Lepton Flavor Violation Experimental Overview

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1 Lepton Flavor Violation Experimental Overview Masaharu Aoki Osaka U. APPEAL07 KEK 2007/2/19-21

2 Contents Introduction τ-decay experiments μ eγ experiment : MEG μ-e Conversion : MECO, mu2e and PRISM/Phase-1

3 Golden Trio g-2 EDM c-lfv " " mixing large top Yukawa coupling e! 0! 0 B ~ e Real Imaginary m 2 ẽẽ m 2 ẽ µ m 2 ẽ τ slepton mass matrix m 2 µẽ m 2 µ µ m 2 µ τ m 2 τẽ m 2 τ µ m 2 τ τ τ-lfv

Violation (c-lfv) Neutrino-mixing predicts very small amount of c-lfv via higher order

4 Lepton Flavor Mixing Quark Mixing : Kobayashi-Maskawa Matrix Neutrino Mixing : Maki-Nakagawa-Sakata Matrix charged Lepton Mixing : not-yet-observed charged Lepton Flavor Violation (c-lfv) Neutrino-mixing predicts very small amount of c-lfv via higher order diagram; it is as small as practically impossible to observe in foreseeable future. c-lfv = Physics beyond SM 4

Theoretical Predictions Process Current Limit SUSY-GUT level Future SUSY+Seesaw, MSW Large Angle µ N e N 10-13 10-16

5 Theoretical Predictions Process Current Limit SUSY-GUT level Future SUSY+Seesaw, MSW Large Angle µ N e N ,10-18 µ e γ τ µ γ SUSY-GUT MEG Phase-1 MEG Phase-1 PRSM/PRIME PRISM/PRIME Courtesy Hisano 5

6 Slepton Mixing Mechanism (m 2 l ) ij = m 2 0δ Plank mass scale SUSY-GUT GUT Yukawa interaction SUSY Seesaw Model Neutrino Yukawa interaction ( m 2 l ) ij 0 (m 2 L) 21 3m2 0 + A2 0 8π 2 h 2 t V td V ts ln M GUT (m 2 L) 21 3m2 0 + A2 0 M RS 8π 2 h 2 i U i1 U i2 ln M GUT M RS Quark mixing matrix Neutrino mixing matrix PRISM/Phase-1 LoI (2006)

LHC and c-lfv if LHC finds SUSY particle Physics of slepton mass matrix will be strengthened. Further exploration of SUSY structure (SUSY-GUT, SUSY-Seesaw) will become more important.

7 LHC and c-lfv if LHC finds SUSY particle Physics of slepton mass matrix will be strengthened. Further exploration of SUSY structure (SUSY-GUT, SUSY-Seesaw) will become more important. if LHC does not find SUSY particle high-intensity exp. comes forefront. ( e ; Ti) SINDRUM II LHC Phase-1 MEG ( e MECO ( e;al) PRISM ( e;ti ( e ) m (TeV)

8 τ-lfv

τ-lfv τ μγ : 3.1 10-7 (Belle), 0.68 10-7 (BaBar) τ eγ : 3.9 10-7 (Belle), 1.1 10-7 (BaBar) τ lll : 1.1~3.5 10-7 (Belle), (1~3) 10-7 (BaBar) τ lk S : (0.52~0.60) 10-7 (Belle) τ lη : (1.5~2.

9 τ-lfv τ μγ : (Belle), (BaBar) τ eγ : (Belle), (BaBar) τ lll : 1.1~ (Belle), (1~3) 10-7 (BaBar) τ lk S : (0.52~0.60) 10-7 (Belle) τ lη : (1.5~2.3) 10-7 (Belle) τ lη : (Belle) τ lπ 0 : (Belle) τ lv 0 : (2.0~7.7) 10-7 (Belle) τ lhh : (1.6~8.0) 10-7 (Belle), (0.7~4.8) 10-7 (Babar) τ pγ : (Belle), τ pπ 0 : (Belle) τ (anti-)λπ - : (0.72~1.4) 10-7 (Belle) 90%C.L.

10 B-factories Asymmetric-energy e + e - collider at Υ(4S) For B physics σ(ττ)~0.9nb, σ(bb)~1.1nb B-Factory is τ-factory >500 * -1 >4.5x10 8 τ-pairs Good particle ID ability : Br~10-8 >300 * -1 >3.0x10 8 τ-pairs 10

11 τ µγ : Belle and BaBar Belle : ±5σ box Belle : Br<3.1x10-7 / 86.3 * -1 ε = 11.1% 2D EML fit with ±5σ signal box N signal = 0, N BG = 54 N signal is constrained to be 0. BaBar : Br<0.68x10-7 / 232 * -1 ε = 9.4% 1D EML fit with ±2σ ΔE band N signal = 2.2, N BG = 143 N is allowed to be negative. BaBar : ±2σ band Background Limited τ µνν + initial-state radiation (ISR) 11

12 Future prospects Super B-factory 2010 ~ >10 times more data τ lγ Background limited τ lη Higgs-mediated SUSY-seesaw τ lll τ lk s R-parity violating SUSY 12

13 Future prospect (2) Possible sensitivity with Super B-factory Red band for 5~10 ab -1 Super B-factory 13

14 μ-lfv μ eγ μn en

15 μ eγ signal μ + e + γ background e + μ + θ eγ = 180 E e = E γ = 52.8 MeV T e = T γ γ e + μ e γ ν ν ν ν μ + γ e + accidental μ e ν ν μ e γ ν ν ee γ γ ez ez γ μ + ν ν μ + γ

16 PSI ICEPP, KEK, Waseda U., INFN, PSI, Budker Inst. PSI-πE5 Beam Line R μ : x 10 8 /s Run: Running Time: 4 x 10 7 s S.E.S.: 4 x 10-14

BR acc = R µ E e E 2 γ θ 2 eγ t eγ Exp./Lab Year ΔEe/Ee (%) ΔEγ /Eγ (%) Δteγ (ns) Δθeγ (mrad) Stop rate (s-1) Duty cyc. (%) BR (90% CL) SIN 1977 8.7 9.3 1.4-5 x 10 5 100 3.6 x 10-9 TRIUMF 1977 10 8.

17 BR acc = R µ E e E 2 γ θ 2 eγ t eγ Exp./Lab Year ΔEe/Ee (%) ΔEγ /Eγ (%) Δteγ (ns) Δθeγ (mrad) Stop rate (s-1) Duty cyc. (%) BR (90% CL) SIN x x 10-9 TRIUMF x x 10-9 LANL x x Crystal Box x 10 5 (6..9) 4.9 x MEGA x 10 8 (6..7) 1.2 x MEG x x Liquid Xenon calorimeter (scintillation)

18 MEG Schedule Physics Run Start 2007~2009 : Production Run continues μ + /s 2-years : BR~ ~ Detector upgrades BR~10-14 μ eee?

19 μ-e Conversion Muonic Atom (1S state) μ-e Conversion µ Lepton Flavor is violated: LFV Forbiden in Standard Model Physics of chared Lepton Flavor Mixing 19

Physics of μ-e Conversion SUSY-GUT, SUSY-seesaw (Gauge Mediated process) BR = 10-15 = BR(μ eγ) O(α) τ lγ SUSY-seesaw (Higgs Mediated process) BR = 10-12 ~10-15 τ lη Doubly Charged Higgs Boson

20 Physics of μ-e Conversion SUSY-GUT, SUSY-seesaw (Gauge Mediated process) BR = = BR(μ eγ) O(α) τ lγ SUSY-seesaw (Higgs Mediated process) BR = ~10-15 τ lη Doubly Charged Higgs Boson Logarithmic enhancement in a loop diagram for μ - N e - N, not for μ e γ M. Raidal and A. Santamaria, PLB 421 (1998) 250 N N SUSY with R-parity Violation Leptquarks Heavy Z Compositeness Multi-Higgs Models

(MDO) ΔE e =350 kev (BR:10-16 ) Beam Pion Capture π - +(A,Z) (A,Z-1)* γ+(a,z-1) γ e + e - Prompt

21 Principal of Experiment Signal : μ - +(A,Z) e - +(A,Z) A single mono-energetic electron 100 MeV Delayed ~1μS PSI SINDRUM II No accidental backgrounds Physics backgrounds Muon Decay in Orbit (MDO) ΔE e =350 kev (BR:10-16 ) Beam Pion Capture π - +(A,Z) (A,Z-1)* γ+(a,z-1) γ e + e - Prompt timing High Quality μ beam for experiment High intensity Pulsed or/and High-Purity 21 BR <

22 μ-e Conversion vs. μ e γ μ - N e - N photonic non-photonic μ e γ only photonic B(μ e γ) = 200 B(μ - N e - N) Physics is complemental No Accidental Background Pulsed and/or Pure Muon Beam State-of-the-art Beamline High intensity surface muon Accidental Background State-of-the-art Detector Differenct Background Mechanism Different Technologies Experiments are also complemental

23 MECO BNL/AGS Straw Tracker Superconducting Detector Solenoid (2.0 T 1.0 T) Superconducting Transport Solenoid (2.5 T 2.1 T) Muon Beam Stop Crystal Calorimeter Muon Stopping Target µ Collimators µ Superconducting Production Solenoid (5.0 T 2.5 T) 23

24 MECO BNL/AGS Straw Tracker Superconducting Detector Solenoid (2.0 T 1.0 T) Superconducting Transport Solenoid (2.5 T 2.1 T) Muon Beam Stop Cancelled Crystal Calorimeter Muon Stopping Target µ Collimators µ Superconducting Production Solenoid (5.0 T 2.5 T) 23

25 PRISM Phase-Rotated Intense Slow Muon source High Intensity μ ± /sec High Brightness ±0.5 ~ 1.0 MeV MDO suppression High Purity π/μ ~ π b.g. suppression Pulsed 100 Hz BR(μ - +Ti e - +Ti)<

26 Staging Strategy On the evening before the MECO cancellation!""#!""$!""%!""&!"'"!"''!"'!!"'(!"')!"'*!"'#!"'$!"'% +,-. -/ / :;161 -/ /0 740 PRISM Phase Rotated Intense Slow Moun source PRIME PRISM Muon to Electron conversion experiment 5 m MECO:BR<10-16 PRISM:BR<

Staging Strategy On the evening before the MECO cancellation!""#!""$!""%!""&!"'"!"''!"'!!"'(!"')!"'*!"'#!"'$!"'% +,-. -/01234526/0 740 809:;161 <7=>+?

27 Staging Strategy On the evening before the MECO cancellation!""#!""$!""%!""&!"'"!"''!"'!!"'(!"')!"'*!"'#!"'$!"'% +,-. -/ / :;161 -/ /0 740 PRISM Phase Rotated Intense Slow Moun source PRIME PRISM Muon to Electron conversion experiment 5 m MECO:BR<10-16 PRISM:BR<

After the MECO Cancellation mu2e(fnal + xmeco) Revive of MECO After the shutdown of Tevatron Parasite on SNuMI-2 2012 ~ Renovate a Debuncher ring for beam bunching A-D Line AP4 Line AP5 Line 22

28 After the MECO Cancellation mu2e(fnal + xmeco) Revive of MECO After the shutdown of Tevatron Parasite on SNuMI ~ Renovate a Debuncher ring for beam bunching A-D Line AP4 Line AP5 Line 22 batches = s MI cycle NEUTRINO PROGRAM MUONS Booster Batches p/batch Accumulator (NuMI +Muons) Recycler p/sec (NuMI) Debuncher (Muons) p/1467ms = p/sec (Alternative: 24 batches=1.6s MI cycle p/s) 0.1s 1.367s

29 Staging of PRISM ~10 years!""#!""$!""%!""&!"'"!"''!"'!!"'(!"')!"'*!"'#!"'$!"'% +,-./0' :7; <6-=>.;. 3/B/=5CD/ :7; Production Target PRISM Phase Rotated Intense Slow Moun source PRIME PRISM Muon to Electron conversion experiment Stopping Target 5 m Phase-1:BR<10-16 Full PRISM:BR<10-18

Why Staging, why 10-18 Staging Early Realization, Discovery Understand the phenomena in a real-world step by

30 Why Staging, why Staging Early Realization, Discovery Understand the phenomena in a real-world step by step; we may Phase-1 PRISM see something new in every step of factor 10 improvements L. Calibbi, A. Faccia, A. Masiero and S.K. Vempati PRD 74(2006) Why 10-18, why full-prism Covering almost entire parameter space Study of interaction types τ μ - Al = 880 ns, τ μ - Pb = 82 ns R. Kitano, M. Koike, Y. Okada PRD 66(2002)

Phase-1 Overview Production Target Large μ yields J-PARC/MR only 60 kw out of 450kW π-capture SC-solenoid 10 11 μ/s (PSI:10 8 μ/s)

31 Phase-1 Overview Production Target Large μ yields J-PARC/MR only 60 kw out of 450kW π-capture SC-solenoid μ/s (PSI:10 8 μ/s) Stopping Target Pulsed Proton Beam π-b.g. suppression PRIME detector Curved SC-solenoid Upgradability to PRISM add Phase-Rotator-Ring

32 MECO,mu2e and Phase-1 MECO mu2e Phase-1 Machine BNL/AGS FNAL/Debuncher J-PARC/MR Energy 7.5 GeV/c 8 GeV/c 8 GeV/c Pulse 1.4 μs 1.7 μs 1.1 μs Extraction Bunched Slow Target Tungsten Graphite Muon Beamline Curved Solenoid Curved Solenoid + Vertical Field μ stop muons/s muons/s Detector Straight Curved Rate 500 khz/wire 300 DIO tracks/s Sensitivity Upgradability NO PRISM(10-18 )

33 Bunching Scheme J-PARC Accelerator Complex RCS : 1 bunch operation h=1 or h=2 w/ empty bucket MR : Empty bucket Scheme h=9 or h=8 Adiabatic dumping : small 30 GeV 8 GeV Reduce RCS painting area Smaller 3-50BT collimator 8 GeV, 7 μa ; 56 kw to NP-Hall MECO-like Scheme

Detector Rate < 1 khz Good acceptance for signal e s 30~40% B(μ - + Al e - + Al) = 4 10-17 < 10-16 (90% C.L.

34 PRIME Spectrometer Curved solenoid Cut the low momentum charged particle backgrounds; Drift-in-Torus Rejection : 10-7 ~ 10-8 Cut the neutral particle backgrounds. Detector Rate < 1 khz Good acceptance for signal e s 30~40% B(μ - + Al e - + Al) = < (90% C.L.) Collimator Detector solenoid 30MeV/c 60MeV/c 105MeV/c Curved solenoid spectrometer Traget solenoid Acceptance Transmission efficiency Top view Side view Momentum (MeV/c)

Summary The physics underneath c-lfv is very interesting, even after LHC. μ-e conversion has the best prospects for the future of c-lfv experiments.

35 Summary The physics underneath c-lfv is very interesting, even after LHC. μ-e conversion has the best prospects for the future of c-lfv experiments. The first stage towards BR=10-16 was proposed; the details will be given by next speaker, M. Yoshida and A. Sato. Full-PRISM aiming BR=10-18 is currently under development; the details will be given by the 2nd next speaker, Y. Arimoto.

J-PARC μ-e --- PRISM/Phase-1 ---

J-PARC μ-e --- PRISM/Phase-1 --- Masaharu Aoki Osaka U. ICEPP, 2007/11/06 Lepton Flavor Violation μ-lfv (SIMDRUM II) μ-e MECO, mu2e and PRISM/Phase-1 PRISM/Phase-1 @ J-PARC Lepton Flavor Mixing Quark Mixing