressed by the following groups: • Fermilab (P. Cooper) • BNL (L. Littenberg) • British Columbia (D. Bryman) • However, a possible participation of US groups is subject to: • DOE support towards a strong contribution to the construction of the detector (notably the RICH counter) • The involvement of US Universities in addition to National Labs (at least for BNL)

  6. Endorsement of P326 R&D by SPSC • From the draft minutes of the July 05 meeting: "The SPSC considers it important that an R&D programme continues concerned with the possibility of an experiment to measure the rare decay K+p+n n"

  7. CERN Program and Plans introduction to Round Table discussion on The Future of High Energy Physics ECFA-EPS Joint Session at HEPP-EPS 2005 International Europhysics Conference on High Energy Physics Lisbon, July 21 -27, 2005 Jos Engelen CERN

  8. From Medium Term Plan, CERN/2615 • Will determine the future course of high energy physics • Detector completion/upgrade/in particular for luminosity upgrade ( 1035) • (~2014); requires R&D, machine and detectors • Very limited neutrino programme (in scope) • New initiatives include K++; why not K00..? • New initiatives may include a long term neutrino programme • CERN working groups Proton Accelerators for the Future (PAF) • and Physics Opportunities at Future Proton Accelerators (POFPA) • New initiatives to appear in Budget Plan from 2006 (or maybe 2007) • onwards EURISOL Design Study (including beta beams) • Accelerator R&D includes EU funded networks, joint projects, design • studies • Linear colliders: Eurotev (‘generic’) and CLIC (CERN and partners, • ‘collaboration’, feasibility proof by 2009) No fully-fledged Neutrino Factory Design Study yet (2008 if EU support)

  9. P326 oggi Slides from Niels Doble & Lau Gatignon

  10. Choice of K+ momentum: (for 400 GeV/c proton momentum)

  11. (2 RMS)

  12. Il Detector 1.5 p+ K+ n n 800 MHz (p/K/p) 10 MHz Kaon decays Solo i rivelatori upstream sono esposti a 800 MHz di fascio (8.6% K) …

  13. Il RICH ...

  14. La simulazione MC del fondo e del segnale Thanks to Giuseppe Ruggiero

  15. Background kinematically constrained 92% of total background p+p0 forces us to split the signal region

  16. Background not kinematically constrained Spoils the signal region 8% of total background

  17. Background rejection • Goal of P326: S/B ≈ 10~10-12 rejection • 2-steps background rejection: 1) Kinematical rejection • Region I: 0 < m2miss < 0.01 GeV2/c4 Against Km2, p+p0 • Region II: 0.026 < m2miss < 0.068 GeV2/c4 Against p+p0, p+p+p-, p+p0p0 2) Veto and Particle ID • g, m, charged particles • m – p - e separation

  18. Sources of background Simulated using Flyo Simulated using GEANT4 Simulated using Flyo • Kinematical rejection inefficiency • Resolution effects • Non gaussian tails • Beam pile – up • Veto and particle ID inefficiency • RICH • m – veto • g – veto Simulation (Jurgen) Simulation(Oleg) Parameterization(Simulation in progress by Rome) (Data in progress: LKr by NA48/2, ANTI by Frascati)

  19. Resolutions (Flyo MC) • Results: • s(PK)/PK = 4.2 x 10-3 • s(qK) = 16.7 mrad • s(Pp)/Pp = 0.23% + 0.005% Pp (GeV/c) • s(qpK) = 60 – 20 mrad (Pp = 10 – 50 GeV/c) • Gigatracker • 300 x 300 mm pixels • 0.4% X0 per Spibes • Simple reconstruction • 2% inefficiency per station • Double Spectrometer • 80mm resolution in X and Y hits (125 mm per view) • 0.5% X0 per chamber • Track momentum from fit • Angle from first 2 chambers • Fully efficient p+p0 m2miss resolution qpK qK qp PK Ptrack

  20. Veto and particle ID • g – Veto: • g inefficiency parameterization • RICH (Simulation by Jurgen): • 17 m long, 1.0 atm Ne • m – Veto (Geant4 simulation by Oleg): • hm-veto = 10-5 JURGEN

  21. Some general remarks … • Kaon Flux: 4.8×1012 decay/year in the fiducial region • Detector Layout as described in the proposal: • Straw chambers 5cm inner radius displaced in x, according to the positive beam deflection in the spectrometers • Magnets of the double spectrometer: MNP33 – 1 Ptkick = 270 MeV/c MNP33 - 2 Ptkick = -360 MeV/c • All the expected background given per 1 year of data taking

  22. Selection (1) • Number of tracks • 1 positive downstream track (hit in all the 6 chambers) • Choice of the upstream track using minimum c2 (Dt, cda) • Detector geometry • Downstream track inside of the detector acceptance: • Straws: 10 cm < Rtrack < 85 cm (centered on the hole of the chamber) • RICH: 12 cm < Rtrack < 120 cm (both on front and back surfaces) • LKr: Octagonal outer shape and Rtrack > 15 cm • MAMUD: square shape, 260x260 cm outer, 36x30 cm inner (front and back) • Particle ID • Not muons in RICH or MAMUD • Not electrons in RICH or LKr (LKr with 10-3 inefficiency of e – ID)

  23. Selection (2) • Fiducial decay region • 5 m < Zvertex < 65 m (from the final collimator, Zvertex defined as the Z coordinate of the point closest to both the tracks) • Cut on momentum • 15 GeV/c < Ptrack < 35 GeV/c • Specific cuts • DPtrack/Ptrack < 2.5×s(P)/P (against the not gaussian tails) • CDA < 0.8 cm (against the tails from the beam pile – up) • Kinematics • REGION I: 0 < m2miss < 0.01 GeV2/c4 • REGION II: 0.026 < m2miss < 0.068 GeV2/c4

  24. m+ n • Acceptance after all the cuts: Acc=(8 ± 2) × 10-6 • Same procedure as for p+p0 to extract the acceptance • Muon veto inefficiency: • hMAMUD(m) = 10-5 (MAMUD) • hRICH(m) = 5 × 10-3 (RICH) (conservative) • Assumption:MAMUD and RICH rejection inefficiencies independent • Expected events: N(Km2) = Fkaon × BR × Acc × hRich(m) × hMAMUD(m) =(1.2 ± 0.3) / year • Region I:1.1 / year • Region II:<0.1 / year • Nngaus ~ 0.4 / year, Npileup ~ 0.8 / year

  25. p+p0 • Acceptance after all the cuts: Acc = (1.3 ± 0.1) × 10-4 • Assumption: independence between kinematical rejection inefficiency (hkin) and selection acceptance • NI,II = hkin×Nsel(Flyo)+Npileup(Flyo) • NI,II = Number of expected events in regions I and II after all the cuts • Nsel(Flyo) = number of events selected in Flyo before the cut on m2miss • Npileup(Flyo) = number of events in Regions I and II due to the beam pileup • Acc =NI,II / Ngen(Flyo) • Photon veto inefficiency: • h(p0) = 2 × 10-8 • Expected events: N(p+p0) = Fkaon × BR × Acc × h(p0) =(2.7 ± 0.2) / year • Region I:1.7 / year • Region II:1.0 / year • Nngaus ~ 0.5 / year, Npileup ~ 2.2 / year

  26. Two body background vs Spibes performances 2 body background events 2 body background events Total Total p+p0 p+p0 Km2 Km2 s(t) Spibes ns h Spibes ineff

  27. Other backgrounds • Ke3: • Acceptance ~12% (Flyo) • hp0 ~ 3×10-8 • Positron ID: hLKr × hRICH < 10-3 × 10-3 (conservative) • NEGLIGIBLE • Km3: • Acceptance ~17% (Flyo) • hp0 ~ 3×10-8 • Muon ID: hRICH × hMAMUD < 10-5 × 10-2 (conservative) • NEGLIGIBLE • p+p0p0: • High suppression from kinematics and g veto • NEGLIGIBLE

  28. Signal Acceptance • Selection applied on pnn events generated with FF (from CMC) • Effects not taken into account: • Random veto • Accidental loss due to hit multiplicity cuts • Straw inefficiency • Loss due to cuts in MAMUD for muon ID • BR(p+nn)=8×10-11 (SM)

  29. Signal Acceptance • Results • REGION I: (4.10 ± 0.03) × 10-2 • REGION II: (12.88 ± 0.05) × 10-2 • Total: (16.98 ± 0.06) × 10-2 • Acceptance normalized in the region: 5 m < Zvertex < 65 m • Most important cuts • Ntrack=1: cuts 8% of events • Geometry: cuts 10% of events • Momentum: cuts 50% of events • Pile – Up: cuts 12% of events

  30. Signal and backgrounds / year

  31. Responsabilità

  32. Tentative sharing of construction responsibility (sept. 05) • Beam Line (CERN) • CEDAR (CERN) • GIGATRACKER (CERN, INFN, Saclay [kabes]) • VACUUM TANK (Common fund) • ANTI Counters (INFN) • STRAW TRACKER (DUBNA, MAINZ) • MNP33/2 (Common Fund) • CHOD (INFN) • RICH (US? + Mexico) • LKR (CERN+INFN) • MAMUD (INR+Protvino) • SAC + IRC (Sofia) • Trigger & DAQ (CERN+INFN+?) A. Ceccucci August 31 2005 - Cambridge

  33. Come contiamo di procedere ... • Abbiamo, molto schematicamente, due problemi: • Politico: • la Collaborazione ha bisogno di rinforzarsi. • Ci sono stati notevoli passi in avanti nel 2005, come discusso • all’inizio, e comunque noi continueremo su questa strada … • Tecnico: • siamo in grado di installare i rivelatori che ci servono? • Per questo abbiamo un programma di R&D per tutti i nuovi rivelatori • e per validare quanto resta dei vecchi (il LKr …)

  34. R&D 2006: Il Run ... Il 27 settembre, verrà presentata all’SPSC, insieme alla Proposta P326, una contestuale richiesta di 30 gg di run per il 2006, sulla solita linea di fascio K12, principalmente per  - misurare l’inefficienza di osservazione dei fotoni con il LKr  - misurare il fondo da p/K interagenti con il gas residuo  - determinare l'alone del fascio  - effettuare i tests necessari sui prototipi dei nuovi rivelatori (Cedar, hodo, sensori gigatracker …)

  35. R&D sui rivelatori di nostra pertinenza: Hodoscopio Veto dei g Gigatracker

  36. The fast hodoscope FI-PG L’idea è quella di usare Glass Multigap RPCs, sullo stile di quanto realizzato in ALICE A questo rivelatore infatti è richiesto di essere efficiente (>99%) e di avere un’ottima risoluzione temporale (50ps) in modo da ridurre al massimo la possibilità di associazioni accidentali fra il pione di decadimento ed il K che lo origina.

  37. ALICE detector layout • 13x120 cm2 area for each module • 7x120 cm2 active area for each module • 2 anode and 1 chatode PCB with picup pads • 5+5 250 mm gaps filled with gas mixture • 1 cm honeycombs panel for mechanical stability • 96 pads per module readout with 32 flat cable • Differential signal send to interface card • Greater number of gaps • Lower HV (+6.5 kV, -6.5 kV) • Signal amplitude greater of a factor 2

  38. Front-End electronics ALICE has developed for this purpose, fast (1ns peaking time) front-end amplifier/discriminator (NINO). Each NINO can handle 8 channels. The input is low impedance (40-75 Ω) differential, and the output standard is an open-collector LVDS (Low Voltage Differential Signal). NINO can respond to another signal immediately (few ns) after the end of a previous signal (almost no dead time). On each front end card 3 NINO chip are mounted so the card can handle 24 channels The NINO ASIC bonded to the PCB

  39. MRPC performance Efficiency > 99%Time resol. < 50 ps Test performed with the ALICE TOF rate 50 Hz

  40. Rate tests at GIF • The MRPC were tested for efficiency up to a rate of 1.6 kHz • The performance seem to be stable only using an effective voltage of 11.4 kV • The MRPC were tested for time resolution up to a rate of 1.6 kHz • The time resolution seem to decrease a little bit • The resolution at 1.6 kHz is well above 100 ps • This performance are very suitable for P326 • New high rate test are mandatory to validate performance up to 5 kHz

  41. Ageing test at GIF Irradiation with 7∙109 particles/cm2 • The performances seem to remain stable in time • The total amount of irradiated charge is equivalent to only 140 days of P326 run:

  42. Signal electrode Cathode -10 kV (-8 kV) (-6 kV) (-4 kV) (-2 kV) Anode 0 V Signal electrode G MRPC for P326 We stick as much as we can to the Alice design, however to reduce material, we are planning a single stack layer. The time resolution, according to experts, should go from ~40 ps to ~80 ps

  43. The new PCB for P326 • The PCB design used by ALICE is not suitable for P326: • The connectors on each side introduce too much dead space between two modules • It’is very difficult to bring signals out of the detector using ALICE configuration • The material budget would not be uniform due to connectors and cables • We are working on a new PCB layout, assuming • Connectors only at the end of each module • Each module is single-layer

  44. Where we are • Firstprototype assembly foreseen in late november • Cosmic ray test will be done, hopefully, within 2005 • Test of efficiency and time resolution at high rate • are mandatory to validate the possible use of such a • detector in P326: • test envisaged with NA48 test-run facility in 2006. • We are now investigating the possibility of • performing the rate test, using some existing ALICE • modulesat some beam facility, to be found.

  45. The gamma veto

  46. Il LKr ... • Must achieve inefficiency < 10-5 to detect photons above 1 GeV, and this has to be tested in 2006. • It has also to be evaluated the effect on the inefficiency of the material in front of the calorimeter (RICH, hodoscope, windows, etc) • Advantages: • It exists • Homogeneous (not sampling) ionization calorimeter • Very good granularity (~2 2 cm2) • Fast read-out (Initial current, FWHM~70 ns) • Very good energy (~1%, time ~ 300ps and position (~1 mm) resolution • Disadvantages • 0.5 X0 of passive material in front of active LKR • The cryogenic control system needs to be updated • Needs a new readout

  47. Large angle vetoes LNF, NA, PI, RM1 The detector must be able to veto p0s, with energy in the range 40-65 GeV, at the 10-8 level. This means that it must possess an average veto power on the single photon of the order 10-4 • Two technologies are to be compared: • Tiles a la CKM • Spaghetti a la KLOE • Extensive Geant4 simulation started to study both solutions as far as punch-through, inefficiency dependence from the hitting angle, energy and position, … are concerned. • But also to be compared • Costs • Mechanical design of the support …

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