--- a part of ---RIKEN J-PARC CENTER
PROJECT
RNC
M. IWASAKI

--- a part of ---Future Projectof the
Sub Nuclear System
Research Division

Proposal ofMuon g-2 R&D as a New Pillar
at RIKEN-RAL

Organization structure for Riken-RAL BranchOrganization structure for Riken-RAL BranchOrganization structure for Riken-RAL BranchOrganization structure for Riken-RAL BranchSpin Physics at BNL
Hadron Physics at KEK-PS
Muon Science at RAL
Hadron Physics at KEK-PS

Organization structure for Riken-RAL BranchSpin Physics at BNL
Hadron Physics at KEK-PS
Muon Science at RAL
Hadron Physics at KEK-PS

Organization structure for Riken-RAL BranchSpin Physics at BNL
Hadron Physics at KEK-PS
Muon Science at RAL
Hadron Physics at KEK-PS

Organization structure for Riken-RAL BranchSpin Physics at BNL
Hadron Physics at KEK-PS
Muon Science at RAL
Hadron Physics at KEK-PS

RIKEN J-PARC Center

New Contract

Sub-Nuclear System RD
Hadron Physics・Confinement
Origin of Hadron Mass
ー 99.95% of the Material Mass is from Nuclei
ー Nuclei consist of proton and neutron
ー quark mass is only 1% of proton and neutron

Where other 99％ comes from？
Is Nanbuʼs Theory correct?
Major subject at J-PARC

Sub-Nuclear System RD
Particle Physics :Standard Model
Precise muon g-2 measurement
ー significant deviation from SM by 3.7σphysics beyond the Standard Model?

Most crucial test
Even after LHC for Lepton sector

R & D onlySub-Nuclear System RD
Particle Physics
New Muon Source development
New generation Slow μ・RIKEN-RAL

Ultra-low emittance muon beam
to realize g-2 : high dens. & low temp. & laser

Hadron Physics
Hadron experiment Platform
Large Scale Detector at J-PARC

CURRENT PRECISION E821 at BNL-AGS

measured down
to 0.7 ppm forboth µ+ and µ− 3.7 σ deviationfrom the SM Need to explore!

BNL E821 EXPERIMENT

forward positron calorimeter

HOW WAS IT MEASURED?
Precise frequency of muon ωa in the storage

ring was measured at the magic momentum
flash!

WHAT IS THE MAGIC MOMENTUM?

WHAT IS THE MAGIC MOMENTUM?

=0 @ 3 GeV/c

WHAT IS THE MAGIC MOMENTUM?

=0 @ 3 GeV/c

Electric field is the origin of CBO
Horizontal vibration!

+V-V-V+V

WHAT IS THE MAGIC MOMENTUM?

=0 @ 3 GeV/c

Electric field is the origin of CBO
Horizontal vibration!
WHATʼS IF E=0?
No need for vertical focusing-V
if vertical divergence is extremely small!!

+V-V+VWHAT IS THE MAGIC MOMENTUM?

=
0 @ 3 GeV/c

Electric field is the origin of CBO
Horizontal vibration!
WHATʼS IF E=0?
No need for vertical focusing-V
if vertical divergence is extremely small!!
Ultra-Slow Muon

+V-V+VYIELD AND RE-ACCELERATION=€∫ A(η)n(η)dη∫ n(η)dηMUON G-2 MEASUREMENT(~300MeV/c)

MUON G-2 MEASUREMENT

F-B
F+B

(~300MeV/c)

MUON G-2 MEASUREMENT

F-B
F+B

γ = 3 @ 3T(~300MeV/c)

ADVANTAGE How can we free from systematic error?

ADVANTAGE How can we free from systematic error?
・ No pion contamination / No flash
・ Direct asymmetry measurement

F-B
F+B

A, ω, δ, R・ Momentum measurement with fine segmented detector
Free from pileup
・ Insensitive to gain drift
・ Free from Coherent Betatron Oscillation (CBO)Free from modulation of time spectrum due to CBOADVANTAGE How can we free from systematic error?
・ No pion contamination / No flash
・ Direct asymmetry measurement

F-BF+BA, ω, δ, R・ Momentum measurement with fine segmented detector
Free from pileup
・ Insensitive to gain drift
・ Free from Coherent Betatron Oscillation (CBO)Free from modulation of time spectrum due to CBO- DISADVANTAGE
・ Small yield at present
Drastic improvements needed for Laser System
・ Need to reduce emittance even further
High density & low temperature muonium generation

ADVANTAGE How can we free from systematic error?
・ No pion contamination / No flash
・ Direct asymmetry measurement

F-B
F+B

A, ω, δ, R

・ Momentum measurement with fine segmented detector
Free from pileup
・ Insensitive to gain drift
・ Free from Coherent Betatron Oscillation (CBO)Free from modulation of time spectrum due to CBO- DISADVANTAGE

・Positive muon only・ Small yield at present
Drastic improvements needed for Laser System
・ Need to reduce emittance even further
High density & low temperature muonium generation

TO REALIZE g-2
・ Muon Yield

x 104
x 10 : beam powere. g. 1MW - 3 GeV @ J-PARC

x 10 : solid angle
all solenoid beam channel

x 102 : laser power

・ Muonium Target< room temp.
better focus
SiO2 powderZeolite?

capillary focus?

NEW FRAMEWORKTIME SCALE FOR NEW SLOW MUON GENERATION
2~3 years
intensity x 100 or more / good emittance
IDEAL FOR μSR AT PULSE BEAM

Thank you

SM CONTRIBUTION TO a≠0

MUON G-2 IN THE LHC ERA
Even the first SUSY

discovery was made at
LHC, the muon g-2
measurement remains
unique to determine
SUSY parameters:
μ and tan βaµ (SUSY) ≈ (sgn µ)13 ×10−10

100 GeV tan β ˜m2