Paul Scherrer Institut Open Users Meeting BV43 February 22, 2012

Transcription

1 Nw Exprimntal Sarch for μ Paul Schrrr Institut Opn Usrs Mting BV43 Fbruary 22, 2012 André Schöning for th Mu3 Collaboration 1

2 Lpton Flavor Violating Dcay μ+ ++SUSY Exotic Physics 2

3 Lpton Flavor Violating Dcay μ+ ++SUSY Exotic Physics Currnt xprimntal limit: B( μ+ ++- ) < (90%CL, SINDRUM 1988) Our ultimat Goal: B( μ+ ++- ) < (90% CL xclusion) B( μ+ ++- ) ~ (5 sigma discovry) 3

4 1. Motivation 2. Thory 3. Exprimntal Situation 4. Th dcay μ 5. Th novl xprimnt 6. Timtabl + Costs 4

5 LFV in th Standard Modl SM procss via Nutrino mixing Nutrino Oscillation Summary Plot procss is havily supprssd du to small mass diffrnc of nutrinos! B( μ+ ++- ) <<

6 Byond th Standard Modl Lpton Flavor Violation prdictd by many Nw Physics modls: Suprsymmtry Higgs Triplt Modls Littl Higgs Modls Nw Havy Vctor bosons (Z') Lptoquarks (GUT modls) Extra Dimnsions (KK towrs) Nutrino Oscillation Summary Plot In many modls obrvabl LFV ffcts ar xpctd, rlatd to th mixing larg obsrvd in lpton sctor B( μ+ ++- ) ~ possibl 6

7 Effctiv clfv Lagrangian Effctiv chargd LFV Lagrangian (Y. Kuno and Y Okada): dipol coupling Tnsor trms (dipol) μ.g. Suprsymmtry ~ ν ~ ν χ tr diagram Four-frmion trms μ (scalar) H, Z' (vctor).g. Higgs, Z' 7

8 Effctiv clfv Lagrangian Effctiv chargd LFV Lagrangian (Y. Kuno and Y Okada): dipol coupling Tnsor trms (dipol) μ.g. Suprsymmtry ~ ν ~ ν χ tr diagram Four-frmion trms μ (scalar) H, Z' (vctor).g. Higgs, Z' 8

9 Effctiv clfv Lagrangian Effctiv chargd LFV Lagrangian (Y. Kuno and Y Okada): dipol coupling Tnsor trms (dipol) μ mμ.g. Suprsymmtry 2 Λ (1+κ) H dipol χ μ (scalar) H, Z' (vctor) ~ ν tr diagram Four-frmion trms.g. Higgs, Z' ~ ν μ ν, κ J ν J 2 Λ (1+κ) 9

10 Effctiv Modl Comparison Effctiv clfv Lagrangian: mμ L= 2 H dipol + 2 κ J νμ J ν, Λ (1+κ) Λ (1+κ) μ ~ ν χ ~ ν κ=0 Λ / μ H, Z' = 1/ κ κ= = ffctiv mass scal (including coupling) 10

11 μ+ ++- vrsus μ+ +γ Effctiv clfv Lagrangian: mμ L= 2 H dipol + 2 κ J νμ J ν, Λ (1+κ) Λ (1+κ) μ ~ ν ~ ν χ μ ~ ν χ H, Z' = 1/ κ κ= κ=0 ~ ν / μ γ - Mu3 snsitiv to additional diagrams! 11

12 μ+ ++- vrsus μ+ +γ Effctiv clfv Lagrangian: mμ L= 2 H dipol + 2 κ J νμ J ν, Λ (1+κ) Λ (1+κ) Phas II Phas I κ= κ=0 12

13 Exampl: Higgs Triplt Modls M.Kakizaki t al., Phys.Ltt. B , 2003 ν νµ ντ 13

14 Exampl: Higgs Triplt Modls M.Kakizaki t al., Phys.Ltt. B , 2003 ν νµ ντ ν νµ ντ sin2 2θ13= 0.085±0.029(stat)±0.042(syst) (acclrator and ractor) 14

15 Exprimntal Situation 15

16 Backgrounds Irrducibl BG: radiativ dcay with intrnal convrsion - ν ν B(μ νν) = i i 16 E i = mμ p i = 0

17 Backgrounds Irrducibl BG: radiativ dcay with intrnal convrsion - ν + missing nrgy from two nutrinos ν B(μ+ R.M.Djilkibav, R.V.Konoplich PRD79 (2009) νν) = stply falling! vry good momntum and total nrgy rsolution rquird! 17

18 Accidntal Backgrounds Combinatorial Background (Pil up): Two muon dcays 2 x (μ+ + νν) and on fak (wrong charg: rconstruction, Bhabha, back-curling + - ) Radiativ dcay with intrnal convrsion μ+ (+) +- νν ovrlayd with muon dcay μ+ + νν (+) + Combinatorial BG can b largly rducd by imposing prcis timing (TOF) prcis vrtxing prcis kinmatics 18 +

19 History Sindrum (NP B299 1, 1988) σp/p (50 MV/c) = 5.1% σp/p (20 MV/c) = 3.6% σθ (20 MV/c) = 28 mrad VTX: σd= ~ 1mm X0(MWPC) = 0.08% % pr layr B( μ+ ++- ) < (90%CL) B = bam S = solnoid M = magnt C = multiwir proportional chambr H = hodoscop Mu3: factor ~10 bttr spatial and kinmatic rsolution high rat of muons/s on targt B( μ+ ++- ) <

20 Tracking - Tchnology Choic Tracking dtctors High rats and aging ffcts prohibitiv for gasous dtctors Solid stat dtctors Prcis spatial rsolution for vrtxing and momntum rconstruction Silicon pixl snsor Momntum rsolution dominatd by multipl scattring in rang of intrst (~10-53 MV ): 1 Θ MS P X / X0 Vry thin silicon pixl snsor 20

21 Momntum Rsolution I Momntum rsolution givn by (linarisd): multipl-scattring angl Θ MS MS Ω σ p Θ MS Ω P prcision rquirs larg lvr arm (larg bnding angls Ω) B 21

22 Momntum Rsolution II Momntum rsolution for half turns givn by: Θ MS σp O(Θ2MS ) P MS Ω π bst prcision for half turns dsign tracking dtctor for masuring rcurlrs B 22

23 Exprimntal Proposal 23

24 Mu3 Baslin Dsign Long cylindr! not to scal ~150 cm ~15 cm Gomtrical accptanc ~70 % for μ+ ++- dcay 24

25 Mu3 Baslin Dsign Long cylindr! not to scal ~150 cm ~15 cm Gomtrical accptanc ~70 % for μ+ ++- dcay 25

26 Silicon Pixl Dtctor Tchnology Choic High Voltag Monolithic Activ Pixl Snsors (HV-MAPS) high prcision pixls 80 x 80 μm2 (27 x 40 μm2 currntly in tst) can b thinnd down to 30 μm (~ X0) low production costs (standard HV-CMOS procss, 60V) activ snsors small RO bandwidth, no bump bonding rquird triggrlss and fast radout low powr 26

27 High Voltag Monolithic CMOS Pixl transistor logic mbddd in N-wll ( smart diod array ) Nw Tchnology! I.Pric, P. Fischr t al., NIM A 582 (2007) 876 (ZITI Mannhim, Uni Hidlbrg) Snsors tstd succssfully: low nois: S/N = radiation tolrant high fficincy 27

28 Pixl Dtctor Hardwar and Tsts Univrsity Hidlbrg: ZITI Mannhim / Physikalischs Institut prototyp 180 nm Plan: construct barrl prototyp in 2012 flxibl kapton print 25 mu Support structur 25 mu Kapton 28

29 Pixl: Radout Frams 50 ns 100 muon rat muon stops/s Intrinsic timing rsolution of silicon pixl: <50 ns 29

30 Pixl: Radout Frams 50 ns 100 muon rat muon stops/s additional Tim of Flight (ToF) dtctors rquird < 1ns 30

31 Mu3 Baslin Dsign not to scal ~100 ps ~1ns Scintillating tils and fibrs (Univrsitis Gnva + Zurich) 31

32 Scintillating Fibr Trackr high spatial rsolution for unambiguous assignmnt of silicon hits: scintillating fibrs: x-y plan: Ø = μm fibrs photosnsor Hamamatsu MPPC arrrays (SiPM) high gain >105, high frquncy > 1MHz tim rsolution <1 ns prototyp plannd for summr 2012 Hamamatsu MPPC 5883 T. Nakada t al. EPFL / Aachn (in collaboration with EPFL (Nakada t al.)) 32

33 Scintillating Tils scintillating tils of siz ~ 1 cm2 timing rsolution of ~100 ps light guids photosnsor (SiPM) Timing information from tils and scintillating fibrs will hlp to rduc accidntal backgrounds and as track rconstruction 33

34 ToF Radout + Nw DRS5 Chip DRS4 chip (PSI) switchd capacitor chip 8+1 Channls 700 MS/s- 5 GS/s Nw DRS5 chip (PSI) first prototyp mid MHz continuous hit rat considrd for Mu3 - ToF radout 34

35 Muon Stopping Targt not to scal ~10cm Sindrum-lik xtndd targt hollow doubl con targt (.g. 90 µm Al) 35

36 Muon Stopping Targt Pixl dtctor: vrtx rsolution ~ 120 μm supprssion of accidntal BG Sindrum-lik xtndd targt hollow doubl con targt (.g. 90 µm Al) 36

37 DAQ and Onlin Filtr Farm Data Acquisition: pixl dtctor: numbr of (zro supprssd) channls 250 million pr 50 ns radout fram ~2000 hits fibr trackr: numbr of (zro supprssd) channls about 10k for muon stop rat of ~2 109 (2 108) muons pr scond raw data rat ~ 150 (15) Gbyt/s (larg but smallr than at LHC) 37

38 DAQ and Onlin Filtr Farm Onlin softwar filtr farm continuous front-nd radout (no triggr) FPGAs and Graphical Procssor Units (GPUs) onlin track (vnt) rconstruction data rduction by factor ~1000 on tap ~ 100 Mbyt/s 38

39 Magnt: gradint or no gradint? Simulation Rsults for Baslin Dsign: 11 hits pr lctron gradint fild 17 hits pr lctron homognous fild MEG targt homognous B-fild curlr Spd of Track Rconstruction: homognous fild allows for fast non-itrativ analytical calculation rconstruction spd important for onlin filtring! Homognous magntic fild of about Tsla prfrrd 39

40 Bamlin Phas I Scnarios at bamlin π5 MEG and Mu3 could co-xist if MEG is to b upgradd MEG πe5-part 40

41 Bamlin Phas I Scnarios at bamlin π5 MEG and Mu3 could co-xist if MEG is to b upgradd MEG πe5-part schmatical sktch only! 41

42 Bamlin Phas I Scnarios at bamlin π5 MEG and Mu3 could co-xist if MEG is to b upgradd MEG πe5-part muon rats of /s achivd in past factor ~2 mayb possibl by mans of optimisations of E targt muons/s rat of 2 108/s sufficint to rach B( μ+ ++- ) < (90%CL) in 3 yars ( corrsponds to ~ B( μ+ +γ) < (MEG)) 42

43 Bamlin Phas II Nutron Sourc SINQ: SINQ SINQTargt Targt Protons Protons SINQ SINQ protons Muon rats in xcss of 1010 pr scond in bam phas accptanc possibl First simulations confirmd calculations muons muons/s ndd to rach ultimat goal of B( μ+ ++- ) < Not bfor

44 Status Simulations GEANT4 simulations, work in progrss: dtrmination of occupancis tst track rconstruction ff. and rsolution background studis Prliminary Rsults: muon stop rat of xprimntally possibl most svr BG is μ+ ++- νν rquird rsolutions can b achivd Snsitivity limit from μ+ ++- νν μ

45 Mu3 Scnarios Phas I and II Phas I ( ) Phas II (>2017) 3 yars 3 yars total tim in sconds 3.0E E+007 muon rat [pr scond] 2.0E E+009 accptanc track finding fficincy prong fficincy vnt slction ff total fficincy #dcays 2.3E E+16 singl vnt snsitivity 4.3E E-17 90% xclusion limit 0.7E E-16 opration 45

46 Prliminary Cost Estimats from LOI u.a. = undr assssmnt Total cost stimat ~4 million CHF without bamlins 46

47 Proto-Collaboration Uni Gnva Uni Hidlbrg PSI Uni Zurich Also, in contact with ETH Zurich othr intrstd groups Plan: prpar a dtaild Rsarch Proposal within on yar 47

48 Backup 48

49 Radout Frams Th pixl dtctor radout is clockd at 20 MHz (50 ns) Intrinsic tim rsolution in silicon ns (to b xprimntally vrifid) Prcis timing providd by ToF is 0.2-1ns Dcay positrons sprad ovr up to 3 ns (rcurlr) ToF Tim structur of vnts in RO frams: n n+1 n+2 intrinsic pixl timing n+3 tim 49

50 Gomtrical Accptanc ~ 70% gomtrical accptanc 50

51 Two vrsus Thr Doubl Layrs cylindr radii 6 and 14 cm cylindr radius 8.5 cm mu3 dcay mu3 dcay 51

52 2D vrsus 3D tracking cylindr radius 7.5 cm cylindr radius 7.5 cm mu3 dcay mu3 dcay 52

53 Snsitivity and Background Limitation Rat of μ+ ++- νν as function of th nrgy rsolution: 99% 53 68% slction fficincy

54 Combinatorial Background Study intrnal convrsion and muon dcay Dsign Paramtrs: prob (vrtx coincidnc) = prob (tim coincidnc) = 0.1 ( muons pr scond) fak track and two muon dcays combinatorial BG can b ignord alrady for modrat nrgy rsolution σe < 3 MV vrtx and timing constraints not svr 54

55 Comparison: μ-dcay Exprimnts Sindrum 1988: σp/p (50 MV/c) = 5.1% σp/p (20 MV/c) = 3.6% σθ (20 MV/c) = 28 mrad VTX: σd= ~ 1mm X0(MWPC) = 0.08% % pr layr MEG 2010 (prliminary): σp/p (53 MV/c) = 0.7 % σφ (53 MV/c) = 8 mrad σθ (53 MV/c) = 8 mrad VTX: σr=1.4 mm, σz=2.5 mm Aim for similar or bttr angular and momntum rsolutions, high rats and bttr vrtx rsolution ~ 150 μm (combinatorial BG) 55

56 Multipl Scattring in Silicon Momntum rang p = MV multipl scattring! Exampl: p = 53 MV/c MEG: σθ MS= 8 mrad multipl scatt. pr layr X/X0=0.1% corrsponds to 90 μm Silicon μ : σθ MS= 5 mrad multipl scatt. pr layr X/X0=0.044% corrsponds to 40 μm Silicon Pixl snsors can b thinnd down to μm (xampls CMOS MAPS, DEPFET 50 μm) 56

57 Dtctor Accptanc μ + Modl Dpndnc: four frmion acc ~ 80% photon pnguin acc ~ 40% Minimum lctron nrgy: T-odd 4-frmion masur momnta in rang: p=15-53 MV/c dtrmins accptanc! 57