Muon g-2/EDM experimentat J-PARCSchwingerFest, UCLA
Dec 4, 2018Tsutomu Mibe (KEK)
for the J-PARC g-2/EDM collaboration
1
www.g-2.kek.jp
28 Julian Schwinger
Fig. 3.1 Memorial lecture of Professor Julian Schwinger for Professor Sin-itiro Tomonaga (July8, 1980, Tokyo)
Two shakers of physics
2
Memorial lecture of Professor Julian Schwinger for Professor Sin-itiro Tomonaga (July 8, 1980, Tokyo)
“Shin (�) : to wave, shakeSchwing : to swing, shake”
Lecture note on physics 746, pp 27, 2008
Why new g-2 experiment?
• An important discovery must be confirmed by independent experiments.– a(SM) : e+e- expt’s, theory groups, lattice groups– a(exp) : BNL à Fermilab, J-PARC
• New experimental method to explore further precision.
3
Three steps of g-2 measurement
1. Prepare a polarized muon beam.
2. Store in a magnetic field (muon’s spin precesses)
3. Measure decay positron
4
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ù
êêë
é÷÷ø
öççè
æ+´+
´÷÷ø
öççè
æ-
---=cEB
cEaBa
me
!!!
!!!!
bhbg
w µµ 2112
π+ μ+νμ
spin 0
neutrino� left handed
helicity�−� helicity�−�
μ+
e+
spin
μ+
B
spin
Ideal g-2 experiment?
• Beamline phase space matched at injection • All muons have same lifetime• All muons have same spin direction• No muon losses
5
μ+
B
Y. Semertzidis, g-2 school at BINP (2018)
https://indico.inp.nsk.su/event/14/
6
Thermal muoniumproduction,Ionization laser
Muon storagemagnet(3 T)
MLF muon experimentalfacility (H-line)
Positron trackingdetector
Proton beam (3 GeV)
Surface muon (4 MeV)
Ultra-slow muon (25 meV)
Reaccelerated muon(212 MeV)
3D spiral injectionMuon LINAC
Muon g-2/EDMexperimentat J-PARC
Features:• Low emittance muon beam (1/1000)• No strong focusing (1/1000) & good injection eff. (x10)• Compact storage ring (1/20) • Tracking detector with large acceptance• Completely different from BNL/FNAL method
7
The Collaboration 102 members (Canada , China, Czech,France, Japan, Korea, Russia, USA)
New Ph.Ds
8
Awards
9
PASJ poster award
LINAC 2018 poster award
KEK student day poster award
muon g-2 and EDM measurements
10
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---=cEB
cEaBa
me
!!!
!!!!
bhbg
w µµ 2112
( )úûù
êëé ´+-= BBa
me !!!!
bhw µ 2
In uniform magnetic field, muon spin rotates ahead of momentum due to g-2 = 0
ω = −
em
aµB+η
2
β ×B+Ec
#
$%
&
'(
)
*+
,
-.
BNL E821 approachγ=30 (P=3 GeV/c)
J-PARC approachE = 0 at any γ
J-PARC E34
general form of spin precession vector:
FNAL E989
Conventional muon beam(BNL, Fermilab)
proton π+ μ+
pionproduction
decay
emittance~1000π mm�mrad
Strong focusingMuon lossBG π contamination
11
Muon beam at J-PARC
Reacceleratedthermal muon
proton π+ μ+
pionproduction
decay
cooling μ+
emittance~1000π mm�mrad
emittance1π mm�mrad
Strong focusingMuon lossBG π contamination
Free from any of these
12
( + - ) + + -( ) 2 5
2 5 7( 5( 5 7)
.A
HA A
0 1 C(
2E A E7 . 7 C 4 103,-
+ -2 5
( 2 5 7) )
µ
µ µ
/
Re-accelerated thermal muon
Experimental sequence
14
40ms (25 Hz)
~1μs
40 μs
Surfacemuon beam(28 MeV/c)
Thermalmuonium(3keV/c)
Ultra-slow muon(3keV/c)
Acceleration + injection(300 MeV/c)
Storage and detection(300 MeV/c)
~1ns
~3ns
laser ionization
μ+àe+
μ+
μ+
Mu
μ+
s]µ) [aTime (modulo T0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
Up-
dow
n as
ymm
etry
0.06-
0.04-
0.02-
0
0.02
0.04
0.063-10´
1110´ = 5.7+e = 50% N+µP < 275 MeV+e200 MeV < Ecm× e-2010´ = 1 µd
s]µTime [0 5 10 15 20 25 30
cou
nts
/ 5 n
s+
Dec
ay e
710
810
9101110´ = 5.7+e = 50% N+µP
< 275 MeV+e200 MeV < E
15
Expected time spectrum of e+ in µàe+nn decay
w
ω = −
em
aµB+η
2
β ×B( )#
$%&
'(
e+ decay time (µsec)
∝ EDM
Mod(e+ decay time, Tg-2) (µsec)
Expected uncertainties
16
Table 5 Summary of statistics and uncertainties
Estimation
Total number of muons in the storage magnet 5.2× 1012
Total number of positrons 0.57× 1012
Effective analyzing power 0.42
Statistical uncertainty on ωa [ppb] 450
Statistical uncertainty on ωp [ppb] 100
Uuncertainties on aµ [ppb] 460 (stat.)
< 70 (syst.)
Uncertainties on EDM [10−21 e·cm] 1.4 (stat.)
0.36 (syst.)
Once the ωa and ωp are extracted from the experimental data, aµ is obtained from Eq. 5.435
Table 5 summarizes statistics and uncertainties for 2× 107 seconds of data taking. The436
estimated statistical uncertainties on ωa and ωp are 450 ppb and 100 ppb, respectively.437
Thus, the statistical uncertainty of aµ would be 460 ppb.438
Systematic uncertainties on ωa are estimated as follows. A timing shift due to pile up of439
hits in the tracking detector is estimated as less than 36 ppb in the detector simulation by440
taking into account time responses of readout electronics. A correction for pitch angle is not441
necessary in the case of the muon storage in the perfect weak magnetic focusing field [53]. A442
difference in the actual field distribution from the perfect case leads to a systematic uncer-443
tainty of 13 ppb which is estimated from a precision spin-tracking simulation of the muon444
beam storage. Residual electric field modifies ωa through the β × E term. With 1 mV/cm445
monitoring resolution for an E-field, the error on ωa is 10 ppb. Other effects, such as delayed446
high-energy positrons and differential decay, are of the order 1 ppb. In the ωp measurement,447
absolute calibration of the standard probe has an uncertainty of 25 ppb. Positioning res-448
olution of the field mapping probe at the calibration point and the muon storage region449
leads to 20 ppb and 45 ppb uncertainties, respectively. Other effects, such as field decay and450
eddy current from kicker are less than 10 ppb. In summary, we estimate that the combined451
systematic uncertainties on aµ is less than 70 ppb.452
A muon EDM will produce muon spin precession out of the horizontal plane that is defined453
by the ideal muon orbit. This can be seen from Eq. 4 where the second term is the EDM454
term that is perpendicular to the aµ term. Due to the fact that the EDM term generates455
vertical motion of the spin, one can extract the EDM term from the oscillation of the up456
and down asymmetry AUD(t) in number of positrons detected,457
AUD(t) =Nup(t)−Ndown(t)
Nup(t) +Ndown(t)=
PAEDM sin (ωtott+ φ)
1 + PA cos (ωtott+ φ), (8)
where P and A are the polarization of the muon and an effective analyzing power of muon458
decay, respectively. AEDM is an effective analyzing power associated with the EDM. A459
simulated up-down asymmetry in the case of dµ = 1× 10−20 e · cm is shown in Fig. 14 (right).460
The estimated statistical sensitivity for EDM is 1.5× 10−21 e · cm (See Table 5).461
19/21
Bird’s eye photo in Feb. 2008 17
Proposed experimental site
18
Parking lot
muonproductiontarget
sparation neutronsource
g-2/EDMstorage magnet
muon linac
H-Line
MuSEUMDeeMe
Material and Life science Facility in J-PARC
New ElectricPower substation
H-line being constructed!
19
Photo by T. Yamazaki
To g-2/EDM
New power station being constructed
20Photo by T. Yamazaki
21
Production target
(20 mm)
3 GeV proton beam
( 333 uA)
Surface muon beam
(28 MeV/c)Muonium Production
(300 K ~ 25 meV⇒2.3 keV/c)
SiliconTracker
66 cm
Super Precision Storage Magnet
(3T, ~1ppm local precision)
Resonant Laser Ionization of Muonium (~106 µ+/s)
Δ(g-2) = 0.1 ppm
ΔEDM = 10-21 e�cm
22
muon beam
Muonium(µ+e-)
Silica aerogel�SiO2, 30 mg/cc�
Laser-ablated holes
8 mm
� no hole� w/ holes
P. Bakule et al., PTEP 103C0 (2013)G. Beer et al., PTEP 091C01 (2014)
Muon LINAC
30
406172.
b
-
5
0
0
0
0
5 5 58 8
-
23
x (mm)8− 6− 4− 2− 0 2 4 6 8
x’ (m
rad)
8−6−4−2−02468
y (mm)8− 6− 4− 2− 0 2 4 6 8
y’ (m
rad)
1.5−
1−
0.5−
0
0.5
1
1.5
(deg.)φ ∆10− 8− 6− 4− 2− 0 2 4 6 8 10
w (M
eV)
∆
1−0.8−0.6−0.4−0.2−
00.20.40.60.8
1
p (MeV/c)298 300 302
Even
ts
01000200030004000500060007000
RMS/Mean: 0.04%Mean: 299.7 MeV/c
Phase space distributions after muon LINAC (simulation)
Muon RF acceleration for the first time!
24
J-PARC MLF D2 area, October 2017 Slide by M. Otani
Muon RF acceleration for the first time!
25
J-PARC MLF D2 area, October 2017 Slide by M. Otani
S. Bae et al.,Phys. Rev. AB 21, 050101 (2018).
26
An accelerating structure (IH-DTL cavity)to 1.3 MeV Mar 2017, Photo by M. Otani
Design: M. Otani et al., Phys. Rev. AB 19, 040101 (2016)
Muon beam injection and storage
Horizontal injection + kicker
(BNL E821, FNAL E989)
3D spiral injection + kicker
(J-PARC E34)
Injection efficiency : 3-5%(*)
(*) PRD73,072003 (2006)
Injection efficiency : ~85%
H. Iinuma et al., Nucl. Instr. And Methods. A 832, 51 (2016)27
Muon storage magnet and detector
28
Cryogenics
e+ trackingdetector
2900 mm
Muon storage orbit
Iron yoke
Super conducting coils
666 mm
Drawn by Hitachi Co.
M. Abe et. al., Nuclear Inst. and Methods in Physics Research A 890, 51 (2018)
• Requirements– Detection of e+ (100<E<300 MeV)
– Reconstruction of momentum vector
– Stability over rate changes�1.4 MHz à 14 kHz�
• Specifications– Sensor: p-on-n single-sided strip
– Number of vanes: 40
– Number of sensors : 640
– Number of strips : 655,360
– Area of sensors : 6.24 m2
Positron tracking detector
29
¼ vane
φ590 mm
750
mm
200 mm
First test module tested with muon at J-PARC
30June 2017
e+ track reconstructionwith positron tracking detector
31
Y. SatoLow rate (0.6 track/ns)
High rate (6 track/ns)
Simulation
Simulation
Reconstruction efficiency8. DETECTOR AND RECONSTRUCTION 35
Positron energy [MeV]0 50 100 150 200 250 300 350
Find
ing
effic
ienc
y
0
0.2
0.4
0.6
0.8
1 0.06 tracks/ns
0.6 tracks/ns6 tracks/ns
Positron energy [MeV]0 50 100 150 200 250 300 350
Rel
ativ
e fin
ding
effi
cien
cy
0
0.2
0.4
0.6
0.8
1 0.6 tracks/ns
6 tracks/ns
Figure 27: Track finding efficiency as a function of positron energy in different conditions onthe positron track rate (left) and track finding efficiency respect to the sample of track rate of0.06 tracks/ns (right). The detector with 48 vanes are used and the effect of readout ASIC is consid-ered.
and fitting separately the different energy-sorted time histograms, one can increase thestatistical power of the data and reduce the sensitivity to a change in efficiency vs time. Inthat case, an energy-sorted histogram having a rate-changing efficiency would only look likea varying slow term, which can be removed by the ratio analysis or the spin-flip technique.This presumes that any track-assigned momentum – once found and fitted – does not dependon any rate-related background; it seems to be a good working assumption.
We studied energy-sorted counting method and estimated statistical uncertainty. To demonstrate it,histograms of the number of positrons are separated into several energy bins. Each histograms arefitted and the resulting uncertainties on ωa are combined statistically. Figure 28 shows this result. Asincreasing the number of energy bins, the statistical uncertainty on ωa is reduced. We are going toadopt this method as an alternative counting method (see Section 12.1.5 of TDR).
8.7 Number of vanes
Recommendation-36: It was not clear to the committee that the number of vanes inthe proposed detector configuration was optimized. Given the high cost of the tracker, avalue engineering exercise should be carried out. There are many other implications besidescosts; e.g., heat load, data load, current draw.
We have reviewed the number of vanes in various aspects since the focused review. Figure 29 shows theestimated track finding efficiency as a function of the number of vanes. In terms of track reconstructionefficiency, we need at least 24 vanes to have efficiency above 80% in the highest pileup condition. Wewould like to realize 48 vanes at which more than 90% efficiency is expected even in the highest pileupcondition. Other quantities for 48-vane detector are summarized in Table 5 and they are manageable.
Design of 48-vane detector has been started and potential issues were identified (weight and mechanicalsupport of thin vanes). We build 24 vanes first to gain experiences. Then, we will extend to 48 vanesto complete the detector construction.
Responses to recommendations given by the focused review committee, Dec. 2017
Yamanaka + Sato
32
used forg-2 analysis
Simulation
Reconstruction of muon beam distribution
33300− 200− 100− 0 100 200 300
x [mm]
300−200−
100−0
100200
300y [mm]
250−200−150−100−50−
050
100150200250
z [m
m]
300− 200− 100− 0 100 200 300x [mm]
300−
200−
100−
0
100
200
300
y [m
m]
0 1 2 3 4 5 6 [rad]φ
250−
200−
150−
100−
50−
0
50
100
150
200
250
z [m
m]
Fig. 13 All reconstructed hits from 25 muon decays obtained from simulation projected
onto horizontal (x-y) plane (bottom left) and in φ-z plane (bottom right), and perspective
view in three-dimensional space (top) are shown. There are two positron tracks in the energy
range of 200 MeV< E <275 MeV. Track candidate hits are shown by colored dots and the
other hits are shown by white dots. Reconstructed track orbits are shown by colored curves
(top and bottom left) and straight lines for track finding are shown (bottom right).
17/22
Y. Sue, et al., JPS meeting (Sep 2018)Muon beam (truth)
������
������
������
e+ trackback
������
after unfolding
MC truthtrack backafter unfolding
������
Simulation data
34
B-field shimming test with the MuSEUMmagnet (1.7 T) at J-PARC
No shim�2015/05/19!
3!
! 860 ppm p-p�
in 50 cm DSV �
Field shimming by iron arraysAfter shimming #3�
2015/05/19!
! Measured by single probe system ! Spheroid : r=100 mm, z=300 mm�
22! 35
After shimming
Before shimming
Plots by K. Sasaki
B(μT)
azimuthal angle (rad)
axial position (mm)
r = 140 mm
B(μT)
azimuthal angle (rad)
axial position (mm)
400 ppm
0.4 ppm
-600 ppm
-0.5 ppm
Cross calibration of B-field probes
36ANL, March 27 2018
J-PARCProbe
FermilabProbe
Workshop on muonium
37
Osaka University, Dec 10-11, 2018http://www-kuno.phys.sci.osaka-u.ac.jp/muonium2018/
• Topics• BSM in muonium (M. Yoshimura, M. Endo)• Muonium HFS (M. Eides, D. Nomura, K. Shimomura)• Muonium 1S-2S (Y. Liu, P. Crivelli, S. Uetake)• Muonium Lamb shift (A. Olin)• Muonium for cLFV, g-2/EDM …
Summary• The J-PARC muon g-2/EDM experiment will measure g-2 and
EDM with completely different method.
• Features:• Low emittance muon beam (1/1000)• No strong focusing (1/1000)• Good injection eff. (x10)• Compact storage ring (1/20)• Tracking detector with large acceptance• Completely different from BNL/FNAL method
• We are moving to R&D to construction phase.• In coming years,
– Construction of muon beamline (H-line)– Demonstration of “muon cooling”– Re-acceleration to 1 MeV 38