Tokyo axion helioscope experimentand

other axion experiments

Y. InoueInternational Center for Elementary Particle Physics, The University of Tokyo

for the Sumico Collaboration

Rencontres de Moriond EW2011, 18 March 2011, La Thuile, Italy

Collaborators

M. Minowa, R. Ohta, T. Mizumoto, T. HorieDepartment of Physics, School of Science, The University of Tokyo

Y. InoueInternational Center for Elementary Particle Physics, The University of Tokyo

A. YamamotoHigh Energy Accelerator Research Organization (KEK)

Logo designed by −→Yuki AkimotoGraduate School of Medicine, The University of Tokyo

Outline

• Introduction

– What & how we are going to detect?

• Tokyo axion helioscope

– Hardware, results & prospects

• Other experiments

– CAST

– Crystalline detectors

– Microwave cavity (axion haloscope)

• Conclusions

Introduction

Strong CP problem

Two independent sources of CP violation in QCD:

Lθ̄ =θ̄

32π2Fµν

a F̃aµν , θ̄ = θ + arg detMq,

where{

θ ← initial QCD ground stateMq ← quark mass matrix (EW scale physics)

⇑r⇓

Neutron EDM:

dn < 2.9× 10−26 e cm (θ̄ < 10−10)

Peccei–Quinn mechanism

Global chiral U(1)PQ + SSB −→ Axion (NG boson)

+ Making θ̄ into a dynamic parameter which should fall into thepotential minimum:

θ̄ = θ + arg detMq +a

fa

Axion mass:

ma =√

z

1 + z

fπmπ

fa

-πfa 0 πfa

a

V [a]

@@@I

θ̄ = 0

Axion-photon coupling

The axion couples to two photons:

Laγγ = −14gaγaFµν F̃µν = gaγa~E · ~B

gaγ =α

2πfa

[E

N− 2(4 + z)

3(1 + z)

]

= 1.9× 10−10( ma

1 eV

)[E/N − 1.92][GeV−1]

Model dependent factor:

E/N = 0 (std. KSVZ), 8/3 (GUT DFSZ).

E = Tr(QPQQ2em), N = Tr(QPQQ2

c)

Exclusion plot (gaγ–ma)

gaγ

[GeV

-1]

ma [eV]

10-16

10-15

10-14

10-13

10-12

10-11

10-10

10-9

10-8

10-7

10-6

10-6 10-5 10-4 10-3 10-2 10-1 100 101

Axion Helioscope

Axion models

E/N = 0 (K

SVZ)

E/N = 8/3 (G

UT-DFSZ)

Solar age

HB stars

Crystal solar axion

Microwave cavity

Laser

Axion helioscope[P.Sikivie, PRL51,1415(1983)]

The sun can be a powerful source of axions.

Primakoff process

photon axion

Ze ← Laγγ = gaγa~E · ~B → MagneticField

axion photon

Axion helioscope[P.Sikivie, PRL51,1415(1983)]

0

2

4

6

8

10

0 2 4 6 8 10 12

ax

ion

flu

x [

10

10cm

-2s-1

keV

-1]

E [keV]

×(gaγ/10-10

GeV-1

)2

Conversion rate:

Pa→γ . 14g2

aγB2L2

Sensitivity:gaγ ∝ (BL)−

12

(bg rate

time× area

) 18

Buffer gas — to reach out for heavier axions

Conversion rate:

Pa→γ =g2

aγ

2

∣∣∣∣∣∫ L

0

Beiqzdz

∣∣∣∣∣

2

.g2

aγB2L2

4,

q = kγ − ka ≈m2

γ −m2a

2E.

In vacuum, coherence is lost for ma &√

πE/L. . .

⇓

The effective photon mass in buffer gas:

mγ =√

4παNe

me.

Ne: electron density

0 0.05 0.1 0.15 0.2 0.25P

a→

γm

a [eV]

vacuum with buffer gas

Tokyo axion helioscope

Tokyo axion helioscope (Sumico)

Sumico V detector

• B = 4T, L = 2.3m

• 268A persistent current

• 16 PIN photodiodes

• Track the sun ∼ 12 hours/day

Gas handling system

PIN photodiodes

PV PV

heat exchanger (40K, 5K)

evacuatedline

rupture disc

diaphragm pump

exhaust

PC1

PC2

TCP/IP

EIA232

He gas

vacuum vessel

DAC cardPCI

+amp

piezo valvesPV−1000

Yokogawa MU101

HORIBASTEC

(5K)

gas container (5K)x−ray window

Helium density time chart

400

450

500

550

600

Dec Jan Feb Mar Apr0.8

0.9

1

hel

ium

den

sity

[m

ol/

m3 ]

ph

oto

n m

ass

[eV

]

5meV

3days

start

(encoder broken)end

quench

end of the 1stunmanned tracking

2nd unmanned tracking

2007 2008

PIN photodiode X-ray detector

• Inside OFHC shield @ T = 60K

• 16 PIN photodiodes4 PIN/module

• chip:Hamamatsu S3590-06-SPL

• size:11× 11× 0.5mm3/PIN

• active area > 9× 9 mm2/PIN

• inactive surface < 0.35µm

[T.Namba et al., NIMA489(2002)224][Y.Akimoto et al., NIMA557(2006)684]

Energy spectrum

0

1

2

3

4

5

6

7

8

0 5 10 15 20

cou

nt

rate

[10

-4k

eV-1

s-1]

E [keV]

solarbackground

-3

-2

-1

0

1

2

3

0 5 10 15 20

sola

r –

bg

[10

-4k

eV-1

s-1]

E [keV]

fit

Upper limit 95% CL (mγ=ma=1.004eV)

χ2(ma) =

mγ,maxXmγ=mγ,min

20 keVX

E=4 keV

»Nsolar(E, mγ)−Nbg(E, mγ)−Ntheo(E, q)

σ(E, mγ)

–2

Exclusion plot[Y.Inoue et al., PLB668(2008)93]

5×10-10

1×10-9

2×10-9

3×10-9

0.8 0.9 1

gaγ

[GeV

-1]

ma [eV]

Upper limit (95% CL)

χ2(ma) =

mγ,maxXmγ=mγ,min

20 keVX

E=4 keV

»Nsolar(E, mγ)−Nbg(E, mγ)−Ntheo(E, q)

σ(E, mγ)

–2

Sumico results & prospect

gaγ

[GeV

-1]

ma [eV]

10-11

10-10

10-9

10-8

10-3 10-2 10-1 100 101

PLB434(1998)147 PLB536(2002)18PLB668(2008)93

Phase I (vacuum) Phase IIPhase III latest

Phase IIIprospect

Sumico

Axion modelsE/N =

0 (KSVZ)

E/N =

8/3 (GUT-D

FSZ)

Solar age

HB stars

SOLAX, COSME, CDMS

DAMA (90%)

CAST vacuum

4He3He

Lazarus

Phase III upgrades, troubles & status

3 Introduced a cryogenic rupture disk (Done)

3 Automated gas density control (Done)−−−−−−−−−−−−−−−−−−−−−−−Sumico 2007–2008 run −−−−−−−−−−−−−−−−−−−−−−−

3 Reworked He pipelines for quicker evacuation (Done)

3 Thermoacoustic oscillation at higher ρHe

→ Introduced a blind-end bellows at Troom section (Resolved)

• Thermal non-uniformity at higher ρHe

→ Introduced new heat exchangers (Testing)

3 1st X-ray window got a puncture/crack→ Repaired by the manifacturer (Test passed)

8 2nd Spare window broken entirely by thermal stress (Alas!)

Phase III upgrades, troubles & status (gallery)

©©¼New heat exchangers

¢¢

¢®

Light shinningthrough the

2nd X-ray window

1st X-ray windowrepaired

with epoxy

?

Other experiments

CAST (CERN Axion Solar Telescope)[K.Zioutas et al., PRL94,121301(2005)]

• B = 9 T, L = 9.26m (LHC test magnet)

• Vertical ±8◦, horizontal ±40◦

• TPC, Micromegas, CCD X-ray telescope

Sumico & CAST side-by-side

Sumico CAST

Tokyo CERN

4T× 2.3m 9T× 9.26m

12 hours/day 2× 1.5 hours/day4He @ 5 K (ma . 2 eV) 4He,3He @ 1.9 K (ma < 1.1 eV)

CAST result

From[J.Galan, arXiv:1102.1406]

Crystal detectors[R.J.Creswick et al., PLB427(1998)235]• Primakoff conversion

in a lattice

• Bragg condition:

2d sin θ = nλ

θθ

d

axion photon

• SOLAX — Ge [A.O.Gattone et al., NPB-PS70(1999)59]

gaγ < 2.7× 10−9GeV−1 (95%)

• COSME — Ge [A. Morales et al., Astropart. Phys. 16(2002)325]

gaγ < 2.78× 10−9GeV−1 (95%)

• DAMA — NaI(Tl) [R.Bernabei et al., PLB515(2001)6]

gaγ < 1.7× 10−9GeV−1 (90%)

• CDMS — Ge [Z.Ahmed et al., PRL103,141802(2009)]

gaγ < 2.6× 10−9GeV−1 (95%)

Microwave cavity (axion haloscope)[P.Sikivie, PRL51,1415(1983)]

0B

a hνm

Laγγ = gaγa~E · ~Bhν = γma,

⟨β2

⟩ ∼ 10−6

1GHz = 4.14 µeV

Power =g2

aγV B20ρhaloCmode

mamin(Qcavity, Qhalo)

gaγ ∝ B−10 V −1/2T

1/2noise

Pioneers: Rochester-BNL-FNAL (RBF), Florida (UF)

ADMX (Axion Dark Matter eXperiment)[S.J.Asztalos et al., PRL104,041301(2010)]

http://www.flickr.com/photos/llnl/4305091276

• LLNL

• B0 = 7.6T

• GaAs HFET (Ts ∼ 2K)

→ dc SQUID (Ts = 47mK @ 700 MHz)

• Scanned ma = 1.9–3.53 µeV

• Next upgrade: Tcavity ∼ 2K→ 100mK

CARRACK(Cosmic Axion Research with Rydberg Atoms in resonant Cavity in Kyoto)

[M.Tada et al., NPB-PS72(1999)164]

• Microwave photon counting using Rydberg atoms39K, 85Rb, etc.; ns→ np, n = O(100–200)

• B = 7 T, Tcavity = 10 mK

• Goal: cover ma = 8–30 µeV up to gaγ ∼ DFSZ prediction.

http://www.ltm.kyoto-u.ac.jp/newcarrack/

γaxion

laser

e

g

strong magnetic fieldfree frommagnetic field

selectivefieldionizationdetector

electrondetector

conversion cavity detection cavity − V

0e

ion

BextRydberg atoms

gαγγ

[M.Tada et al., arXiv:physics/0101028]

Exclusion plot

gaγ

[GeV

-1]

ma [eV]

10-16

10-15

10-14

10-13

10-12

10-11

10-10

10-9

10-8

10-7

10-6

10-6 10-5 10-4 10-3 10-2 10-1 100 101

Phase I Phase II

Phase III latest

Sumico

Axion models

E/N = 0 (K

SVZ)

E/N = 8/3 (G

UT-DFSZ)

Solar age

HB stars

SOLAX, COSME, CDMS

DAMA

CAST

CAST 4He

CAST 3He

Lazarus

AD

MX

UF+RFB

CA

RR

AC

K g

oal

Laser

Conclusions

• 2 Fronts of experimental axion searches:

– Solar axion ma ∼ O(eV)Sumico, CAST, crystals

– Dark matter axion ma ∼ O(µeV)ADMX, CARRACK

• Sumico Phase III

– Sumico 2007–2008 result:

gaγ < 5.6–13.4× 10−10GeV−1 (0.84 < ma < 1.00 eV)

– Upgrading toward ma . 2 eV

Backup

Axion-photon oscillation[Raffelt & Stodolsky, PRD37(1988)1237]

Wave equation for (A⊥, A‖, a) plane wave propagating along thez axis:

ω2 + ∂2z −m2

γ 0 00 ω2 + ∂2

z −m2γ gaγBω

0 gaγBω ω + ∂2z −m2

a

A⊥A‖a

= 0.

↓A‖ ­ a mixing

Notes on buffer gas• 4He is used ⇐⇒ CAST is using 3He

• Temperature is kept high enough above the critical point(pc = 0.227MPa, Tc = 5.1953K)

• X-ray absorption and decoherence due to gravity are not fataleven at mγ ∼ 2 eV

mγ =√

4παNe

me

−→

0

0.5

1

1.5

2

2.5

3

3.5

0 0.05 0.1 0.15 0.2 0.25 0.3

effe

ctiv

e p

ho

ton

mas

s [e

V]

pressure [MPa]

4He T=6K

rup

ture

dis

k

X-r

ay w

ind

ow

safety region

Buffer gas container

• Welded 4 ×st. steel 30421.9× 17.9× 2300 mm3

square pipes

• Wrapped with99.999% pure Al0.1-mm thick × 2 layers

• Thermal conductivity(measured)& 10−2W/K @ 5 K, 4 T

X-ray window

Metorex C10 window(custom)

• 25µm Be foils with 1µm polyimide coating

• Supported by Ni grid

• Withstands up to 0.3 MPa

• Transmits & 80% for E > 3keV

Internal calibration source

55Fe (5.97 keV)

Internal calibration source

55Fe (5.97 keV)

Data acquisition system

preamp

Clear PulseCP4026

TechnolandN-TM405

discr.

shaper

HoshinC005

inpu

t reg

iste

r

Q

LAMLAMO

PINVETO

TechnolandN-TM203

delay

fan out

scaler

TechnolandC-TS203

VETO

ch0clock1 kHz

N-TM203

FADC

clock10MHz

clock

in

stop

REPICRPC-081

bipolar3us

LAM

hit pattern

CA

MA

C b

us

live time

wave form

1 Kwords/ch

50us

fan out

fan out

100 sµ

home-made

home-made

16ch • 16 input channels

• Waveform recording:PIN photodiode↘ Charge sens. preamp.↘ Flash ADC

• Offline shaping

• Trigger:shaper + leading edge discr.

• Precise live time

• Control: CAMAC

Sumico results & prospect

3 Phase I — vacuumSumico 1997 run: [S.Moriyama et al., PLB434(1998)147]

gaγ < 6.0× 10−10GeV−1 (ma < 0.03 eV)

3 Phase II — low density 4He (ρHe . 105Pa/298K)Sumico 2000 run: [Y.Inoue et al., PLB536(2002)18]

gaγ < 6.8–10.9× 10−10GeV−1 (0.05 < ma < 0.27 eV)

+ Phase III — high density 4HeSumico 2007–2008 run: [Y.Inoue et al., PLB668(2008)93]

gaγ < 5.6–13.4× 10−10GeV−1 (0.84 < ma < 1.00 eV)

Upgrades are continuing. . .Goal: p . 0.1MPa @ T = 6K →ma . 2 eV

Pioneering axion helioscope[Lazarus et al., PRL69,2333(1992)]

• BNL-Rochester-FNAL

• B = 2.2T, L = 1.8m, fixed dipole magnet

• He gas (0, 50, 100 Torr)

• Proportional chamber (Ar 90% CH4 10%)

• 15 minutes/day (sunset)

• gaγ < 3.6× 10−9GeV−1 for ma < 0.03 eV,

gaγ < 7.7× 10−9GeV−1 for 0.03 eV < ma < 0.11 eV.

cf. Solar age: gaγ < 2.4× 10−9GeV−1