ALP searches at IAXO, The International Axion Observatory

ALP searches at IAXO, The International Axion ObservatoryJavier Redondo

Thursday, 23, October,2014

Outline

- axion-like particles (ALPs) in PBSM

- “hints” of the existence of ALPs- strong CP and axions- stellar evolution- TeV-gamma-ray transparency of the universe- Dark Matters

- Solar heliosopes, IAXO


IAXO is an Axion-like particle detector

- B’s of order 3 T, - L’s of order 20 m- order Zero backgrounds

Axion-like particle �

L� 2 �g��4

Fµ⌫eFµ⌫�

(small mass and small coupling to two photons)

X-ray detector

ALPs are produced inside the Sun via the two photon coupling (and others) and scape easily

X-ray lens

Shielding

S

N

Helioscope idea, Sikivie PRL 1986

�

p+, e�,↵2+


Global continuous symmetry spontaneously broken at high energy scale Mimplies a low mass particle (Nambu-Goldstone boson) with weak couplings

Theory provides us with ALP candidates

pseudo Nambu Goldstone bosons

g ⇠ ↵

2⇡M Existing examples:

Hypothetical fancies: axion, majoron, R-axion, familons, and a loooong etc.

⇡0, ⌘, ⌘0, ...

Scalars and pseudoscalars that govern the sizes and deformations of extra dimensions, gauge couplings,etc... (typically there are O(100) of these)

Moduli, Radion, Dilatons

stringy ‘axions’ & string Axiverse

g ⇠ ↵

2⇡Mstring

Arvanitaki, Dimopoulos Phys.Rev. D81 (2010)


http://arxiv.org/find/hep-th/1/au:+Arvanitaki_A/0/1/0/all/0/1

http://arxiv.org/find/hep-th/1/au:+Arvanitaki_A/0/1/0/all/0/1

http://arxiv.org/find/hep-th/1/au:+Dimopoulos_S/0/1/0/all/0/1

http://arxiv.org/find/hep-th/1/au:+Dimopoulos_S/0/1/0/all/0/1

Phenomenology offers some hints - I Strong CP problem

However, NO neutron Electric Dipole Moment, nor any other sign of P, T or CP violation in the strong interactions has ever been measured !!

L✓ =↵s

8⇡trn

Gµ⌫a

eGaµ⌫

o

✓ ✓ < 10�11

We expect P and T to be violated in a generic QCD-like theory, the size of the violation is set by :

the theta angle,

Peccei-Quinn-Weinberg-Wilczek showed that a pseudo Nambu-Goldstone boson, solves the problem

Ve↵L✓ =

↵s

8⇡trn

Gµ⌫a

eGaµ⌫

o

✓

✓ +a

fa

◆

�⇥ �3 ⇥4

�⇥2

�⇥4

0 ⇥4

⇥2

3 ⇥4

⇥

✓ +haifa

Peccei,Quinn 1977, Weinberg 1978, Wilzcek 1978

- Relevant AXION couplings to SM particles, always suppressed by 1/fa

- Mixing with pseudoscalar mesons gives the AXION a mass

ma ' m⇡fifa

' 6meV109GeV

fa

a

� q,N, e

✓


Phenomenology offers some hints - II White dwarf cooling

⌫, ⌫̄

a?�

Axion emission can accelerate the WD cooling between neutrino and surface dominated cooling periods.

WD luminosity function

Nu

mb

er

of

WD

s/ V

ol &

Lu

min

osi

ty

-log luminosity

Period decrease of G117−B15A

pe

rio

d d

ec

rea

se r

ate

Miller Bertolami, Isern et al. arXiv:1406.7712Corsico et al. arXiv:1205.6180

gae/10�13

2.8 5.6

gae ⌘Ceme

faZ

ea

gae = 0, 1.4, 2.8 (10�13)


http://arXiv.org/pdf/1410.1677.pdf

http://arXiv.org/pdf/1410.1677.pdf

Phenomenology offers some hints - II Tip of M5’s RGB

⌫, ⌫̄a?

Axion emission delays the Helium flash makes Red giants grow brighter

gae ⌘Ceme

faZ

ea

Viaux, Redondo, Raffelt et al arXiv:1311.1669

M5 color-magnitude diagram


http://arXiv.org/abs/arXiv:1311.1669


Phenomenology offers some hints - II neutron star cooling

Leinson, arXiv:1405.6873

n+ n !3 P2 + a (coupling to neutrons)

CAS A neutron star observations for 10 years (Chandra)- Evidence for n cooper pairing + neutrino emission? ... factor of 2 missing


Phenomenology offers some hints - III

Transparency of the universe to gamma rays

Gamma rays pair-produce electron/positron pairs from the extragalactic background light ... some cannot arrive to earth

However, they do ...(Roncadelli et al PRD 84, Sanchez-Conde et al JCAP 1111, Horns and Meyer JCAP 1202)

Excess persists at

2� 4�




http://arXiv.org/abs/arxiv:1211.6405

http://arXiv.org/abs/arxiv:1211.6405

Phenomenology offers some hints - III

Transparency of the universe to gamma rays and ALPs

Photons can convert into ALPs in galactic or extra galactic magnetic fields and reconvert back close to us

Points to ALP couplings (Meyer 2012)

g�� ⇠ 10�11GeV�1

Requires ~neV ALP masses


http://arxiv.org/abs/1302.1208

http://arxiv.org/abs/1302.1208

Phenomenology offers some hints - IV Dark stuff

Cosmology demands 2(3) new substances: (the 3 of them can be ALPs)

- Dark Energy (very weakly coupled or chameleons)- Dark Radiation (only hints so far)- Dark Matter (cold or mildly warm; non-thermal)

Ne↵ = 3.90± 0.44(1�)

⌦DE = 0.73(3)

⌦cDM = 0.22(3)

PDG 2012; Nollet and Holler arXiv:1112.2683


Axion/ALP hot/warm Dark Matter

ALPs are thermally produced in the early universe by a number of processes

�

q

Cadamuro, Redondo arXiv:1110.2895

they can also decay and affect cosmology � ! ��

If light, they should be a subdominant component of DM ⌦

hDM,a

⌦DM,obs

< 0.03Hannestad et al. JCAP 1008

Or Dark radiationCadamuro arXiv:1110.2895Ne↵ ⇠ 0.04

Moduli decay into ALPs can be much more efficient Ne↵ ⇠ O(4)

Takahashi arXiv:1201.4816 , Conlon, arXiv:1208.3562

They can explain the 3.5 keV lineJaeckel, Redondo, Ringwald arXiv:1402.7335

+ soft X-ray excess + 3.5 keV line!!






http://arXiv.org/abs/1201.4816v2

http://arXiv.org/abs/1201.4816v2





Axion/ALP cold Dark Matter

�(x) = ⇢(x)eia(x)f

aVacuum realignment mechanism V (�) =

�

4

(|�|2 � fa)2+ ⇤

4

✓1� cos

✓a

fa

◆◆

- Early times mat<1, vacuum homogeneizes (modes kt<1 decay)

- At mat~1, a rolls to its minimum and oscillates

⇢cDM

⇠ ⇤4

✓R

osc

R(t)

◆3

energy density redshifts as CDM!

a = 0

a =⇡

2

a =3⇡

2a = ⇡

a = 0

⇡

String-wall decay

- Cosmic strings form- Scaling #/horizon~1- Oscillations and loop decay

-> axions (k~1/t )

- At mat~1 walls collapse the strings -> more axions


EBL

EBL

xion

Optical

X!Rays

CAST"Sumico HB

Τ

!5 !2 1 4

!15

!12

!9

Log10 mΦ !eV"

Log 10g!GeV

!1 "

EBL

EBL

xion

Optical

X!Rays

CAST"Sumico HB

Τ

!5 !2 1 4

!15

!12

!9

Log10 mΦ !eV"

Log 10g!GeV

!1 "

ALP Cold dark matter Arias, Redondo et al : arXiv:1201.5902

⇢cDM

⇠ ⇤4

✓R

osc

R(t)

◆3

/ [m2

�f2

�]2m�3/2

� /pm�

g2��

Standard Inflation singles out initial conditionQ

CD

Axi

ons

QC

D A

xion

s3.5 keV line; Jaeckel, Redondo, Ringwald arXiv:1402.7335

Axion DM Axion DM

ALP DM ALP DM






The International Axion Observatory


IAXO is an Axion-like particle detector

- B’s of order 3 T, - L’s of order 20 m- order Zero backgrounds

Axion-like particle �

L� 2 �g��4

Fµ⌫eFµ⌫�

(small mass and small coupling to two photons)

X-ray detector

ALPs are produced inside the Sun via the two photon coupling (and others) and scape easily

X-ray lens

Shielding

S

N

Helioscope idea, Sikivie PRL 1986

�

p+, e�,↵2+


Solar Axion-like particle flux well understood

L� 2 �g��4

Fµ⌫eFµ⌫�

L� 2 g�e2me

[ ̄e�µ�5 e]@µ�

Photon-ALP coupling

Electron-ALP coupling

g�e = 10�13g�� = 10�12 1

GeV

Redondo arXiv:1310.0823




Detection: coherent Inverse Primakoff

S

N

⇤✓

1 00 1

◆+

✓0 �ga� |B|!

�ga� |B|! m2a

◆�✓A||a

◆=

✓00

◆.L� 2 �g��

4Fµ⌫

eFµ⌫� = g��E ·B�

In a B-field, ALPs and photons are NOT propagation eigenstates

Axion-Photon conversion probability after a length L

Small mass (Energy and mass independent)

P (� ! �) =

2g��B!

m2�

!2

sin2 m2

�L

4!

!

P (� ! �) !✓g��BL

2

◆2

⇠ 10�21⇣ g��10�12GeV�1

⌘2✓

B

3T

◆2 ✓ L

20m

◆2

Photons expected ... not many!

N�

dAd!dt⇠ 0.14

m2 year keV

✓g��

3⇥ 10�12GeV�1

◆4 ✓ B

3T

◆2 ✓ L

20m

◆2

N�

dAd!dt⇠ 14

m2 year keV

✓g��

3⇥ 10�12GeV�1

◆2 ✓ g�e3⇥ 10�13

◆2 ✓ B

3T

◆2 ✓ L

20m

◆2


Predecessors

SUMICO (Tokyo U.)

CAST (CERN)

B-field ~ 4 TL ~ 2.3 m

B-field ~ 9 TL ~ 10 m


Sensitivity

Photon coupling arXiv:1307.1985

Electron (production) + Photon (det.) couplingarXiv:1302.6283






How much better than CAST can we do?

(2011) Towards a next generation axion helioscope, arXiv:1103.5334

... New TOROIDAL magnet, AREA!, optics, detectors

ATLAS toroid

NGAH

MagnetDimensions

Background

Meas. time

S/B improvement

X-ray opticsultra-low back. MICROMEGAS detectors




IAXO, International Axion Observatory

http://iaxo.web.cern.ch/iaxo/

(2014) IAXO Conceptual design report arXiv:1401.3233 (LOI submitted to CERN, but location open)- 90 signatures, 38 Institutions (CAST + new collaborations), Europe, US, Japan, Korea- Next steps: Memorandum of understanding, apply for funding!- R&D already going on (magnet,optics,detectors)

magnet design (CERN/Saclay)

optics (LLNL,DTU)

detectors (Zaragoza U./Saclay)






IAXO sensitivity

Igor Irastorza (talk at Patras 2014) link

g�� [GeV�1]

m�[eV]


https://indico.cern.ch/event/300768/session/0/contribution/80/material/slides/1.pdf

https://indico.cern.ch/event/300768/session/0/contribution/80/material/slides/1.pdf

Direct Axion/ALP DM searches in IAXO

w

h

LTE101

�2 �1 0 1 2

�2

�1

0

1

2

x[m]

y[m]

Many such cavities can be fit in IAXO (Redondo, Patras 2014)

+ Dish-Antenna experiments to search for transients

DM Axions convert into MW photons in a resonant cavity (mass oriented design)

- prediction on miniclusters of axion CDM

Zurek et al 07, See also Kolb & Tkachev 94

Mmc ⇠ 10�12M�

⌦mc/⌦aCDM ⇠ O(1)

(Horns et al JCAP1304016, Jaeckel & JR JCAP1311016, PRD 88, 2013)


Direct Axion/ALP DM searches in IAXO

ga� = c�↵

2⇡fa


Can IAXO clarify the hints? ... yes!

IAXO can find the axion up to - Through the photon or electron couplings- In this range, IAXO can measure, coupling and mass

Strong CP problem

ma & 1 ⇠ 10meV

WD,RG,NS cooling

If the axion is responsible, IAXO can find it If it is an ALP, it can strongly depend (photon coupling might be very small)

ma & 1 ⇠ 10meV

Transparency of the universe due to ALPs

IAXO will settle this issue (recall ) g�� ⇠ 10�11GeV�1 ,m� . neV

Dark matter

- In the strong CS&DW-contribution scenario, , IAXO is the only experiment proposed up-to-date that can find these axions. - Also if they are s sub-dominant contribution of DM- Direct DM search can reach sensitivities to detect axions and cover huge ALP parameter space

ma ⇠ meV

Dark radiation

- Discovering the axion or an ALP immediately implies a DM and DR candidate


Documents

ALP searches at IAXO, The International Axion Observatory