muon g-2/EDM experiment at J-PARC
Y. SatoKEK IPNS
On behalf of the E34 collaboration
5th Jan. 2017

2

Exp.

Th.

Muon g-2 Anomaly

0.54 ppm• >3σ deviation between muon g-2 measurement by BNL E821 and SM prediction forover 10 years.
• Theoretical prediction is being improved by continuous efforts.
 Need more precise/independent measurement.
• Muon EDM is also important– Upper limit : 𝑑 < 1.8 × 10−19 𝑒 ∙ cm(95% C. L. ) by BNL E821

3

Principle of muon g-2 Measurement
1.

Inject polarized muons to the storage ring.
– 𝜋 + → 𝜇 + 𝜈𝜇 decay

2.

Muon spin precession relative to momentum in cyclotron is proportional to g-2
under “special” condition.

𝝎 = 𝜔spin − 𝜔cyclotron =Polarized 𝜇

𝒈−𝟐 𝑒𝑩
𝑒𝑩
= 𝒂𝝁
𝟐
𝑚𝜇 𝑐
𝑚𝜇 𝑐

3.

Momentum

Detect high energy 𝑒 + from 𝜇+ decay@J-PARC MC

Storage ring#positronsSpin𝑒 + direction is correlated
to muon spin direction.
Spin
𝑒+

𝝁+

B

Time [µs] Precise measurement of 𝑔 − 2 needs precise determinations of 𝝎 and 𝑩.
– Muon-to-proton magnetic moment ratio is also used instead of 𝑒/𝑚𝜇 .

𝜈𝜇
𝜈𝑒

4

Principle of muon EDM Measurement• Non-zero EDM contributes to spin precession.
– 𝜔EDM = −

𝑒 𝜼
𝑚𝜇 2

𝛽×𝐵

(Side view)
𝐵
Muon orbit plane
𝛽

spin

up

down

• EDM can be measured from up-down asymmetry.
– 𝒜𝑈𝐷 =

𝑁up −𝑁down
𝑁up +𝑁down@J-PARC MC

Up-down asymmetry

𝛽×𝐵d(input) = 1×10-17 e・cm

Time [µs]Experimental Approaches for g-2 and EDM
𝝎𝒈−𝟐

5

𝝎𝐄𝐃𝐌

𝑒
1
𝛽×𝐸 𝜂
𝐸
𝜔=−
𝑎 𝐵 − 𝑎𝜇 − 2
+
𝛽×𝐵+
𝑚𝜇 𝜇
𝛾 −1
𝑐
2
𝑐

1. Magic momentum
𝛾 = 29.3 (𝑃 = 3.09 GeV/c)
BNL E821 (current best meas.)& FNAL E989 (upgrade)
𝑒
𝜂
𝐸
𝜔=−
𝑎 𝐵+
𝛽×𝐵+
𝑚𝜇 𝜇
2
𝑐
 FNAL E989 will start from 2017.

2. Zero 𝑬-field𝐸 = 0 at any 𝛾
J-PARC E34 (new methods)
𝜔=−

𝑒
𝑚𝜇

𝑎𝜇 𝐵 +

𝜂
2

𝛽×𝐵• Completely different techniques Different systematic uncertainty.
• More simplified equation (𝜔𝑔−2 ⊥ 𝜔EDM ) Clear separation of 𝜔𝑔−2 and 𝜔EDM .

6

Low Emittance Beam
Methods to storage muon beam
• BNL & FNAL (magic momentum approach)– Electric quadrupole field focusing
Electric focusing• J-PARC (zero E-field approach)– Low-emittance “cold” muon beam.

–

𝜎 𝑝𝑇
𝑝𝑇

< 10−5  10 cm spread over 10 km travel.

 Low emittance beam can avoid major syst. error at BNL.

Syst. Err. @BNL
Sourcesppm

Gain changes

0.12

Pile up

0.08

Lost muons

0.09

CBO

0.07

E and pitch

0.05

Total for 𝜔

0.18

7

Off-magic momentum• Off magic momentum at 300 MeV/c– Compact storage ring provides precise control of B-field.

Syst. Err. @BNL
Sourcesppm

Total for 𝜔

0.18– Spin manipulation of μ beam cancel various systematics. Total for 𝐵

0.17• 3 T, ~1 ppm local precision.

BNL & FNAL (P = 3 GeV/c, 1.45T)

J-PARC (P = 300 MeV/c, 3T)

8J-PARC E34 Experiment• New muon g-2/EDM experiment at J-PARC MLF with a newly developed method,off-magic momentum with ultra-cold muon beam.
J-PARC proton beam (3 GeV)BNL
Our goal
g-2 :0.54 ppm
 0.1 ppm
EDM : 𝟏. 𝟖 × 𝟏𝟎−𝟏𝟗 𝒆 ∙ 𝐜𝐦  𝟏𝟎−𝟐𝟏 𝒆 ∙ 𝐜𝐦

Surface 𝝁 beam Ultra-cold 𝝁 source••

Mu production
Laser ionization

 Low emittance beam
 Spin reversal

Acceleration
Injection & storage& detection
 Advanced injection & storage methods
 Good uniformity of B field by compact storage ring
 Large acceptance by tracker

66 cm diameter

J-PARC Facility (KEK/JAEA)

9

Neutrino Beam to Kamioka

Main Ring(30 GeV)

Hadron Hall
Bird’s eye photo in January of 2008

New Muon Beam Line ~H-Line~• MLF Facility
J-PARC
MLFin
building
proton beam
(3 GeV )@Muon production target

Three muon experiments• g-2/EDM• MuSEUM (Mu-HFS)• DeeMe (muon cLFV)@Transportation line

10

11

Ultra-Cold Muon Source• Low emittance muon beam is necessary
to storage muon without E-focusing.
1.

Muonium (𝝁+ 𝒆− atom) production2.

Laser ionization

unbound2P

by Laser ablated Silica Aerogel

1S

Surface muons

Ultra-cold μfrom 𝜋 + → 𝜇 + 𝜈𝜇

Acceleration

Thermalemissionp = 28 MeV/c

3 keV/c

300 MeV/c

 Low emittance muon beam with Δpt/p ~ 3keV/300 MeV ~ 10-5

12Muonium Production Target
Events/3×108 muons• Mu prod. target : Laser ablated Silica Aerogel
Drilled Aerogel
Flat Aerogel×~10

 Succeeded to enhance the Mu production rate.
• The width, pitch, and depth of the holes can be controlled.
Different hole sizewith 500 μm pitch
3.5 mm

3D view(z-stack imaging)

500 μmS. Kamal@PTEP 2014 (2014) 091C01

 Beam test for Mu production is planned in this month at J-PARC.

Time (μs)

13Muon Acceleration• Ultra-cold muon beam is transported to linac (linear accelerator) with initialacceleration and must be reaccelerated to 300 MeV/c by linac– in a sufficiently short period to avoid decay loss
– without substantial emittance growth.
• Different design to realize fast re-acceleration through wide β region.
InitialAcc.

𝝁→5.6 keVβ = 0.01

0.3 MeVβ = 0.08

RFQ

4.5 MeVβ = 0.3

IH-DTL40 MeVβ = 0.7

DAW(P = 300 MeV/c)
212MeVβ = 0.9

Disk-loaded Basic reference design for linac has been completed.
– Recently IH-DTL paper has been published @M. Otani et al., PRAB19, 040101, 2016.

14

Demonstration of Deceleration and Initial Acc.
@ J-PARC MLF test muon beamline(Feb. 2016)

Surface μ beamAcc. to E = 5.4 keV

μ (~4 MeV)

Decelerated
by thin Al foil

Deceleration and initialacceleration.

transport#event#eventTime of Flight
Data
300

450
400
350
300

Muon

250
200
150
100

#event50
0450#eventMCP
detector

400
350
300

Simulation
300

Proton250
200

 Succeed to deceleration & initial acceleration.
• Next step is muon acceleration with RFQ

150
100
50
0

0

0

0.5

1

1

1.5

2

2

2.5

3

3

3.5

4
TOF[m s]μs

Storage Magnet• Super Precision Storage Magnet– 3T with local uniformity of 1 ppm by iron shimming.

Muon storage orbit
Silicon tracking detector
2.9 m

66 cm

15

16

B-Field Shimming
Before shimming

600 ppm-1000 ppm

After shimming

0.6 ppmr = 140 mm-0.8 ppm• ppm level uniformity is achieved.
 Shimming method is established.

100 ppm[PRD73 072003 (2006)]

17

Muon Injection Scheme @J-PARC• Injection method used at BNL (Horizontal injection + kicker) can not be applied toour experiment due to compact storage ring and strong B field.
• 3D-spiral injection scheme has been designed. H. Iinum et al. NIMA 832 (2016) 51– Smooth connection btw injection and storage regions w/o any sources of error field.
– Vertical motion is controlled by radial field (Br).
• Pulsed magnetic kicker to guide muon beam into stable orbit.
• Weak-focusing magnetic field to hold muon beam in stable orbit.

3D spiral injection + kicker

Upper plate (pure iron)channelPole tip

Return yoke (pure iron,
cylindrical shape)

BR




F

BR

 beamInjection
regionStorage region（weak focus）

Main
Main coilsolenoid¼ modelcoil Higher injection efficiency : ~80% ⇔ 3-5% @BNL E821 [PRD73 072003 (2006)]

Demonstration of Spiral Injection• Demonstration of spiral injection is ongoing.

Electron gun(112 keV/c)

Mini-solenoid(102 G)

Iinuma, Nakayama, Osawa, Rehman Succeeded in observation of first spiral track.

18

19

Positron Tracking Detector• Compact storage ring gives good uniformity of B-field,
but lead to dense muon decay.
Silicon strip tracking detector (not calorimeter)• High position resolution and tracking efficiency• High hit rate capability and early-to-late stability

3T

𝝁+
66 cm

– 40k muons/spill with 25 Hz @final goal
– Rate changes by a factor of ~1/150 during 5 times dilated lifetime.

• No contamination of electromagnetic field in the muon storage region.
– ΔB/B < 1 ppm and E-field << 10 mV/cm

Flex
Readout ASIC
Strip sensor
Front-end board
Support frame
Heat pipe• Detector construction fund is partially covered by Kiban-S.
 Move to detector construction phase.

(Strip direction)

20

Silicon Strip Sensor and Front-end ASIC
SliT128 (128ch/chip)

190 μm pitch

Full-size sensor production• Basic properties of sensors have been confirmed.
 Mass production will start in this JFY.

FPGA

Sensor

Front-end ASIC “SliT128A” (3rd prototype)• Confirmed to satisfy almost all requirements for ASIC.
 Final version of ASIC will be fabricated in next JFY.
Full-size sensor & 3rd prototype ASIC

Pitch adaptor@Sr-90• Signal from radiation source is observed as expected.
• Application for muonimun HFS experiment “MuSEUM” at J-PARC.

21

Status of J-PARC E34 Collaboration• 144 members from 9 countries, 49 institutions (Still evolving).
• Submitted technical design report (TDR).
– Aim 0.4 ppm as stage 1.
BNL E821g-2

0.46 ppm

EDM

0.9×10-19 e・cm

J-PARC E34
0.37 ppm( 0.1 ppm)
1.3×10-21 e・cm

• Approved as one of priority projects
in the future by KEK.
• Focused review to move construction stage
was held (Nov.15-16, 2016)

CM12@J-PARC 2016.6

Review of theg-2 experiment (E34)
November 15-16, 2016
Steve Kettell, Chairperson
Accelerator* Haruo Miyadera, Toshiba
Mary Convery, FNAL
Subrata Nath, LANL
Deborah Harris, FNAL
Junji Haba, KEK

Muon beam and source* Klaus Jungmann, KVI
Hiroaki Miyatake, KEK
Makoto Fujiwara, TRIUMF
Thomas Browder, Hawaii
Steve Kettell, BNL
Storage and detector* David Hertzog, University of Washington
Gerco Onderwater, Groningen
Ivan Logashenko, Novosibirsk
Akira Yamamoto, KEK
Ryuichiro Kitano, KEK
Kazunori Hanagaki, KEK/Osaka
LEGEND

Laboratory Management
Takashi Kobayashi, KEK
Takeshi Komatsubara, KEK
Katsuo Tokushuku, KEK* Writing lead

Focused Review @J-PARC 2016.11

Summary• J-PARC E34 experiment measures muon g-2 and EDM by completely different
approach : “off-magic momentum with ultra-cold muon beam”.
• A lot of interesting techniques are being developed.
– No focusing E-field to storage muon beam
• Low emittance muon beam
– Efficient muonium production and laser ionization & muon re-acceleration– 3D-spiral injection scheme– Compact storage ring
• Good uniformity of B-field & large acceptance by tracking detector.

• TDR was submitted.
– g-2 : 0.37 ppm (final goal is 0.1 ppm)
– EDM : 1.3×10-21 e・cm
 Statistical precision exceeds BNL E821.
• Moving to construction phase.
– Partial construction fund (detector) is approved.
• Job opening for the H-Line construction@hecforum:06663– http://www.kek.jp/en/Jobs/

22

23

BackupDipole Moments

24• Electromagnetic interaction Hamiltonian with magnetic and electric fields

𝓗 = −𝝁 ∙ 𝑩 − 𝒅 ∙ 𝑬
Magnetic dipole moment (MDM)• 𝜇 = 𝒈𝜇0 𝑠 = 2 𝒂 + 1 𝜇0 𝑠
Anomalous magnetic moment• 𝑎 = 𝑔 − 2 /2

• Induced by any interaction.
NPSMe.g. SUSY

QED

EW
𝜇

𝛾

Had.

𝑍

𝜇

𝜒0

lbl
HadronHadron Precise test of the SM(𝜇0 = 𝑞/2𝑚)

Electric dipole moment (EDM)• 𝑑 = 𝜼𝜇0 𝑠• Induced by T&P-violating interaction.
Time reversal
+++

+++

---

---

• Highly suppressed in the SM– 𝑑 SM ~10−38 𝑒 ∙ cm
– Out of experimental reach.
 Non-zero EDM is evidence for NP

Ultra-cold Muon Beam at H-line• Design of H-line and the muon acceleration test.

4

25

RFQ Commissioning@ J-PARC LINAC facility, Jun. 2015.
• Nominal power (4.6 kW) and duty operation.
• No RF-related background with MCP.

RFQ

MCP

 RFQ is ready.
• Muon acceleration with RFQ is planned.

26

27

Technically driven scheduledesignCalendar Year
Japanese Fiscal YearMonth
Area Task Item

prototype

CY2014
JFY2014F3

F4evaluation

CY2015
JFY2015F1F2F3

Installation

fabrication

CY2016
JFY2016
F4

F1

F2

F3

construction

comissioning

CY2017
JFY2017
F4

F1

F2

F3

physics run

CY2018
JFY2018
F4

F1

F2

F3

CY2019
JFY2019
F4

F1

F2

F3

CY2020
JFY2020
F4

F1

F2

F3

CY2021
JFY2021F4H-lineMuon Source
Laser
Accelerator

High Precision Magnet
Kicker System
Beam Transport
Detector
Data taking

Assumption : Major construction fund become available in JFY2016

F1

F2

F3

F4

Comparison of Experiments

28

Efficiency

29

Laser Timing

30

31

Fake EDM Signal by Misalignment• EDM is measured from up-down asymmetry “AUD”.
Simulation with 1 mrad misalignment and null EDM signal

No oscillation

Oscillate withdifferent phase

AUD

No oscillation

 The alignment must be controlled with 10 μrad accuracy
to measure EDM with 10−21 𝑒 ∙ cm.

Fake EDM

32

Alignment Monitor
Interferometer by optical frequency comb with a ball-lens target•

Absolute length can be measured with μm level up to 10 m.
–

W. Sudatham, H. Matsumoto, S. Takahashi, K. Takamasu Precis Eng 43, 486 (2016)

Interferometer signal by opticalfrequency comb is observed.

••

Ball-lens

Try to measure absolute length by ourselves and apply it in our detector system.
“Ball-lens” will be located on the detector as a target to measure the position of detector.
– Incoming beam with any direction will focus at the ball-lens end surface.
– The reflected beam retraces its incoming path in the opposite direction.

FNAL@ICHEP2016

33

FNAL@ICHEP2016

34

FNAL@ICHEP2016

35

FNAL@ICHEP2016

36

FNAL@TAU201637