μ eee A novel experiment searching for the lepton flavour violating decay Niklaus Berger Physics Institute, University of Heidelberg

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1 A novl xprimnt sarching for th lpton flavour violating dcay μ Niklaus Brgr Physics Institut, Univrsity of Hidlbrg NuFACT, August 2011

2 Ovrviw Why sarching for lpton flavour violation? Whr can lpton flavour violation com from? Why do it in μ? How to rach a snsitivity of BR(μ ) < 10-16? Niklaus Brgr NuFact, August 2011 Slid 2

3 Why sarching for LFV In th Standard Modl, lpton flavour is consrvd Nutrino oscillations! What about chargd lptons? Chargd lpton-flavour violation through nutrino oscillations havily supprssd (BR < ) Clar sign for nw physics + W - γ * - ν µ ν µ - - Niklaus Brgr NuFact, August 2011 Slid 3

4 Whr to sarch for LFV? Lpton dcays μ γ μ τ lγ τ lll l = μ, τ lh Convrsion on Nuclus μn N Fixd targt xprimnts (proposd) LFV Mson dcays φ, K ll J/ψ, D ll Υ, B ll Collidr xprimnts p μ(τ) X (HERA) Z ll (LHC) 0,± χ ll X (LHC) N μn N τn μn τn Niklaus Brgr NuFact, August 2011 Slid 4

Exprimntal Status Purly lptonic LFV BR(μ γ) < 2.

5 Exprimntal Status Purly lptonic LFV BR(μ γ) < (MEG) < (MEG, projctd) BR(τ (μ)γ) <~ (B-Factoris) BR(μ ) < (SINDRUM) < (This talk) BR(Z μ) < 10-6 (LEP) arxiv: Smi-hadronic LFV BR(K πμ) <~ BR(μN N) <~ (SINDRUM 2) <~ (DM, projctd) < down to (projctd: Mu2, COMET, Prism) Niklaus Brgr NuFact, August 2011 Slid 5

6 Modls for LFV Modls for physics byond th standard modl oftn naturally induc LFV, ithr through loops or xchang of havy intrmdiats Suprsymmtric modls with GUT with Ssaw Modls with Lptoquarks Modls with additional Higgs particls Higgs triplt modl Modls with a Z or larg xtra dimnsions Niklaus Brgr NuFact, August 2011 Slid 6

7 Modls for LFV: SUSY ~ µ Suprsymmtry with slpton mixing ~ µ - χ ~ 0 - Lpton mixing is larg; would naturally xpct larg slpton mixing γ * - + Niklaus Brgr NuFact, August 2011 Slid 7

8 LFV with SUSY SO(10) GUT BR (τ µ γ ) Now SuprB SuprF µ γ vs. τ µγ at tanβ = 10 Mu3E PMNS θ 13 = 0 MEG Now For ths modls: BR(μ ) = BR(μ γ) Points: SUSY LHC paramtrs ( L. Calibbi, A. Faccia, A. Masiro, S.K. Vmpati, Phys.Rv. D74 (2006) ) CKM PMNS U 3 = 0.07 PMNS U 3 = 0 PMNS θ 13 = CKM BR (µ γ) Niklaus Brgr NuFact, August 2011 Slid 8

9 LFV with cmssm Ssaw BR ( µ 3 ) m N = (10 10,10 11,10 14 ) GV m ν1 = 10-5 V θ i = 0 SPS 1a SPS 1b SPS 2 SPS 3 SPS 4 SPS 5 Constraind Minimal Suprsymmtric Modl with Ssaw nutrino masss and lptognsis Gnral fatur: Strong dpndnc on θ 13 (S. Antusch, E. Arganda, M.J. Hrrro, A.M. Tixira, JHEP 0611 (2006) 090) θ 13 ( ) Niklaus Brgr NuFact, August 2011 Slid 9

10 LFV with Lptoquarks µ q i S S γ/z µ S Lptoquarks can lad to μ at on-loop ordr Expct nhancmnt with rgards to μ γ, whr a GIM-lik supprssion is at work Complmntary to convrsion xprimnts: accss to all quark flavours Accss to Lptoquark masss up to ~ 5 TV (K.S. Babu and J. Julio, Nucl.Phys. B841 (2010) 130) q i q j S Niklaus Brgr NuFact, August 2011 Slid 10

11 LFV in Higgs triplt modls Br MEG µ γ Mu3E Hirarchical cas Dpndnc on nutrino mass hirarchy and θ 13 µ µ convrsion (M. Kakizaki, Y. Ogura, F. Shima, Phys.Ltt. B566 (2003) 210) U 3 Niklaus Brgr NuFact, August 2011 Slid 11

12 LFV in Higgs triplt modls Br Br Dgnrat cas µ MEG µ γ µ convrsion Mu3E U Hirarchical cas MEG µ µ γ Dpndnc on nutrino mass hirarchy and θ 13 Br µ (M. Kakizaki, Y. Ogura, F. Shima, Phys.Ltt. B566 (2003) 210) Invrtd-hirarchical cas µ convrsion MEG Mu3E µ convrsion µ γ Mu3E U U 3 Niklaus Brgr NuFact, August 2011 Slid 12

13 Tr-Lvl LFV µ Modls with a Z with flavour off-diagonal couplings Modls with larg xtra dimnsions (Kaluza-Klin stats) Z Niklaus Brgr NuFact, August 2011 Slid 13

14 Prdictions: μ vs. μ γ Modl B(μ )/ B(μ γ) (prdictd) B(μ ) (xprimntal constraint) msugra with ssaw ~ 10-2 < SUSY with SO(10) GUT ~ 10-2 < SUSY + Higgs ~ 10-2 < Z, Kaluza-Klin > 1 < Littl Higgs < Higgs Triplt < µ ~ γ* ~ µ - χ ~ 0 - µ Z + - Niklaus Brgr NuFact, August 2011 Slid 14

15 A gnral ffctiv Lagrangian L μ = 2 G F ( m μ A R μ R σ μν L F μν µ ~ ~ µ - χ ~ 0 - Tnsor trms (dipol) + m μ A L μ L σ μν R F μν Four-frmion trms.g. Higgs, Z, doubly chargd Higgs... + g 1 (μ R L ) ( R L ) + g 2 (μ L R ) ( L R ) scalar + g 3 (μ R γ μ R ) ( R γ μ R ) + g 4 (μ L γ μ L ) ( L γ μ L ) γ * + g 5 (μ R γ μ R ) ( L γ μ L ) + g 6 (μ L γ μ L ) ( R γ μ R ) + H. C. ) µ vctor - +.g. suprsymmtry Z (Y. Kuno, Y. Okada, Rv.Mod.Phys. 73 (2001) 151) Niklaus Brgr NuFact, August 2011 Slid 15

16 And a simplr Lagrangian m μ κ L LFV = A R μ R σ μν L F μν + (μ L γ μ L ) ( L γ μ L ) (κ+1)λ 2 (κ+1)λ 2 Rtain only on loop trm and on contact trm Ratio κ btwn thm Common mass scal Λ Allows for snsitivity comparisons btwn μ and μ γ In cas of dominating dipol couplings (κ = 0): B(μ ) = (ssntially αm ) B(μ γ) Niklaus Brgr NuFact, August 2011 Slid 16

17 Why μ? Muons ar plntiful and clan Complmntary to μ γ and convrsion on nucli Advancs in dtctor tchnology allow for high rat & high prcision xprimnts Thr body dcay offrs mor constraints and options to study LFV mchanism and CP violation in cas of a discovry A sarch for μ with a snsitivity of has a larg potntial to discovr LFV or to st vry stringnt bounds on nw physics Niklaus Brgr NuFact, August 2011 Slid 17

18 An xprimnt sarching for μ

A μ xprimnt Nd a lot of muons Us th world s highst intnsity DC muon bam at PSI 9 Up to 10 muons pr scond Nd to control backgrounds at th 10-16 lvl Nd xcllnt vrtx and timing

19 A μ xprimnt Nd a lot of muons Us th world s highst intnsity DC muon bam at PSI 9 Up to 10 muons pr scond Nd to control backgrounds at th lvl Nd xcllnt vrtx and timing rsolution to gt rid of accidntals Nd xcllnt momntum rsolution to gt rid of μ νν dcays Thin pixl silicon trackr and scintillating fibr timing dtctor Niklaus Brgr NuFact, August 2011 Slid 19

20 Muons at PSI Th Paul Schrrr Institut (PSI) in Villign, Switzrland has th world s most powrful DC proton bam (2.2 ma at 590 MV) Pions and thn muons ar producd in rotating carbon targts Niklaus Brgr NuFact, August 2011 Slid 20

21 Muons at PSI DC muon bams at PSI: 8 μe1 bamlin: ~ 5 10 muons/s 8 πe5 bamlin: ~ 10 muons/s (MEG xprimnt) 9 μe4 bamlin: ~ 10 muons/s SINQ (spallation nutron sourc) targt could vn provid ~ muons/s Th μ xprimnt (final stag) would rquir 10 9 muons/s focusd and collimatd on a ~2 cm spot Niklaus Brgr NuFact, August 2011 Slid 21

22 Backgrounds Accidntal coincidncs of a dcay positron with an lctron-positron pair from Bhabha scattring or photon convrsion Can b supprssd by xcllnt timing and vrtx rsolution and a larg targt ara Us a hollow doubl con targt à la SINDRUM mad of aluminium Niklaus Brgr NuFact, August 2011 Slid 22

23 Main background µ ν μ W γ* ν } E miss } E tot Branching Ratio Th most svr background is th intrnal convrsion procss μ νν -5 Branching fraction Nd xcllnt momntum rsolution to rjct this background E (MV) (R. M. Djilkibav, R. V. Konoplich, Phys.Rv. D79 (2009) ) m µ Niklaus Brgr NuFact, August 2011 Slid 23 tot

17% pr layr MEG (2010) Σ /p (53 MV/c) = 0.

24 Prvious muon dcay xprimnts + γ SINDRUM (1988) Σ /p (50 MV/c) = 5.1% p Σ /p (20 MV/c) = 3.6% p Σθ (20 MV/c) = 28 mrad Vrtx: Σ 1 mm d X0 (MWPC) = % pr layr MEG (2010) Σ /p (53 MV/c) = 0.6 % p Σ (53 MV/c) = 11 mrad θ Σ (53 MV/c) = 7 mrad φ Vrtx: Σ 1.1 mm, Σ 2.0 mm r z Aim for similar angular and momntum rsolution, high rats and bttr vrtx rsolution Niklaus Brgr NuFact, August 2011 Slid 24

25 Tracking dtctor for μ 10 9 lctrons/s disfavour a gas dtctor Us silicon Fast radout Nd bst possibl momntum and vrtx rsolution Gt vrtx prcision by using a pixl snsor Momntum rsolution dominatd by multipl scattring Rduc multipl scattring by making snsor thin Niklaus Brgr NuFact, August 2011 Slid 25

26 Silicon dtctor tchnolohis Tchnology Thicknss Spd Radout ATLAS pixl 260 μm 25 ns xtra RO chip DEPFET (Bll II) 50 μm slow (frams) xtra RO chip MAPS 50 μm slow (diffusion) fully intgratd HV-MAPS > 30 μm O(100 ns) fully intgratd Niklaus Brgr NuFact, August 2011 Slid 26

27 HV-MAPS High voltag monolithic activ pixl snsors Implmnt logic dirctly in N-wll in th pixl - smart diod array Us a high voltag commrcial procss (automotiv industry) Small activ rgion, fast charg collction Can b thinnd down to < 50 μm Low powr consumption (I.Pric, P. Fischr t al., NIM A 582 (2007) 876 (ZITI Mannhim, Uni Hidlbrg)) N-wll E fild P-substrat Particl Niklaus Brgr NuFact, August 2011 Slid 27

Snsor Spcs Modul siz 6 1 cm (innr layrs) 6 2 cm (outr layrs) Pixl siz 80 80 μm Goal for thicknss: 50 μm 1 bit pr pixl, zro supprssion with tun DAC on chip 2 Powr: 150 mw/cm Data output 800 Mbit/s Tim

28 Snsor Spcs Modul siz 6 1 cm (innr layrs) 6 2 cm (outr layrs) Pixl siz μm Goal for thicknss: 50 μm 1 bit pr pixl, zro supprssion with tun DAC on chip 2 Powr: 150 mw/cm Data output 800 Mbit/s Tim stamps vry 100 ns (10 MHz clock for low powr consumption, air cooling) Prototyps succssfully tstd: AMS 350 nm procss Radiation tolrant Low nois: S/N > 40 AMS 180 nm snsors bing tstd Niklaus Brgr NuFact, August 2011 Slid 28

29 Possibl trackr layout 8 cm TM Support snsors on Kapton prints, with aluminium signal and powr lins Four layrs in two groups in a ~ 1.5 Tsla fild Total matrial fw of X, fw layrs 0 Add a scintillating fibr trackr to rduc combinatorics through timing 30 MV 15 MV 20 MV B(magnt)=1.4 Tsla 20mm 12x2 (10x60 mm2) 30mm 18x2 (10x60 mm2) 80mm 24x3 (20x60 mm2) 130mm 40x4 (20x60 mm2) Niklaus Brgr NuFact, August 2011 Slid 29

30 Timing Th silicon dtctor is rad out with 10 MHz (powr consumption) Hundrd lctron tracks in on fram Can b rsolvd by scintillating fibr trackr Rsolution ~ 100 ps - on avrag on lctron Niklaus Brgr NuFact, August 2011 Slid 30

31 Accptanc Track lctrons from with p = MV/c Accptanc dpnds on th modl Gnrally bttr for four-frmion (rd) than for photon pnguin graphs Low minimum momntum rquird L μ = 2 G F ( m μ A R μ R σ μν L F μν + m μ A L μ L σ μν R F μν + g 1 (μ R L ) ( R L ) + g 2 (μ L R ) ( L R ) + g 3 (μ R γ μ R ) ( R γ μ R ) + g 4 (μ L γ μ L ) ( L γ μ L ) + g 5 (μ R γ μ R ) ( L γ μ L ) + g 6 (μ L γ μ L ) ( R γ μ R ) + H. C. ) Niklaus Brgr NuFact, August 2011 Slid 31

32 Prformanc studis μ νν (All vry prliminary) Prformanc dpnds on background rjction Background rjction for μ νν dpnds on momntum rsolution For Σ = MV, snsitivity vn E blow possibl Simulations indicat that w can rach this with 50 μm snsors Niklaus Brgr NuFact, August 2011 Slid 32

33 Status of th projct Intrsting ida at an arly stag Work on snsors and mchanics as wll as track rconstruction at Hidlbrg Univrsity (S. Bachmann, C. Drsslr, P. Fischr, M. Kihn, R. Narayan, I. Pric, S. Rabnckr, A. Schöning, D. Widnr, B. Windlband, N. Brgr) Looking for collaborators, svral groups intrstd, mayb you too? LOI plannd for 2011 Niklaus Brgr NuFact, August 2011 Slid 33

Summary Lpton flavour violation might b just around th cornr Novl concpt for an xprimnt sarching for μ Tchnologis: HV monolithic pixl snsor and fibr trackr -16

34 Summary Lpton flavour violation might b just around th cornr Novl concpt for an xprimnt sarching for μ Tchnologis: HV monolithic pixl snsor and fibr trackr -16 Snsitivity of 10 sms fasibl First pixl trackr prototyp in 2012? Aftr mor than 20 yars, tim has com to rpat th vry succssful SINDRUM xprimnt Niklaus Brgr NuFact, August 2011 Slid 34

36 Backup Matrial

37 LFV with Lptoquarks BR(μ ) BR(μ ) < Can driv μ branching ratio from fitting nutrino masss and constraints from μ convrsion on nucli (K.S. Babu and J. Julio, Nucl.Phys. B841 (2010) 130) Snsitiv to multi-tv lptoquarks M ω 2/3 (TV) Niklaus Brgr NuFact, August 2011 Slid 37

38 LFV in Littl Higgs Modls µ µ X N i ν j Z Littl Higgs modls allow for μ µ X N i Z µ N i ф Z/Z /γ X N i X ф N j Niklaus Brgr NuFact, August 2011 Slid 38

39 LFV in Littl Higgs Modls Β(µ γ). Β(µ Ti Ti) Β(µ Ti Ti) Β(µ ē) Β(µ γ) Simplst Littl Higgs Modl Convrsion xprimnts provid strongst constraints Accss to scals > 50 TV (curvs) (F. dl Aguila, J.I. Illana, M.D. Jnkins, JHEP 1103 (2011) 080) Niklaus Brgr NuFact, August 2011 Slid 39

Search for µ eee at the High Intensity and Technology Frontier: The Mu3e Experiment

Search for µ eee at the High Intensity and Technology Frontier: The Mu3e Experiment Sarch for µ at th High Intnsity and Tchnology Frontir: Th Mu3 Exprimnt Johns-Hopkins Workshop Hidlbrg, July 21-23, 2014 André Schöning Physikalischs Institut, Univrsität Hidlbrg 1 History of LFV Dcay xprimnts