PRISM-II and Measurement of Muon Electric Dipole Moment

based on J-PARC mu-edm LoI

NuFACT-J'03

M. AokiOsaka University

Contents

◆Muon electric dipole moment◆Concept of the mu-edm measurement◆PRISM-II◆Muon storage ring◆Experimental Site◆Control of the systematics◆Summary

Leptogenesis

CPV in CKM is not enough to explain Baryon Asymmetry

→ New sources of CPV beyond the SM

Oscillation + CPV in lepton sector → leptogenesis

Fukugida & Yanagida ‘86

AND if SUSY exists → ・ muon EDM

・ T-violation in muon LFV

g-2 and mu-edm

◆General dipole moment, D

€

DNP = DNP e iφCP

dμNP ≅ 3×10−22 aμ

NP

3 ×10−9

⎛

⎝ ⎜

⎞

⎠ ⎟tanφCP e ⋅cm

SUSY with the Muonµeµeµeμ e µeµeµeμ e

μ~μ~

μ-LFV

μ-EDM g-2 μ-e conversion

μ → e md

ms

mb

⎛

⎝

⎜ ⎜ ⎜

⎞

⎠

⎟ ⎟ ⎟

mνe

mνμ

mν τ

⎛

⎝

⎜ ⎜ ⎜

⎞

⎠

⎟ ⎟ ⎟

m˜ d

m s

m˜ b

⎛

⎝

⎜ ⎜ ⎜

⎞

⎠

⎟ ⎟ ⎟

m e e 2 Δm e μ

2 Δm e τ

2

Δm μ e

2 m μ μ

2 Δm˜ μ τ

2

Δm τ e

2 Δm τ μ

2 m˜ τ τ

2

⎛

⎝

⎜ ⎜ ⎜

⎞

⎠

⎟ ⎟ ⎟

quark

lepton (neutrino) slepton

squarknormal particles SUSY particles

ex. K-decays, B-decays

ex. neutrino oscillation ex. charged lepton LFV

CPV

μ

µeµeµeμ e

μ~μ~

μ

g-2 and muon-EDM in SUSY

◆aμ(SM(DEHZ))-aμ(Exp) = (33.9±10.6)x10-10

◆dμ < 10-20 e.cm

Concept of the experiment

◆ Muon spin precession （相対）

第１項 外部磁場による mdm の回転 第２項 外部電場がローレンツ変換されてつく

る磁場による mdm の回転 第３項 edm の回転

◆ 第１項を第２項でキャンセルする◆ β×B による電場をつかう

€

ω =−e

maB +

1

γ 2 −1− a

⎛

⎝ ⎜

⎞

⎠ ⎟β × E

c+η

2

E

c+ β × B

⎛

⎝ ⎜

⎞

⎠ ⎟

⎧ ⎨ ⎪

⎩ ⎪

⎫ ⎬ ⎪

⎭ ⎪

a =g− 2

2, μ =

g

2

eh

2m, μ =

η

2

eh

2mc

◆キャンセル電場E=aBcβγ2 E=2 MeV/m 、 B=0.25 T

◆Edm 電場E=Bcβ B=0.25 T → E=72 MeV/m

€

ω =−e

maB +

1

γ 2 −1− a

⎛

⎝ ⎜

⎞

⎠ ⎟β × E

c+η

2

E

c+ β × B

⎛

⎝ ⎜

⎞

⎠ ⎟

⎧ ⎨ ⎪

⎩ ⎪

⎫ ⎬ ⎪

⎭ ⎪

PRISM for mu-edm

◆ Accelerate low energy muon upto 500 MeV/cInitial muon ~1011

Decay survivability ~6%Polarization ~0.2?NP2 = 108 毎秒

◆ 一方、dμ<10-24 e.cm → NP2>1016 total

PRISM

20 - 500 MeV

PRISM-2 for mu-edm

◆ Accept 500 MeV/c muons and phase rotate Initial muon ~2×1010

Decay survivability ~56%Polarization ~0.6NP2 = 109~1010 毎秒

Transverse 800 mm.mradMomentum acceptance ±30%

PRISM-2

PRISM-2 Muon decay channel

◆Curved solenoid1T, r=45cm, R=5m50deg curveTransmission

90% for 0.7 Gev/c-1.1 GeV/c pion

800 mm.mrad

350 MeV/c<pμ<650 MeV/c

PRISM-2 phase rotator

◆Use the 1st ring of Japanese NF as PRISM-2 phase rotator0.3 - 1.0 GeV

Mu-edm storage ring◆ <R>=10 m◆ B=0.25 T, E=2 MeV/m◆ 800 p mm.mrad◆ Δp/p=2%◆ Tune x=4.42, y=4.2◆ Beta function x=6.85 m, y=7.1 m

Experimental Site

Systematics

◆Non-planar (NP) systematicsE field at not in a median planeMuon orbit is not in a median plane

◆How to control?Inject muons into clockwise(CW) and count

er-clockwise(CC)Benchmark with deuteron beam

◆edm = muon edm ×β

◆Deutron NP = muon NP ×muon-γ2

E=aBcβγ2€

ω =−e

maB +

1

γ 2 −1− a

⎛

⎝ ⎜

⎞

⎠ ⎟β × E

c+η

2

E

c+ β × B

⎛

⎝ ⎜

⎞

⎠ ⎟

⎧ ⎨ ⎪

⎩ ⎪

⎫ ⎬ ⎪

⎭ ⎪

Summary

◆dμ < 10-24 e.cm → NP2 > 1016/year

◆Pμ(PRISM) > 0.3

◆Nμ(PRISM) > 1012 @500 MeV/c◆PRISM-2 ring (1st ring of the JNF)