Axions N Phenomenology of Detection N Direct Searches for Wimps IMFP2005,N Direct Benasque, Searches March for Axions 2005 Igor G

DirectDirect SearchesSearches forfor DarkDark MatterMatter ParticlesParticles

Igor G. Irastorza CEA/Saclay

International Meeting on Fundamental Physics 2005 Benasque, March 2005

Summary:

n The paradigm of Dark Matter n Candidates for DM: WIMPs and axions n Phenomenology of detection n Direct Searches for WIMPs IMFP2005,n Direct Benasque, Searches March for Axions 2005 Igor G. Irastorza / CEA, Saclay 1 DarkDark MatterMatter atat cosmologicalcosmological scalesscales n Important amount of observational evidence gathered up to now: – Multiple CMB observations – Distant Supernova Ia measurements (universe is accelerating its expansion à Dark energy). – Large Scale Structure (cold dark matter). – Nucleosynthesis, Lyman a forest, … n Last WMAP precision data adds evidence for LCDM cosmological model.

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 2 LLCDMCDM n The Universe is flat: “Dark – W = 1.02 ± 0.02 energy” n Precision Cosmology: (WMAP ~73% combined with others)

Baryonic non baryonic < 5% Visible < 1% Dark Matter WMAP, Astrophys.J.Suppl.148:1,2003 ~23 % IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 3 DarkDark MatterMatter Rotation curve of the Milky Way atat galacticgalactic scalesscales n Galactic rotation curves

They appear rather flat, evidencing matter beyond Rotation of galaxies the light distribution mesaured by Doppler shift n Gravitational mass of galaxy clusters (oldest evidence; 1933 Zwicky)

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 4 WhatWhat cancan DarkDark MatterMatter be?be? n Baryonic matter? NO – Dust, gas, planets, brown stars,… MACHOS (non visible conventional matter) – Ruled out by primordial Nucleo-synthesis, and the rest of cosmological observations. – Gravitational lensing of MACHOS à not enough n Non baryonic, but standard, matter? NO – Neutrinos would be the only candidate in the SM. Ruled out by cosmological observations (they would constitute Hot Dark Matter) n Non baryonic, beyond standard? most probable

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 5 CandidatesCandidates toto DarkDark MatterMatter n Two main candidates attract most of the present activity in the field: WIMPS n Like the LSP of supersymmetric theories Neutral (usually the neutralino). Heavy n WIMP stands for Weakly Interacting Massive Fermion Particle (generic name). n Axions appear as Nambu-Goldstone bosons in the PQ spontaneous symmetry breaking. AXIONS n More generically, we speak about axion-like Neutral particles, to refer to fundamental Very light (pseudo)scalars of similar properties without (pseudo)scalar referring to a specific theory model.

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 6 Dark Matter WIMPs detection

In order to do predictions of expected WIMP WIMP fluxes/signals one has to make galactic halo working hypothesis about how WIMPs are clustered in the galactic halo

Standard (=simpler) halo model Sphericity rW Isotropy Non-rotation WIMP and Thermalization phenomenology Non-Standard Mass f(v) Relaxing one or more of WIMP-nucleon at Earth the above assumptions cross section to some degree SD/SI coupling? Must explain rotation curve of Milky Way WIMP “wind” WIMPWIMP detectiondetection

232 kmEffect/s looked for at laboratory: Elastic dispersion of WIMPs with nuclei of detector

WIMP

nuclear recoil WIMP WIMPWIMP detectiondetection n Expected signal: nuclear rare low energy event recoil

0.5 Standard halo model 0.45 60 GeV 10-8 nbarn Specific challenges: 0.4 day Germanium / 0.35 semiconductor detector üLow threshold (~keV) kg / 0.3 üReasonable resolution 0.25 keV / 0.2 üVery low background at keV 0.15 scale: counts 0.1 0.05 üRadiopurity & rejection 0 techniques 0 5 10 15 20 25 30 üAim for large detector masses Visible energy (keV) üGreat stability over time. IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 9 WIMPWIMP detectiondetection

WIMP nuclear recoil

+ + - + - - + + - - - +

light charge heat

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 10 WIMPWIMP detection:detection: present efforts & projects EDELWEISS CUORICINO @Modane @GranSasso CDMS GENIUS @Soudan H/M @GranSasso CUORE @GranSasso @GranSasso ROSEBUD-I HEAT+ GEDEON @Canfranc IGEX-DM @Canfranc CHARGE CHARGE PICASSO @Canfranc @SNO CRESST-I MIMAC-He3 SIMPLE @GranSasso DRIFT @Grenoble HEAT @Rustrel @Boulby NEWAGE ORPHEUS @Kyoto @Bern HEAT+ LIGHT X-MASS @Kamioka XENON LIGHT+ CHARGE ZEPLIN-II @US CRESST-II @Boulby @GranSasso ROSEBUD-II WARP @Canfranc LIGHT ZEPLIN-I @GranSasso DAMA-NaI @Boulby @GranSasso ANAIS @Canfranc KIMS LIBRA DAMA-Xe NAIAD@YangYang @GranSasso @Boulby @GranSasso ELEGANTS @Oto IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 11 WIMPWIMP identificationidentification abilityability n WIMP spectrum is quite “feature-less”. Cannot evidence a WIMP signal (unless extremely above the expected background) n Most of present set-ups can only “reject” WIMPs, but not identify them. n Few kinds of positive signatures: – Annual modulation: BIG CHALLENGE. At reach (DAMA,…ANAIS, CUORICINO, CUORE, GENIUS, GEDEON,…) – Directional signal. VERY BIG CHALLENGE. Good progress (DRIFT, NEWAGE). Maybe at reach soon. – Target material dependence. VERY BIG CHALLENGE. Good progress (ROSEBUD-II, CRESST-II). Maybe at reach soon. – Diurnal variation. Some attempts in the past (COSME, SIERRA GRANDE). Very large statistics needed.

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 12 AnnualAnnual modulationmodulation signalsignal 232 km/s

0.5 Standard halo model 0.45 60 GeV 0.4 10-8 nbarn 0.35 Germanium

day semiconductor detector / 0.3 kg / 0.25

keV 0.2 / 0.15

counts 0.1 0.05 0 0 5 10 15 20 25 30 Energy (keV) DAMADAMA--NaINaI

n 100 kg of ultrapure NaI(Tl) operating for about 7 years at Gran Sasso n Looking for annual modulation of the data n 107731 kg day statistics gathered n Experiment out of operation in July 2002 to start work in LIBRA.

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 14 DAMADAMA positivepositive resultresult n Modulation detected along nNo systematic effect found that 7 years. can mimic that signal nModulation absent above 6 keV n 6.3s statistical significance.

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 15 DAMA Positive result: WIMP interpretation

n Is the DAMA positive signal already excluded by other experiments? ßpolemic point… n Modification of the region for non-standard set of assumptions…

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 16 OtherOther NaINaI experimentsexperiments that could refute/corroborate DAMA result n ANAIS in Canfranc: – First prototype successfully n LIBRA in DAMA: 250 kg just operated starting in Gran Sasso – 100 kg available, being instrumented

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 17 IonizationIonization detectors:detectors: IGEXIGEX--DMDM n Still the best raw (no discrimination) background achieved:

0.2 c/keV/kg/day between 4-10 keV

Best radiopurity & shielding conditions

IMFP2005, Benasque, March CANFRANC 2005 Igor G. Irastorza / CEA, Saclay 18 IonizationIonization detectors:detectors: IGEXIGEX--DMDM

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 19 FutureFuture largelarge ionizationionization detectorsdetectors

GEDEON GENIUS

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 20 HeatHeat ++ charge:charge: CDMSCDMS

n Nuclear recoils events ionize less that electron n Events from gamma recoils of same energy calibration (~25% for Ge) n They can be efficiently distinguished by comparing heat and n Events from charge signals down to a neutron calibration threshold of ~10 keV n Most powerful technique to reject WIMPs up to now.

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 21 CDMSCDMS n19.4 kg-d of Ge net exposure recently released (PRL 93 (04))

n Moved underground (Soudan) in 2003. n O events surviving cuts (10-100 keV), – while less than one of background expected (0.7 misidentified electrons and 0.07 neutrons) EDELWEISSEDELWEISS

n 3 x 320 g Ge bolometers in operation underground in Modane. n Last result (2003) released additional 45 kg·d (total 62 kg·d). n 40 nuclear events observed, above a threshold of ~15 keV. n Perspectives: multiply x10 the target mass (EDELWEISS-II) • Plots from the 1st run (2002)

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 23 n Both CDMS and EDELWEISS are working to increase their detector mass

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 24 Xe+ Ionisation +Xe Electron/nuclear recoil + Xe2 Excitation XenonXenon detectorsdetectors +e- (recombination) n ZEPLIN-I (at Boulby) measures Xe* Xe** + Xe

only scintillation. Statistical +Xe

discrimination of the nuclear Xe * 175nm 2 175nm recoils by pulse decay time. Triplet Singlet recoils by pulse decay time. 27ns 3ns n 293 kg´days of data 2Xe 2Xe n Moving to ZEPLIN-II which will measure both scintillation and charge.

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 25 FutureFuture XenonXenon experimentsexperiments

ZEPLIN-II (30 kg) X-MASS (3 kg à 1 ton)

ZEPLIN-III-IV (1 ton) XENON-10-100-1T

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 26 FutureFuture ofof WIMPWIMP detectiondetection n Build larger detectors and reduce backgrounds: CUORE, GENIUS, GEDEON,… à better exclusion plot & annual modulation signature n Pursue new ideas to achieve this: MacHe3, ORPHEUS, PICASSO, SIMPLE, spherical TPC(?) n Exploit new positive signatures: – Directional detectors: DRIFT, NEWAGE – Several material in same set-up: ROSEBUD-II, CRESST-II

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 27 CUORECUORE

n Double beta decay CUORICINO as main goal, but also dark matter (annual modulation)

CUORE

40.7 kg of TeO2 (largest mass of cryogenic detector presently operating !!) 988 crystals, 740 kg TeO2 IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 28 Heat+lightHeat+light ROSEBUD-II

BGO CRESST-II

n The technique that can exploit the material dependence signature. CaWO4 IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 29 NewNew ideas:ideas: thethe sphericalspherical TPCTPC

High Voltage n First prototype Shield working at Saclay

10 m Drift Gaseous Volume

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 30 NewNew ideas:ideas: thethe sphericalspherical TPCTPC n Natural focusing: Demonstration prototype built – large volumes can be instrumented and working in Saclay n Still some spatial information achievable (Signal time dispersion) n 5.9 keV 55Fe signal n Other practical advantages: – Symmetry: lower noise and threshold – Low capacity – No field cage n Simplicity: few materials. They can be optimized for low radioactivity. n Low cost Plans to develop a “radiopure” prototype in Zaragoza The way to obtain large detector volumes keeping low background and threshold

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 31 DirectionalDirectional signalsignal

Background is isotropic

IMFP2005, Benasque, March While the signal is not 2005 Igor G. Irastorza / CEA, Saclay 32 DirectionalDirectional detectorsdetectors

DRIFT-I DRIFT-I n 1m3 Dual Negative Ion DRIFT TPC n 1.4m3 vac vessel - 40 Torr CS2

n Constructed 2000, Installed 2001/2 DRIFT n Currently underground and taking data. - I @ Boulby

NEWAGE

DRIFT-II-…

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 33 AXIONAXION theorytheory motivationmotivation n Axion: introduced to solve the strong CP problem

Possible CP-violating term in QCD lagrangian:

( )

Two different contributions here: QCD vacuum and EW quark mixing Experimental consecuence: prediction of electric dipole moment for the neutron:

(A = 0.04 – 2.0)

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 34 AXIONAXION theorytheory motivationmotivation n But experiment says…

So, •Why so small?

•Hight fine-tunning of two different contributions required

Peccei-Quinn (1977) propose an elegant solution to this problem. q not anymore a constant, but a field à the axion a(x). Fine-tunning reached naturally, dinamically.

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 35 AXIONAXION theorytheory motivationmotivation n Peccei-Quinn solution to the strong CP problem •New U(1) symmetry introduced in the SM:

Peccei Quinn symmetry of scale fa •The AXION appears as the Nambu-Goldstone boson of the spontaneous breaking of the PQ symmetry

q absorbed in the definition of a

•a à qq transitions 0 axion – gluon •a – p mixing vertex •axion mass > 0

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 36 AXIONAXION phenomenologyphenomenology n The axion is…

üpseudoscalar üneutral üpractically stable PRIMAKOFF EFFECT üphenomenology driven by the

breaking scale fa and the specific axion model axion-photon coupling üCouples to photon: present in almost every axion model

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 37 AxionAxion SearchesSearches n Axions are searched in 3 different contexts (different sources of axions): – Dark matter axions (as relics of Big Bang): § Axion Haloscopes (ADMX, CARRACK) – Axions produced in the Sun: § Axion Helioscopes (Kyoto, CAST) § Crystal detectors (SOLAX, COSME, DAMA) – Axions produced in the laboratory § “Light shinning through wall” experiments § Vacuum birrefringence experiments (PVLAS positive signal!)

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 38 DarkDark MatterMatter AxionsAxions:: HaloscopesHaloscopes n Resonant cavities (Sikivie,1983) – Primakoff conversion inside a “tunable” resonant cavity 2 2 – Energy of photon = mac +O(b ) – Expected peak at right frequency (DM axions are non-relativistic) – Substructure of the peak may give information of the WIMP halo model

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 39 DarkDark MatterMatter AxionsAxions:: HaloscopesHaloscopes n ADMX in Livermore – Development of SQUID technology for 2nd phase n CARRACK in Kyoto. – Different detection approach: “single microwave quanta” detection.

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 40 HaloscopesHaloscopes sensitivitysensitivity ADMX

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 41 SolarSolar AxionsAxions n Solar axions produced by photon-to- axion conversion of the solar plasma photons axions Ø Solar axion flux [van Bibber PRD 39 (89)]

8×1014

1 14 - 6×10 V e

k Solar physics 1

- 14 c +

e 4×10 s

2 Primakoff effect - m c 2×1014 Only one unknown

parameter gagg 0 0 2 4 6 8 10 E(keV) SolarSolar AxionsAxions n Detecting Solar Axions with crystal detectors [Paschos/Zioutas PLB 323 (94)] n By means of Primakoff-Bragg effect: – The periodic structure of the crystalline E field and the movement of the Sun produces a very characteristic time patter axions that can be looked for. n 3 experiments have provided limits using this technique: SOLAX, COSME, DAMA

n Limits can be obtained as byproducts of other experiments (WIMP exp.) n But they don´t compete with helioscopes… SolarSolar AxionsAxions n Principle of detection (axion helioscope) [Sikivie, PRL 51 (87)] AXION PHOTON CONVERSION

axions

Transverse magnetic field (B) L

X ray X ray detector

COHERENCE 1 HelioscopesHelioscopes n Previous helioscopes: – First implementation at Brookhaven (just few hours of data) [Lazarus et at. PRL 69 (92)] – TOKYO Helioscope: 2.3 m long 4 T magnet

n Presently running: – CERN Axion Solar Telescope (CAST)

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 45 CERNCERN AxionAxion SolarSolar TelescopeTelescope (CAST)(CAST) n Decommissioned LHC test magnet (L=10m, B=9 T) n Moving platform ±8°V ±40°H (to allow up to 50 days / year of alignment) n 4 magnet bores to look for X rays n 3 X rays detector prototypes being used. n X ray Focusing System to increase signal/noise ratio.

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 46 Platform & magnet CAST Picture taken on mar 2002 First test platform movement with magnet

Magnet pointing up Magnet +8º pointing down -8º

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 47 Tracking system Looking at sunrise Twice a year (September and March) we CAST can film the Sun through the window

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 48 Tracking system Processed filming material Filming the Sun CAST

MARCH’03

SEPTEMBER’03

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 49 Igor G. Irastorza, CERN / Zaragoza U. Seminar 19.12.03 Zaragoza University X-ray detectors CAST

TPC Micromegas

CCD with Telescope

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 50 Igor G. Irastorza, CEA Saclay / CERN / Zaragoza U. IDM2004, Edinburgh 6-11.09.04 CASTCAST experimentexperiment :: STATUSSTATUS ü2003 data taking üCAST running for about 6 months üData analyzed --> first result (accepted by Physical Review Letters) ü2004 data taking üImproved conditions on all detectors (shieldings,…), tracking system and magnet (more reliability, homogeneity of data taking) üFourth detector for HE axions üCAST running from May to November Calorimeter for HE axions from solar M1 transitions (and more)

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 51 Igor G. Irastorza, CEA Saclay / CERN / Zaragoza U. IDM2004, Edinburgh 6-11.09.04 CASTCAST sensitivitysensitivity

ü Subtracted spectrum à “expected“axion spectrum

/s 2 Solar axion spectrum for g ~ 6 x 10-10 GeV-1 (Tokyo Helioscope sensitivity)

c/keV/cm

CAST TPC Subtracted spectrum Comparison of sensitivities of CAST and Tokyo Helioscope

IMFP2005, Benasque, March Energy [keV] 2005 Igor G. Irastorza / CEA, Saclay 52 CASTCAST firstfirst results:results: 20032003 datadata

TPC 2003 data CCD 2003 data

MICROMEGAS 2003 data No signal over background in any of the three detectors

combined limit obtained (95%): -10 -10 gagg < 1.16 x 10 GeV

IMFP2005, Benasque, March 2005Igor G. Irastorza Igor G. Irastorza / CEA, Saclay3rd CAST Analysis Meeting - CERN 07.10.200353 CASTCAST firstfirst results:results: 20032003 datadata

Axion exclusion plot

-10 -1 gagg < 1.16 x 10 GeV

In the coherence region

•2003 result will be published soon (just accepted by PRL)

•More to come… •analysis of 2004 data ongoing •phase II with buffer gas

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 54 ““LaboratoryLaboratory”” axionsaxions n The existence of the axions (or axion-like particles) can manifest in the laboratory: – “Light shinning through wall”

axion photon

photon B B photon source detector WALL

– Other more “subtle” effects à PVLAS experiment…

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 55 PVLASPVLAS n PVLAS was not designed to look for axions, but to study the “vacuum magnetic birefringence“ n QED predicts that vacuum must show a (very small) birefringence when a magnetic field is applied n In particle physics language, polarized photons interact with the B field by means of this loop, provoking a phase out with respect perpendicular polarization (=ellipticity)

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 56 PVLASPVLAS positivepositive resultresult

PVLAS group is checking n Observed ellipticity signal the signal against all possible is (for 5.5 T): systematics since a few years – Dn = 3.4 × 10-18 n While QED prediction is – Dn = 1.21 × 10-22 n A factor > 104 higher !! n Other effects? – Systematics (the signal has survived all tests so far) – New physics? Speculations… axions?

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 57 PVLASPVLAS axionaxion (?)(?) n Axions could produce vacuum magnetic birefringence (ellipticity). virtual production of axions Ellipticity n But also another effect, dichroism.

Real production of axions Rotation of polarization - Dichroism

PVLAS also observe an effect of dichroism (with low statistics), which is NOT expected at all by QED.

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 58 PVLASPVLAS axion(?)axion(?) n In the standard scenario, PVLAS signal is not compatible with solar axion experiments (even just solar physics)

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 59 ConclusionsConclusions n Growing evidence for a “beyond-SM” Dark Matter candidate (axions and WIMPs are the favorites) n Big experimental effort is under way. Many different strategies/developments being explored. Maybe is time to face big projects/collaborations. n Exciting times for the field: suspicious signals both in WIMP and axion searches !!!

IMFP2005, Benasque, March 2005 Igor G. Irastorza / CEA, Saclay 60