Transcript

La Materia Oscura La Materia Oscura delldell’’Universo e i risultati Universo e i risultati delldell’’esperimento DAMAesperimento DAMA

R. Cerulli

INFN-LNGS

Gennaio 2007

Evidenze sperimentali sullEvidenze sperimentali sull’’esistenza esistenza della Materia Oscuradella Materia Oscura

Prima evidenza sperimentale dell’esistenza di Materia Oscura nell’Universo: misure delle velocità delle galassie che compongono l’ammasso COMA eseguite da Zwicky nel 1933.

Pochi anni più tardi nel 1936 Smith confermò l’esistenza di Materia Oscura studiando l’ammasso di galassie della Vergine.

Uno studio sistematico che accredita l’esistenza di Materia Oscura anche a livello di singole galassie è stato eseguito nel 1974 da due diversi gruppi, considerando molte galassie a spirale.

Queste osservazioni mostrarono che la sola componente visibile di materia non poteva dare conto delle velocità misurate e che la materia non luminosa era presente nell’ammasso in percentuale nettamente superiore rispetto alla materia visibile.

velocità di rotazione degli oggetti astrofisici di una galassia a spirale ad una distanza R dal centro della galassia.

Vediamo qui in particolare come è stato possibile evidenziare la presenza di Materia Oscura nelle galassie a spirale:

• Nel caso di sola materia luminosa, gli oggetti molto distanti dal centro della galassia, al di fuori del disco luminoso, dovrebbero avere una velocità che decresce all’aumentare di R (~1/√R).

• Le misure sperimentali mostrano, invece, che tali oggetti hanno velocità quasi costante per grandi valori di R. Tale risultato indica che deve esistere un’altra componente di materia, non visibile, detta alone oscuro.

∫=V

dVrM ρ)(In particular, spherical symmetry; mass inside a sphere:

rrGMv

rvm

rmrGM )( ;)( 2

2

2 =⇒=

rv 1

∝• Solar system or solar-system-like:

2

1 ;)(r

ρrrM ∝⇒∝• Galaxy: v about flat:

rrdrrrrrM

rrr

r 2000

22

20

02

20

0 4'''

4)( ;)( πρρπρρ ==⇒= ∫3

34 rV π=

.44)( 200

200 constrG

rrrG

rrGMv ==== ρππρ

In fact:

Altre evidenze sullAltre evidenze sull’’esistenza della esistenza della Materia OscuraMateria Oscura

Studio del moto della Grande Nube di Magellano intorno all nostra Galassia

Studio dei raggi-X emessi dai gas che circondano le galassie ellittiche

Studio della distribuzione della velocità del plasma caldo intergalattico negli ammassi

COMA Cluster

Anche la nostra Galassia (la Via Lattea) contiene al suo interno un alone oscuro che la pervade

La Via Lattea

Nella collisione tra due ammassi le galassie si comportano come un gas di particelle non interagenti mentre le nubi di plasma all’interno dell’ammasso - che si comportano come un fluido ed emettono raggi X – sono fortemente interagenti e sono sottoposte alla “pressione di ariete”

Dopo la collisione le galassie precedono il plasma rallentato dalla “pressione di ariete” e le due componenti si trovano in due regioni ben separate

Una recente prova dellUna recente prova dell’’esistenza di esistenza di Materia OscuraMateria Oscura

Il profilo del potenziale gravitazionale ottenuto Il profilo del potenziale gravitazionale ottenuto studiando il lensing gravitazionale studiando il lensing gravitazionale (contorno verde)(contorno verde) èè in in accordo con la distribuzione spaziale delle galassie e accordo con la distribuzione spaziale delle galassie e non con la distribuzione del plasmanon con la distribuzione del plasma

Questo si spiega ammettendo che la maggior parte Questo si spiega ammettendo che la maggior parte della materia presente nel sistema della materia presente nel sistema èè non luminosanon luminosa

Teorie della gravitTeorie della gravitàà modificata non sono in grado di dar modificata non sono in grado di dar conto delle osservazioniconto delle osservazioni

Collisione di due ammassi di galassie (1E0657-558 a z=0.296) avvenuta circa 100Myr fa

D. Clowe et al., astro-ph/0608407

Indicazioni dalla presenza di Materia Indicazioni dalla presenza di Materia Oscura dalla cosmologiaOscura dalla cosmologia

Le fondamenta del modello del Big Bang

La scoperta dell’espansione dell’Universo – E. Hubble (1929)

la distanza di alcune nebulose dimostrando che erano galassie esterne

le loro velocità di recessione

L’espansione dell’UniversoNel 1917 si pensava che l’Universo fosse statico e consistesse nella nostra Galassia e lo spazio vuoto che la circondava.

Negli anni venti, E. Hubble usando il nuovo telescopio da 2.5 m sul monte Wilson riuscì a misurare:

Le galassie si allontanano con una velocitàdi recessione proporzionale alla distanza

dHv 0=

H0=500 km/s/Mpc H0=71 km/s/Mpc

Galassia M31- Andromeda

La Via Lattea

Espansione generale dello spazio-tempo:Le galassie non si allontanano nello spazio ma è lo spazio stesso che si espande, trascinando con sèle galassieLe dimensioni fisiche delle galassie non cambiano→la gravità le “isola” dall’espansione

Effetto osservabile su scala intergalattica: la stella più vicina al Sole (Proxima Centauri), 4.22 anni-luce, si allontana da noi per il solo effetto dell’espansione con una velocità di soltanto 10 cm/s !!

Espansione priva di un centro:Un osservatore da una qualsiasi galassia vede la stessa espansione →l’unica legge di espansione compatibile con il Principio Cosmologico

Le fondamenta del modello del Big Bang

La scoperta dell’espansione dell’Universo – E. Hubble (1929)

Le abbondanze degli elementi leggeri: H, He, Li – G. Gamow (1948)

Le abbondanze degli elementi (i primi 3 minuti)

QUARKS Barioniprotoni, neutroni

Leptonielettroni, neutrini

Bariogenesi

Interazioni menofrequenti

1 neutrone ogni 7 protoni,

fotoni

1 secondo

Formazione dei nuclei atomici

H, He

100 secondi

non avverrà MAI PIU’nella storia dell’Universo

7

1

Gamow:La radiazione del Big Bang sopravvive ma a causa dell’espansione si raffredda

Previsione di Gamow:

Radiazione “fossile” = 5 K -268 °Cdue neutroni formano 1 nucleo di He

25% He 75% H

Le fondamenta del modello del Big Bang

La scoperta dell’espansione dell’Universo – E. Hubble (1929)

La scoperta della radiazione di fondo cosmico (CMB) – Penzias e Wilson (1965)

Le abbondanze degli elementi leggeri: H, He, Li – G. Gamow (1948)

Radiazione Fossile del Big BangViene scoperta da Penzias e Wilson (1965)

Temperatura della radiazione misurata: 3 K(banda delle micro-onde)

Riempie uniformemente il cielo!nessuna sorgente astrofisica sarebbe in grado di produrre una radiazione così uniforme!

L’immagine più antica dell’Universo 380’000 anni dopo il Big Bang la radiazione

si “libera” dalla materia ed inizia a propagarsi

La radiazione fossile mantiene “memoria”dello stato dell’Universo quando aveva lo

0.003% della sua età attualeSpettro della Radiazione

... e il lato oscuro dell’Universo?

Il miglioramento delle tecniche sperimentali ha permesso di ottenere informazioni anche sul lato oscuro dell’Universo

La radiazione cosmica di fondo ha permesso di studiare il valore della densità totale dell’Universo (Ω= ρ/ρ0) e i diversi contributi ad essa. SN 1987A vista dal telescopio Hubble

La verifica della legge di Hubble su scala sempre piùgrande permette di avere informazioni sull’espansione accelerata → costante cosmologica ed energia oscura

La nucleosintesi primordiale ha permesso di studiare quanti barioni ci sono oggi nell’Universo → necessità di materia oscura

Fluttuazione nella radiazione fossile: gli embrioni delle galassie

Le fluttuazioni di temperatura sono la traccia di fluttuazioni di densità della materia: gli embrioni delle galassie che cresceranno attraverso l’amplificazione gravitazionale

WMAP

(T2-T1)/T1=3×10-5

Nel 1992, COBE rivelò per primo piccole fluttuazioni ditemperatura (indicate da variazioni di colore)

Immagine a tutto cielodell’Universo 380000 annidopo il Big Bang.

WMAP nel 2003 ha messo a fuocol’immagine data da COBE

WMAP

Se Ω =1, è prevista la presenza di un picco a l ∼ 200

Composizione dell’Universo (barioni)Parametro di densità: Ω = densità/densità critica 6 atomi di H/m3

Ω = 1Barioni (cioè protoni, nuclei e atomi):

ΩB = 4%

La teoria cosmologica del Big Bang prevede, negli scenari teorici più accreditati, Ω=1. Verifica dalle misure sulla anisotropia di CMB

Considerando:a) la presente abbondanza di nuclei leggerib) la densità dei fotoni CMB

E’ necessaria Materia Oscura Non Barionica:- particelle relitte dall’Universo primordiale- relativistiche (Hot DM) o non-relativistiche (Cold DM)

al tempo del disaccoppiamento- Hot DM: neutrinos- Cold DM: WIMPs, axions, axion-like, ...

Composizione dell’Universo (energia oscura)

Negli ultimi 10 anni, studio della legge di Hubble su scala sempre più grande, attraverso l’utilizzo di “candele standard”: supernovae Ia (SN Ia).

informazioni sull’espansione accelerata → costante cosmologica ed energia oscura

Universo dominato dalla materia oscuraUniverso dominato da Λ

27.0 ;73.0 ≈Ω≈ΩΛ M

energia del vuoto caratterizzata da una pressione negativa

Contributo della materia (oscura e non)

PrimordialNucleosynthesis

∼ 90% of the matter in the Universe is non baryonicA large part of the Universe is in form of non baryonic Cold Dark Matter particles

73.0≈ΩΛ

““ConcordanceConcordance modelmodel””

WMAP

Supernovae IA

27.0

Ω = ΩΛ + ΩM =1.02±0.02

≈ΩMThe Universe is flat

Observations on: • light nuclei abundance

• microlensings• visible light.

ΩCDM ∼ 23%,ΩHDM,ν < 1 %ΩCDM ∼ 23%,ΩHDM,ν < 1 %

The baryons give “too small”contribution

Ωb ∼ 4% Ωb ∼ 4% Non baryonic Cold Dark

Matter is dominant

Structure formationin the Universe

Ω = densità/densità critica

6 atomi di H/m3

heavy exotic canditates, as “4th family atoms”, ...

self-interacting dark matter

Kaluza-Klein particles (LKK)

mirror dark matter

even a suitable particle not yet foreseen by theories

SUSY (R-parity conserved → LSP is stable)

neutralino or sneutrino

the sneutrino in the Smith and Weiner scenario &

a heavy ν of the 4-th family

axion-like (light pseudoscalar and scalar candidates)Heavy candidates:

• In thermal equilibrium in the early stage of Universe• Non relativistic at decoupling time <σann

.v> ~ 10-26/ΩWIMPh2 cm3s-1 → σordinary matter ~ σweak• Expected flux: Φ ~ 107 . (GeV/mW) cm-2 s-1 (0.2<ρhalo<1.7 GeV cm-3)• Form a dissipationless gas trapped in the gravitational field of the Galaxy (v ~10-3c)• neutral • stable (or with half life ~ age of Universe) • massive• weakly interacting

Relic CDM particles from primordial UniverseRelic CDM particles from primordial UniverseLight candidates: axion, axion-like produced at rest(no positive results from direct searches for relic axions with resonant cavity)

DM particles may accumulate in Sun/Earth, in galactic halo

↓annihilate

↓high energy neutrinos, g’s, anti-p and e+

↓Search for an excess over the (largely

unknown) background

detector

DMp

EARTHµ

νµ

SUN

DMp

DMp

DMp

DMp

DMp-antiDMp

Indirect detectionIndirect detection

νµ signature• Best signature from νµ

producing up-ward going µ

• Underground, underwater, underice detectors

γ signature• Search for quasi-

monoenergetic γ’s in cosmic rays

• Space detectors

antimatter signature

• Search for antimatter excess in cosmic rays

• Space detectors

Similar searches can offer only results, which strongly depend on the background modeling and on the

astrophysical, particle and nuclear Physics assumptions

La rivelazione diretta delle particelle di La rivelazione diretta delle particelle di Materia OscuraMateria Oscura

• Questa tecnica si basa (principalmente) sullo studio dell’interazione elastica delle particelle di DM con i nuclei che costituiscono il rivelatore utilizzato.

• A seguito di una interazione elastica di una particella con un nucleo, questo rincula.

• L’energia di rinculo del nucleo è, quindi, la grandezzamisurata.

• Si possono utilizzare rivelatori a scintillazione (NaI(Tl), LXe,CaF2(Eu),etc.), a ionizzazione (Ge, Si), Bolometri (TeO2, Ge)

DMp Nucleo

DMp

Energia di rinculo

Diffusione su nuclei-bersaglio

Conversione in radiazione elettromagnetica

• A seguito della conversione della particellanell’interazione con il nucleo, vengono prodotti γ, raggi-X o e- con energia circa uguale alla sua massa

e-

X-ray

NOTA: i segnali prodotti da questi candidati sono perduti in esperimenti basati sulle procedure di reiezione del fondo elettromagnetico

Diffusione elastica sul nucleo con eccitazione di elettroni legati

• Si misura l’energia di rinculo del nucleo e la radiazione e.m. prodotta

Main recipes for the Dark Matter particle direct detection

- Background at LNGS:muons → 0.6 µ/(m2h)neutrons → 1.08·10-6 n/(cm2s) thermal

1.98·10-6 n/(cm2s) epithermal0.09·10-6 n/(cm2s) fast (>2.5 MeV)

Radon in the hall → ≈30 Bq/m3

- Internal Background:selected materials (Ge, NaI, AAS, MS, ...)

ShieldingPassive shield: Lead (Boliden [< 30 Bq/kg from 210Pb], LC2 [<0.3 Bq/kg from 210Pb], lead from old roman galena), OFHC Copper, Neutron shield (low A materials, n-absorber foils)Active shield: Low radio-activity NaI(Tl) surrounding the detectors

• Underground site• Low bckg hard shields

against γ’s, neutrons• Lowering bckg: selection of

materials, purifications, growing techniques, ...

• Rn removal systems

Background sources

Example of background reduction

during many years of work

Reduction from the

underground site

Example of the effect of a passive shield

• Experimental vs Expected spectra (with or without bckg rejection )

+

by model: σp

MW

σ nucl

eus

Excluded atgiven C.L.

Exclusion plot

An exclusion plot not an absolutelimit. When different target nuclei, no absolute comparison possible.

• No discovery potentiality

• Uncertainties in the exclusion plots and in their comparison

• Warning: limitations in the recoil/background discrimination (always not event by event): PSD (τ of the pulse depends on the particle) in scintillators(NaI(Tl), LXe), Heat/Ionization (Ge), Heat/Scintillation (CaF2(Eu), CaWO4).

several assumptions and modeling required

experimental and theoretical uncertainties generally not included in calculations

The The ““traditionaltraditional”” approachapproach

To have a potentiality of discovery a model independent signature is needed !

A model independent signature is needed

Directionality Correlation of nuclear recoil track with

Earth's galactic motion due to the distribution of Dark

Matter particles velocities very hard to realize

Nuclear-inelastic scatteringDetection of γ’s emitted by

excited nucleus after a nuclear-inelastic scattering.

very large exposure and very low counting rates hard to realize

Diurnal modulation Daily variation ofthe interaction rate due to different Earth depth crossed by the Dark Matter particles

only for high σ

Annual modulation Annual variation of the interaction rate due to Earth motion around the Sun.

at present the only feasible one

The annual modulation: a model independent signature for the The annual modulation: a model independent signature for the investigation of Dark Matter particles component in the galacticinvestigation of Dark Matter particles component in the galactic halohalo

With the present technology, the annual modulation is the main mWith the present technology, the annual modulation is the main model independent signature for the DM odel independent signature for the DM signal. Although the modulation effect is expected to be relativsignal. Although the modulation effect is expected to be relatively smallely small a suitable a suitable largelarge--mass, lowmass, low--radioactiveradioactive setset--up with an efficient control of the running conditions would poiup with an efficient control of the running conditions would point out its presencent out its presence..

December30 km/s

~ 232 km/s60°

June30 km/s

Drukier, Freese, Spergel PRD86Freese et al. PRD88 • vsun ~ 232 km/s (Sun velocity in the halo)

• vorb = 30 km/s (Earth velocity around the Sun)• γ = π/3• ω = 2π/T T = 1 year• t0 = 2nd June (when v⊕ is maximum)

Expected rate in given energy bin changes because the annual motion of the Earth around the Sun moving in the Galaxy

v⊕(t) = vsun + vorb cosγcos[ω(t-t0)]

)](cos[)]([ 0,,0 ttSSdEdEdRtS km

EkR

Rk

k

−+≅= ∫∆

ωη

Requirements of the annual modulationRequirements of the annual modulation

1)1) Modulated rate according cosineModulated rate according cosine

2)2) In a definite low energy rangeIn a definite low energy range

3)3) With a proper period (1 year)With a proper period (1 year)

4)4) With proper phase (about 2 June)With proper phase (about 2 June)

5)5) For single hit events in a multiFor single hit events in a multi--detector setdetector set--upup

6)6) With modulation amplitude in the region of maximal sensitivity With modulation amplitude in the region of maximal sensitivity must be <7% for usually adopted halo distributions, but it can must be <7% for usually adopted halo distributions, but it can be larger in case of some possible scenarios

To mimic this signature, spurious To mimic this signature, spurious effects and side reactions must effects and side reactions must not only not only -- obviously obviously -- be able to be able to account for the whole observed account for the whole observed modulation amplitude, but also modulation amplitude, but also to satisfy contemporaneously all to satisfy contemporaneously all

the requirementsthe requirements

be larger in case of some possible scenarios

DAMA/R&DDAMA/LXe low bckg DAMA/Ge

for sampling meas.

DAMA/NaI

DAMA/LIBRA

http://people.roma2.infn.it/dama

Roma2,Roma1,LNGS,IHEP/Beijing

DAMA/LXe: results on rare processes DAMA/LXe: results on rare processes Dark Matter Investigation• Limits on recoils investigating the DMp-129Xe

elastic scattering by means of PSD • Limits on DMp-129Xe inelastic scattering• Neutron calibration• 129Xe vs 136Xe by using PSD → SD vs SI signals to

increase the sensitivity on the SD component

PLB436(1998)379PLB387(1996)222, NJP2(2000)15.1PLB436(1998)379, EPJdirectC11(2001)1

foreseen/in progress

Other rare processes:• Electron decay into invisible channels• Nuclear level excitation of 129Xe during CNC processes• N, NN decay into invisible channels in 129Xe

• Electron decay: e- → νeγ• 2β decay in 134Xe

• Improved results on 2β in 134Xe,136Xe• CNC decay 136Xe → 136Cs• N, NN, NNN decay into invisible channels in 136Xe

Astrop.Phys5(1996)217

PLB465(1999)315

PLB493(2000)12

PRD61(2000)117301

PLB527(2002)182

PLB546(2002)23

Beyond the Desert (2003) 365

EPJA27 s01 (2006) 35

NIMA482(2002)728

• 2β decay in 136Ce and in 142Ce• 2EC2ν 40Ca decay• 2β decay in 46Ca and in 40Ca• 2β+ decay in 106Cd• 2β and β decay in 48Ca• 2EC2ν in 136Ce, in 138Ce

and α decay in 142Ce• 2β+ 0ν and EC β+ 0ν decay in 130Ba• Cluster decay in LaCl3(Ce)

• Particle Dark Matter search with CaF2(Eu)

DAMA/R&D setDAMA/R&D set--up: results on rare processesup: results on rare processesNPB563(1999)97, Astrop.Phys.7(1997)73

Il Nuov.Cim.A110(1997)189

Astrop. Phys. 7(1999)73

NPB563(1999)97

Astrop.Phys.10(1999)115

NPA705(2002)29

NIMA498(2003)352

NIMA525(2004)535

NIMA555(2005)270

Il Nuovo Cim. A112 (1999) 545-575, EPJC18(2000)283, Riv. N. Cim. 26 n.1 (2003)1-73, IJMPD13(2004)2127

• Reduced standard contaminants (e.g. U/Th of order of ppt) by material selection and growth/handling protocols.

• PMTs: Each crystal coupled - through 10cm long tetrasil-B light guides acting as optical windows - to 2 low background EMI9265B53/FL (special development) 3” diameter PMTs working in coincidence.

• Detectors inside a sealed Cu box maintained in HP Nitrogen atmosphere in slight overpressure

•• data taking of each annual cycledata taking of each annual cycle starts from autumn/winter (when cosω(t-t0)≈0) toward summer (maximum expected).•• routine calibrationsroutine calibrations for energy scale determination, for acceptance windows efficiencies by means of radioactive sources

each ~ 10 days collecting typically ~105 evts/keV/detector + intrinsic calibration from 210Pb (~ 7 days periods) + periodical Compton calibrations, etc.

•• continuous oncontinuous on--line monitoring of all the running parametersline monitoring of all the running parameters with automatic alarm to operator if any out of allowed range.

Main procedures of the DAMA data taking for the DMp annual modulMain procedures of the DAMA data taking for the DMp annual modulation signatureation signature

•Very low radioactive shields: 10 cm of Cu, 15 cm of Pb + shield from neutrons: Cd foils + polyethylene/paraffin+ ~ 1 m concrete moderator largely surrounding the set-up

• Installation sealed: A plexiglas box encloses the whole shield and is also maintained in HP Nitrogen atmosphere in slight overpressure. Walls, floor, etc. of inner installation sealed by Supronyl (2×10-11 cm2/s permeability).Three levels of sealing.

• Installation in air conditioning + huge heat capacity of shield

•Calibration using the upper glove-box (equipped with compensation chamber) in HP Nitrogen atmosphere in slight overpressure calibration → in the same running conditions as the production runs.

•Energy and threshold: Each PMT works at single photoelectron level. Energy threshold: 2 keV (from X-ray and Compton electron calibrations in the keV range and from the features of the noise rejection and efficiencies). Data collected from low energy up to MeV region, despite the hardware optimization was done for the low energy

•Pulse shape recorded over 3250 ns by Transient Digitizers.

•Monitoring and alarm system continuously operating by self-controlled computer processes.

+ electronics and DAQ fully renewed in summer 2000

total exposure collected in 7 annual cyclestotal exposure collected in 7 annual cycles

Results on DM particles:

107731 kg×d107731 kg×d

DAMA/NaI(Tl)~100 kgDAMA/NaI(Tl)~100 kgResults on rare processes:

•• PSDPSD PLB389(1996)757•• Investigation on diurnal effectInvestigation on diurnal effect

N.Cim.A112(1999)1541•• Exotic Dark Matter search Exotic Dark Matter search PRL83(1999)4918•• Annual ModulationAnnual Modulation SignatureSignature

PLB424(1998)195, PLB450(1999)448, PRD61(1999)023512, PLB480(2000)23,EPJ C18(2000)283, PLB509(2001)197, EPJ C23 (2002)61, PRD66(2002)043503, Riv.N.Cim.26 n.1 (2003)1-73, IJMPD13(2004)2127, IJMPA21(2006)1445),EPJC47(2006)263

• Possible Pauli exclusion principle violation• CNC processes• Electron stability and non-paulian transitions in

Iodine atoms (by L-shell) • Search for solar axions• Exotic Matter search• Search for superdense nuclear matter• Search for heavy clusters decays

PLB408(1997)439PRC60(1999)065501

PLB460(1999)235PLB515(2001)6EPJdirect C14(2002)1EPJA23(2005)7 EPJA24(2005)51

Performances: N.Cim.A112(1999)545-575, EPJC18(2000)283, Riv.N.Cim.26 n. 1(2003)1-73, IJMPD13(2004)2127

data taking completed on July 2002data taking completed on July 2002

from the fit with all the parameters free:from the fit with all the parameters free:A = (0.0200 A = (0.0200 ±± 0.00320.0032) ) cpd/kg/keVcpd/kg/keVtt00 = (140 = (140 ±± 22) d 22) d T = (1.00 T = (1.00 ±± 0.01) y0.01) y

model independent evidence of a particle Dark Matter component in the galactic halo at 6.3σ C.L.

model independent evidence of a particle Dark Matter model independent evidence of a particle Dark Matter component in the galactic halo at 6.3component in the galactic halo at 6.3σσ C.L.C.L.

Power Power spectrumspectrum

Principal mode → 2.737 · 10-3 d-1 ≈ 1 y-1

P(A=0) = 7P(A=0) = 7⋅⋅1010--44

Solid line: tSolid line: t00 = 152.5 days, T = 1.00= 152.5 days, T = 1.00 yearsyearsfrom the fit: from the fit:

A = (0.0192 A = (0.0192 ±± 0.00310.0031) ) cpd/kg/keVcpd/kg/keV

All the peculiarities of the signature satisfiedAll the peculiarities of the All the peculiarities of the signature satisfiedsignature satisfied No systematics or side reaction able to account

for the measured modulation amplitude and to satisfy all the peculiarities of the signature

No No systematicssystematics or side reaction able to account or side reaction able to account for the measured modulation amplitude and to for the measured modulation amplitude and to satisfy all the peculiarities of the signaturesatisfy all the peculiarities of the signature

2-6 keV

6-14 keV

Experimental residual rate of the single hit events in 2-6 keV over 7 annual cycles

Acos[ω(t-t0)]

Final model independent result by DAMA/NaIFinal model independent result by DAMA/NaI

2-6 keV

experimental residual rate of the multiple hit events (DAMA/NaI-6 and 7) in the 2-6 keV energy interval: A = -(3.9±7.9) ·10-4 cpd/kg/keV

experimental residual rate of the single hit events (DAMA/NaI-1 to 7) in the 2-6 keV energy interval:A = (0.0195±0.0031) cpd/kg/keV

Multiple hits events = Dark Matter particle “switched off”

7 annual cycles: total exposure ~ 1.1 x 105 kg×dRiv. N. Cim. 26 n. 1 (2003) 1-73, IJMPD 13 (2004) 2127

Time (day)

What we can also learn from the multiple/single hit rates. A toy model

2singlemult 4 rNRR TT

πσ

⋅=

The 8 NaI(Tl) detectors in (anti-)coincidence have 3.1×1026 nuclei of Na and 3.1×1026 nuclei of Iodine. N= 3.1×1026

( )INaIINaNaTT NNNN σσσσσ +⋅=+=

( )2singlemult 4 med

INa

rNRR

⋅+⋅

⋅≈π

σσ rmed ∼ 10-15 cm

;cpd/kg/keV 10cpd/kg/keV 10)84( 34 −− <⋅±−≈multA

;cpd/kg/keV 102 2single

−⋅≈A

2

single

105 −⋅<AAmult

( )2

single 4 med

INamult

rN

AA

⋅+⋅

≈π

σσ

barn 2.0<+ INa σσ

Therefore, the ratio of the modulation amplitudes is:

From the experimental data:

Hence:

In conclusion, the particle (A) responsible of the modulation in the single-hit rate and not in the multiple-hit rate must have:

Since for fast neutrons the sum of the two cross sections (weighted by 1/E, ENDF/B-VI) is about 4 barns:

A A’

It

What about the nuclear cross sections of the particle(A) responsible of the modulation in the single-hit rate and not in the multiple-hit rate?

(A) cannot be a fast neutron

Pressure

Temperature

Radon outside the shield

Nitrogen Flux hardware ratean example:DAMA/NaI-6

Running conditions stable at level < 1%

Distribution of some parameters

All the measured amplitudes well compatible with zero

+ none can account for the observed effect

outside the shield

(to mimic such signature, spurious effects and side reactions must not only be able to

account for the whole observed modulation amplitude, but also simultaneously satisfy all

the 6 requirements)

Running conditionsRunning conditions

[for details and for the other annual cycles see for example: PLB424(1998)195, PLB450(1999)448, PLB480(2000)23, RNC26(2003)1-73, EPJC18(2000)283, IJMPD13(2004)2127]

Modulation amplitudes obtained by fitting the time behaviours of main running parameters, acquired with the production data, when including a modulation term as in the Dark Matter particles case.

Can a hypothetical background modulation Can a hypothetical background modulation account for the observed effect?account for the observed effect?

Integral rate at higher energy (above 90 keV), R90

Energy regions closer to that where the effect is observed e.g.:Mod. Ampl. (6-10 keV): -(0.0076 ± 0.0065), (0.0012 ± 0.0059) and (0.0035 ± 0.0058) cpd/kg/keV for DAMA/NaI-5, DAMA/NaI-6 and DAMA/NaI-7; → they can be considered statistically consistent with zeroIn the same energy region where the effect is observed:no modulation of the multiple-hits events (see elsewhere)

• Fitting the behaviour with time, adding a term modulated according period and phase expected for Dark Matter particles:

→consistent with zero + if a modulation present in the whole energy spectrum at the level found in the lowest energy region → R90 ∼ tens cpd/kg → ∼ 100 σ far away

No modulation in the background:these results also account for the bckg component due to neutrons

No modulation in the background:these results also account for the bckg component due to neutrons

• R90 percentage variations with respect to their mean values for single crystal in the DAMA/NaI-5,6,7 running periods

Period Mod. Ampl.DAMA/NaI-5 (0.09±0.32) cpd/kgDAMA/NaI-6 (0.06±0.33) cpd/kgDAMA/NaI-7 -(0.03±0.32) cpd/kg

→ cumulative gaussian behaviour with σ ≈ 0.9%, fully accounted by statistical considerations

(see Riv. N. Cim. 26 n. 1 (2003) 1-73, IJMPD13(2004)2127 and references therein)

Summary of the results obtained in the investigations of Summary of the results obtained in the investigations of possible systematics or side reactionspossible systematics or side reactions

Source Main comment Cautious upperlimit (90%C.L.)

RADON Sealed Cu box in HP Nitrogen atmosphere,etc <0.2% Smobs

TEMPERATURE Installation is air conditioned+ <0.5% Smobs

detectors in Cu housings directly in contact with multi-ton shield→ huge heat capacity+ T continuously recorded

NOISE Effective noise rejection <1% Smobs

ENERGY SCALE Periodical calibrations + continuous monitoring <1% Smobs

of 210Pb peakEFFICIENCIES Regularly measured by dedicated calibrations <1% Sm

obs

BACKGROUND No modulation observed above 6 keV + this limit <0.5% Smobs

includes possible effect of thermal and fast neutrons+ no modulation observed in the multiple-hits events in 2-6 keV region

SIDE REACTIONS Muon flux variation measured by MACRO <0.3% Smobs

+ even if larger they cannot satisfy all the requirements of annual modulation signature

Thus, they can not mimic the observed annual

modulation effect

No other experiment whose result can be directly compared in model independent way is available so far

Presence of modulation for 7 annual cycles at ~6.3σC.L. with the proper distinctive features of the

signature; all the features satisfied by the data over 7 independent experiments of 1 year each one

Absence of known sources of possible systematics and side processes able to

quantitatively account for the observed effect and to contemporaneously satisfy the many

peculiarities of the signature

To investigate the nature and coupling with ordinary matter of the possible DM candidate(s), effective energy and time correlation analysis of the events has to be performed within given model frameworks

Summary of the DAMA/NaI Model Independent result

astrophysical models: ρDM, velocity distribution and its parameters

nuclear and particle Physics models

experimental parameters

THUSuncertainties on models

and comparisons

e.g. for WIMP class particles: SI, SD, mixed SI&SD, preferred inelastic, scaling laws on cross sections, form factors and related parameters, spin factors, halo models, etc.

+ different scenarios+ multi-component?

+

Corollary quests for candidate(s)

First case: the case of DM particle scatterings on target-nuclei.The recoil energy is the detected quantity

DM particle-nucleus elastic scattering SI+SD differential cross sections:gp,n(ap,n) effective DM particle-nucleon couplings

<Sp,n> nucleon spin in the nucleus

F2(ER) nuclear form factors

mWp reduced DM particle-nucleon mass

dσdER

(v,ER) = dσdER

⎝ ⎜ ⎞

⎠ ⎟

SI

+ dσdER

⎝ ⎜ ⎞

⎠ ⎟

SD

=

2GF2mN

πv2 Zgp + (A− Z)gn[ ]2FSI

2 (ER) + 8 J +1J

ap Sp + an Sn[ ]2FSD

2 (ER )⎧ ⎨ ⎩ ⎫ ⎬ ⎭

Differential energy distribution depends on the assumed scaling laws, nuclear form factors, spin factors, free parameters (→ kind of coupling, mixed SI&SD, pure SI, pure SD, pure SD through Z0 exchange, pure SD with dominant coupling on proton, pure SD with dominant coupling on neutron, preferred inelastic, ...), on the assumed astrophysical model (halo model, presence of non-thermalized components, particle velocity distribution, particle density in the halo, ...) and on instrumental quantities (quenching factors, energy resolution, efficiency, ...)

Note: not universal description. Scaling laws assumed to define point-like cross sections from nuclear ones. Four free parameters: mW, σSI, σSD , tgθ =

an

ap

Preferred inelastic DM particle-nucleus scattering: χ-+N→ χ++NSm/S0 enhanced with respect to the elastic scattering case

• DM particle candidate suggested by D. Smith and N. Weiner (PRD64(2001)043502)

• Two mass states χ+ , χ- with δ mass splitting• Kinematical constraint for the inelastic scattering of

χ- on a nucleus with mass mN becomes increasingly severe for low mN 1

2µv2 ≥ δ ⇔ v ≥ vthr =

2δµ

Three free parameters: mW, σp, δ

Ex. mW =100 GeVmN µ70 41

130 57

Spin Independent

2( ) /5nqre−

2 21 2( ) ( )(1 )n nqr qrAe A eα α− −+ −

Helm

charge spherical distribution

from Ressell et al.

from Helm

2 21 2( ) ( )(1 )n nqr qrAe A eα α− −+ −

Smith et al.,Astrop.Phys.6(1996) 87

2( ) /5nqre−

“thin shell”distribution

Spin Dependent

Examples of different Form Examples of different Form Factor for Factor for 127127I available I available in literaturein literature

• Take into account the structure of target nuclei

• In SD form factor: no decoupling between nuclear and Dark Matter particles degrees of freedom; dependence on nuclear potential.

Similar situation for all the target nuclei considered

in the field

The Spin FactorThe Spin FactorSpin Factors for some target-nuclei calculated in simple different models

Spin factor = Λ2J(J+1)/ax2

(ax= an or ap depending on the unpaired nucleon)

Spin Factors calculated on the basis of Ressell et al. for some of the possible θvalues considering some target nuclei and two different nuclear potentials

Spin factor = Λ2J(J+1)/a2

Large differences in the measured counting rate can be expected:• when using target nuclei sensitive to the SD component of the interaction (such as e.g. 23Na and 127I) with the respect

to those largely insensitive to such a coupling (such as e.g. natGe, natSi, natAr, natCa, natW, natO);• when using different target nuclei although all – in principle – sensitive to such a coupling, depending on the

unpaired nucleon (compare e.g. odd spin isotopes of Xe, Te, Ge, Si, W with the 23Na and 127I cases).

tgθ =an

ap

(0≤θ<π)

Astrop. Phys.3(1995)361

Quenching factors, q, measured by neutron sources or by neutron beams for some detectors and nuclei

assumed 1 (but 0.91 ±0.03 in astro-ph/0607502 )

• differences are often present in different experimental determinations of q for the same nuclei in the same kind of detector

• e.g. in doped scintillators q depends on dopant and on the impurities/trace contaminants; in LXe e.g.on trace impurities, on initial UHV, on presence of degassing/releasing materials in the Xe, on thermodynamical conditions, on possibly applied electric field, etc.

• Some time increases at low energy in scintillators (dL/dx)

recoil/electron response ratio measured with a neutron source or at a neutron generator

Ex. of different q determinations for Ge

Quenching factorQuenching factor

Consistent Halo ModelsConsistent Halo Models• Isothermal sphere ⇒ very simple but unphysical halo model; generally not considered• Several approaches different from the isothermal sphere model: Vergados PR83(1998)3597,

PRD62(2000)023519; Belli et al. PRD61(2000)023512; PRD66(2002)043503; Ullio & KamionkowskiJHEP03(2001)049; Green PRD63(2001) 043005, Vergados & Owen astroph/0203293, etc.

Models accounted in the following(Riv. N. Cim. 26 n.1 (2003)1-73 and previously in PRD66(2002)043503 )

10 )50220( −⋅±= skmv

⊕⊕ ⋅≤≤⋅ MMM vis1010 106101

00 2.1)100(8.0 vkpcrvv rot ⋅≤=≤⋅

• Needed quantities

→ DM local density ρ0 = ρDM (R0 = 8.5 kpc) → local velocity v0 = vrot (R0 = 8.5kpc) → velocity distribution ( )f vr

• Allowed ranges of ρ0 (GeV/cm3) have been evaluated for v0=170,220,270 km/s, for each considered halo density profile and taking into account the astrophysical constraints:

NOT YET EXHAUSTIVE AT ALL

Halo modelingHalo modeling• Needed quantities for Dark Matter direct searches:

→ DM local density ρ0 = ρDM (R0 = 8.5 kpc) → local velocity v0 = vrot (R0 = 8.5kpc) → velocity distribution ( )f vr

Isothermal sphere: the most widely used (but not correct) model

density profile: gravitational potential:

→ Maxwellian velocity distribution

2( )DM r rρ −∝ 20 log( )rΨ ∝

2

0 21r

vv

φβ = −Spherical ρDM with non-isotropic velocity dispersion →

Axisymmetric ρDM → q flatness

2 22 20

0 2( , ) log2 cv zr z R r

q⎛ ⎞

Ψ = − + +⎜ ⎟⎝ ⎠

Triaxial ρDM → p,q,δ2 2 2

200 2 2( , , ) log

2v y zx y z x

p q⎛ ⎞

Ψ = − + +⎜ ⎟⎝ ⎠

δ = free parameter → in spherical limit (p=q=1) quantifies the anisotropy of the velocity dispersion tensor

2

2

22r

vv

φ δ+=

2 2 20

2 2 2

3( )4 ( )

cDM

c

v R rrG R r

ρπ

+=

+

22 20

0 ( ) log( )2 cvr R rΨ = − +

22 2

2 2( )( )rot c

c

rv r vR r

=+

2 2

2 2 ( 4) / 2

3 (1 )( )4 ( )

a c cDM

c

R R rrG R r

β

β

β βρπ +

Ψ + −=

+ 0 2 2 / 2( ) , ( 0)( )

a c

c

RrR r

β

β βΨΨ = ≠

+

22

2 2 ( 2) / 2( )( )

a crot

c

R rv rR r

β

β

β+

Ψ=

+

( ) /

0 00

1 ( / )( )1 ( / )DM

R R arr r a

β γ αγ α

αρ ρ−

⎡ ⎤+⎛ ⎞= ⎜ ⎟ ⎢ ⎥+⎝ ⎠ ⎣ ⎦

Evans’logarithmic

Evans’power-law

Spherical ρDM, isotropic velocity dispersion

Others:

00 2.1)100(8.0 vkpcrvv rot ⋅≤=≤⋅⊕⊕ ⋅≤≤⋅ MMM vis1010 1061011

0 )50220( −⋅±= skmvConstraining the models

DM particle with elastic SI&SD interactions(Na and I are fully sensitive to SD interaction, on the contrary of e.g. Ge and Si) Examples of slices of the allowed volume in the space (ξσSI, ξσSD, mW, θ) for some of the possible θ (tgθ =an/ap with 0≤θ<π) and mW

Few examples of corollary quests for the WIMP class(Riv. N.Cim. vol.26 n.1. (2003) 1-73, IJMPD13(2004)2127)

Region of interest for a neutralino in supersymmetric schemes where assumption on gaugino-mass unification at GUT is released and for “generic” DM particle

DM particle with dominant SI coupling

Regions above 200 GeV allowed for low v0, for every set of parameters’ values and for Evans’logarithmic C2 co-rotating halo models

volume allowed in the space (mW,ξσSD,θ); here example of a slicefor θ=π/4 (0≤θ<π)

not exhaustive+ differentscenarios?

DM particle with preferred inelastic interaction: W + N → W* + N (Sm/S0 enhanced): examples of slices of the allowed volume in the space (ξσp, mW,δ)[e.g. Ge disfavoured]

DM particle with dominant SD coupling

higher mass region allowed for low v0,

every set of parameters’ values

and the halo models: Evans’

logarithmic C1 and C2 co-rotating,

triaxial D2 and D4 non-rotating, Evans

power-law B3 in setA

Most of these allowed volumes/regions areunexplorable e.g. by Ge, Si,TeO2, Ar,

Xe, CaWO4 targets

Model dependent lower bound on neutralino mass as derived from LEP data in supersymmetricschemes based on GUT assumptions (DPP2003)

An example of the effect induced by a nonAn example of the effect induced by a non--zero zero SD component on the allowed SI regionsSD component on the allowed SI regions

• Example obtained considering Evans’ logarithmic axisymmetric C2 halo model with v0 = 170 km/s, ρ0 max at a given set of parameters

• The different regions refer to different SD contributions with θ=0

a) σSD = 0 pb; b) σSD = 0.02 pb;c) σSD = 0.04 pb; d) σSD = 0.05 pb;e) σSD = 0.06 pb; f) σSD = 0.08 pb;

• There is no meaning in bare comparison between regions allowed in experiments sensitive to SD coupling and exclusion plots achieved by experiments that are not.

• The same is when comparing regions allowed by experiments whose target-nuclei have unpaired proton with exclusion plots quoted by experiments using target-nuclei with unpaired neutron where θ ≈ 0 or θ ≈ π.

A small SD contribution ⇒drastically moves the allowed region in the plane (mW, ξσSI) towards lower SI

cross sections (ξσSI < 10-6 pb)

Similar effect for whatever considered model framework

Supersymmetric expectations in MSSM

•Assuming for the neutralino a dominant purely SI coupling

•when releasing the gaugino mass unification at GUT scale:

M1/M2≠0.5 (<); (where M1 and M2 U(1) and SU(2) gaugino masses)

low mass configurations are obtained

figure taken from PRD69(2004)037302

scatter plot of theoretical configurations vs DAMA/NaI allowed region in the given model frameworks for the total DAMA/NaI exposure (area inside the green line);

(for previous DAMA/NaI partial exposure see PRD68(2003)043506)

Some open scenarios on astrophysical Some open scenarios on astrophysical aspectsaspects

In the galactic halo, fluxes of Dark Matter particles with dispersion velocity relatively low are expected:

some relics of the hierarchical assembly of the Milky Way are already observed in the visible: Sagittarius dwarf galaxy since 1994, Canis Major galaxy early discovered…

This scenario foreseen streams of Dark Matter particles with lowvelocity dispersion, very interesting for direct detection: Sm/S0enhanced in A.M., new signature for streams

La galassia La galassia ““nananana”” Sagittario (Sgr) e lSagittario (Sgr) e l’’alone di materia oscuraalone di materia oscura……Nel 1994 –1995 e’ stato osservato un nuovo oggetto “Sagittarius Dwarf Elliptical Galaxy” nelle vicinanze dellaVia Lattea, nella direzione del centrogalattico, ed in posizione opposta ad essorispetto al Sistema Solare

La direzione di moto della Sgr era molto diversa da quella degli altri oggetti luminosinella Via Lattea, così si è scoperto che le stelle osservate appartenevano ad una galassianana satellite della Via Lattea, che sta per essere catturata. La galassia nana ha assuntouna forma molto allungata a causa delle forze di marea subite durante le circa 10 rivoluzioni effettuate attorno alla Via Lattea.

La galassia sferoidale La galassia sferoidale ““nananana”” Sagittario, satellite della Via LatteaSagittario, satellite della Via Lattea

(Ibata et al. 1994)(Ibata et al. 1994)

il Sole disterebbepochi kpc dalcentro della coda trainante...:

E’ atteso un flusso di particelle costituenti la materia oscuradell’alone galattico di Sgr, convelocità ortogonale al nostropiano galattico di circa 300 km/s.

da astro-ph/0309279:

sun

sgr

stream

Densità dello stream attesa:[1 -- 80] 10-3 GeV/cm3 (0.3-25)% di ρhalo

Velocità locale media dello stream ricavata dalle misure su 8 stelle locali attribuite alla coda trainante di Sgr:

(290±26) km/s nella direzione (l,b)=(116,-59): (Vx,Vy,Vz)=(-65±22, 135±12,-249±6)km/s

Dispersione delle velocità:(σvx,σvy,σvz)=(63,33,17)km/s

Altri stream di materia oscura da Altri stream di materia oscura da galassie satelliti della Via Lattea galassie satelliti della Via Lattea

vicini al Sole?vicini al Sole?

Canis Major simulation:

Astro-ph/0311010 Ibata et al.

Posizione del Sole: (-8,0,0)kpc

.....molto probabile....

E’ ipotizzato che le galassie a spirale come la Via Lattea siformano per cattura delle vicinegalassie satelliti come la Sgr, Canis Major ecc…

... investigating halo substructures by underground exptthrough annual modulation

Possible contributions due to the tidal stream of Sagittarius Dwarf satellite (SagDEG) galaxy of Milky Way

EPJC47(2006)263

sunstream

spherical oblate

V8*

Vsph Vobl

V8* from 8 local stars: PRD71(2005)043516

simulations from Ap.J.619(2005)807

Examples of the effect of SagDEG tail on the phase of the signal annual modulation

5 10E (keVee)

180

160

140

120t 0

(day

)

mW=70 GeV

DAMA/NaI results:(2-6) keV t0 = (140±22) d

Ex. NaI:3 105 kg d

NFW spherical isotropic non-rotating, v0 = 220km/s, ρ0min+ 4% SagDEG

NFW spherical isotropic non-rotating, v0 = 220km/s, ρ0max + 4% SagDEG

Expected phase in the absence of streams t0 = 152.5 d (June 2nd)

Investigating the effect of Sagittarius Dwarf satellite galaxy(SagDEG) for WIMPs EPJC47 (2006) 263

sunstreamDAMA/NaI: seven annual cycles 107731 kg d for some SagDEG modelling

pure SI case

pure SD case:examples of slices of the 3-dim allowed volumeFew examples

green areas: no SagDEG

The higher sensitivity of DAMA/LIBRA will allow to more effectively investigate the presence and the contributions of streams in the galactic halo

Possible contributions due to the tidal stream of Sagittarius Dwarf satellite (SagDEG) galaxy of Milky Way

Constraining the SagDEG stream by DAMA/NaI - 2EPJC47(2006)263for different SagDEG velocity dispersions (20-40-60 km/s)

pure SI case

pure SD case

This analysis shows the possibility to investigate local halo features by annual modulation signature already at the level of sensitivity provided by DAMA/NaI, allowing to reach sensitivity to SagDEG density comparable with M/L evaluations.

The higher sensitivity of DAMA/LIBRA will allow to more effectively investigate the presence and the contributions of streams in the galactic halo

What about the indirect searches of DM particles in the space?

astro-ph/0211286

The EGRET Excess of Diffuse Galactic Gamma RaysIt was already noticed in 1997 that the EGRET data showed an excess of gamma ray fluxes for energies above 1 GeV in the galactic disk and for all sky directions.

EGRET data, W.de Boer, hep-ph/0508108

interpretation, evidence itself, derived mW and cross sections depend e.g. on bckg modeling, on DM spatial velocity distribution in the galactic halo, etc.

In next years new data from DAMA/LIBRA (direct detection) and from Agile, Glast, Ams2, Pamela, ... (indirect detections)

PLB536(2002)263

Hints from indirect searches are not in conflict with DAMA/NaI for the WIMP class candidate

... not only neutralino, but also e.g. ...

PLB536(2002)263... sneutrino, ...

... or neutrino of 4th familyhep-ph/0411093

Example of joint analysis of DAMA/NaI and positron/gamma’s excess in the space in the light of two DM particle components in the halo

in the given frameworks in the given frameworks

... or Kaluza-Klein DMPRD70(2004)115004

IJMPA21 (2006) 1445Another class of DM candidates:

light bosonic particles

The detection is based on the total conversion of the absorbed bosonic mass into electromagnetic radiation.

In these processes the target nuclear recoil is negligible and not involved in the detection process (i.e. signals from these candidates are lost in experiments

applying rejection procedures of the electromagnetic contribution)

Axion-like particles: similar phenomenology with ordinary matter as the axion, but significantly different values for mass and coupling constants allowed.

A wide literature is available and various candidate particles have been and can be considered.

A complete data analysis of the total 107731 kgxday exposure from DAMA/NaI has been performed for pseudoscalar (a) and scalar (h) candidates in some of the possible scenarios.

,h ,h h

a S0 S0,Sm S0,Sm

h S0,Sm S0 S0,Sm

Main processes involved in the detection:

They can account for the DAMA/NaI observed effect as well as candidates belonging to the WIMPs class

They can account for the DAMA/NaI observed effect as well as candidates belonging to the WIMPs class

Axioelectric contribution dominant in all “natural”cases → allowed region almost independent on the other fermion coupling values

Also this can account for the DAMA/NaI observed effect

Allowed multiAllowed multi--dimensional volume in the space defined by mdimensional volume in the space defined by maa and all coupling and all coupling constants to charged fermions (3constants to charged fermions (3σσ C.L.) in the given frameworksC.L.) in the given frameworks

only electron coupling

cosmological interest:at least below

Analysis of 107731 kg day exposure from DAMA/NaI.

Maximum allowed photon coupling

UHECR - PRD64(2001)096005

033 949

1≈⎥

⎤⎢⎣

⎡++≈

u

uua

d

dda

e

eeaa m

gmg

mgg

πα

γγ

Majoron as in PLB99(1981)411; coupling to photons vanish at first order:

⎟⎟⎠

⎞⎜⎜⎝

⎛−==

u

uua

d

dda

e

eea

mg

mg

mg

coupling model

The The pseudoscalarpseudoscalar casecase

Di Lella, ZioutasAP19(2003)145

IJMPA21 (2006) 1445

1) electron coupling does not provide modulation2) from measured rate: ghee < 3 10-16 to 10-14 for mh ≈ 0.5 to 10 keV3) coupling only to hadronic matter: allowed region in vs. mh

(3σ C.L.)NNh

g

Allowed multiAllowed multi--dimensional volume in the space defined by mdimensional volume in the space defined by mhh and all the coupling and all the coupling constants to charged fermions (3constants to charged fermions (3σσ C.L.) in the given frameworksC.L.) in the given frameworks

Also this can account for the DAMA/NaI observed effect

h configurations of cosmological interest in plane

DAMA/NaI allowed region in the considered framework.

• Allowed by DAMA/NaI (for mh > 0.3 keV )• τh > 15 Gy (lifetime of cosmological interest)• mu = 3.0 ± 1.5 MeV md = 6.0 ± 2.0 MeV

Many other configurations of cosmological interest Many other configurations of cosmological interest are possible depending on the values of the are possible depending on the values of the couplings to other quarks and to gluonscouplings to other quarks and to gluons……..

•• Annual modulation signature present for a scalar Annual modulation signature present for a scalar particle with pure coupling to hadronic matter particle with pure coupling to hadronic matter (possible gluon coupling at tree level?).(possible gluon coupling at tree level?).

•• ComptonCompton--like to nucleus conversion is the dominant like to nucleus conversion is the dominant process for particle with cosmological lifetime. process for particle with cosmological lifetime.

ghuu vs ghdd

( ) ( )ddhuuhddhuuhNNh ggAZggg −++= 2

If all the couplings to quarks of the same order: lifetime dominated by uand d loops:

⎥⎦

⎤⎢⎣

⎡+−≈−≈ ∑

d

ddh

u

uuh

q q

qqhqh m

gmg

mgQ

g 91

942

232

πα

πα

γγ

The scalar caseThe scalar caseIJMPA21(2006)1445

FAQ:FAQ:... DAMA/NaI ... DAMA/NaI ““excludedexcluded”” by CDMSby CDMS--II (and others)?II (and others)?

OBVIOUSLY NOThey give a single model dependent result using natGe targetDAMA/NaI gives a model independent result using 23Na and 127I targets

Even assuming their expt. results as they give them …

No direct model

independent

comparison possible

•In general? OBVIOUSLY NOThe results are fully “decoupled” either because of the different sensitivities to the various kinds of candidates, interactions and particle mass, or simply taking into account the large uncertainties in the astrophysical (realistic and consistent halo models, presence of non-thermalized components, particle velocity distribution, particle density in the halo, ...), nuclear (scaling laws, FFs, SF) and particle physics assumptions and in all the instrumental quantities (quenching factors, energy resolution, efficiency, ...) and theor. parameters.

•At least in the purely SI coupling they only consider? OBVIOUSLY NO

still room for compatibility either at low DM particle mass or simply accounting for the large uncertainties in the astrophysical, nuclear and particle physics assumptions and in all the expt. and theor. parameters.

Case of DM particle scatterings on target-nuclei

Case of bosonic candidate (full conversion into electromagnetic radiation)•These candidates are lost by these expts. OBVIOUSLY NO

(see also in Riv. N. Cim. 26 n. 1(2003)1-73 and IJMPD13(2004)2127, several papers in literature, astro-ph/0511262)

As a result of a second generation R&D for more radiopure NaI(Tl) by exploiting new chemical/physical radiopurification techniques

(all operations involving crystals and PMTs - including photos - in HP Nitrogen atmosphere)

The new DAMA/LIBRA set-up ~250 kg NaI(Tl)(Large sodium Iodide Bulk for RAre processes)

The new DAMA/LIBRALIBRA set-up ~250 kg ~250 kg NaI(TlNaI(Tl))(Large sodium Iodide Bulk for RAre processes)

etching staff at workin clean room

PMT+HV divider

Cu etching with super- and ultra-

pure HCl solutions, dried and sealed in

HP N2

improving installationand environment

storing new crystals

detectors during installation; in the central and right up

detectors the new shaped Cu shield surrounding light guides (acting also as optical windows)

and PMTs was not yet applied

view at end of detectors’installation in the Cu box

closing the Cu boxhousing the detectors

(all operations involving crystals and PMTs -including photos- in HP N2 atmosphere)

installing DAMA/LIBRA detectors

filling the inner Cu box with further shield

assembling a DAMA/ LIBRA detectorDAMA/LIBRA in data taking since March 2003,waiting for a larger exposure than DAMA/NaI

Some infos about DAMA/LIBRA data acquisition

DAMA/LIBRA in operation since March 2003

e.g. up to March 2006: exposure: of order of 105 kg x doverall sources’ data: of order of 4 x 107 events

Few examples of operational features (here from March 2003 to August 2005):

%4.7)60( =keVEσ

241241Am routine Am routine calibrationscalibrations((allall the the detectorsdetectors togethertogether))

E (keV)

tdcaltdcaltdcal −

freq

uenc

y

σ=0.4%

StabilityStability of the of the lowlow energyenergycalibrationcalibration factorsfactors

ratio of the peaks’ positions

2≈α

σ=0.9%

HE

HEHE

fff −

freq

uenc

y

StabilityStability of the high of the high energyenergy calibrationcalibration

factorsfactors

Perspectives of DAMA/LIBRAPerspectives of DAMA/LIBRAModel independent approach: Model independent approach: reachable C.L. as function of running time and of the low energy bckg rate. The shaded regions account for several model frameworks.

e.g., role of the increase of statistics and of the improvement in the bckg rate to identify a SI/SD coupled WIMP candidate in a particular given model framework of the many possible

• Allowed regions evaluated by simulating the response of the ~250 kg NaI(Tl) set-up to a WIMP having mW=60GeV, σSI=10-6 pb, σSD=0.8 pb and θ=2.435rad.

• Various exposure times are considered (from 1 to 5y).• In each panel different bckg rate.

More complete scenarios would be investigated and several uncertainties accounted for (see e.g. Riv.N.Cim.26n.1(2003)1-73)

Assumptions:

• 1σ C.L.• v0=220km/s,

fixed params• isothermal

spherical halo• etc.

Example of corollary model dependent quests for the candidate particle in a single simplified model/analysis framework:

…… other astrophysical scenarios?other astrophysical scenarios?Possible non-thermalized multicomponent galactic halo? In the galactic halo, fluxes of Dark Matter particles with dispersion velocity relatively low are expected :

sunstream

OtherOther darkdark matter stream frommatter stream from satellitesatellite galaxygalaxyofof MilkyMilky WayWay close toclose to thethe SunSun??

.....very likely....Can be guess that spiral galaxy like Milky Way have been formed capturing close satellite galaxy as Sgr, Canis Major, ecc…

Canis Major simulation: astro-ph/0311010

Position of the Sun: (-8,0,0) kpc

Effect on the phase ofannual modulation

signature?

Effect on |Sm/So| respect to “usually”

adopted halo models?

Interesting scenarios for DAMA

Possible contribution due to the tidal stream of Sagittarius Dwarf satellite galaxy of Milky Way

K.Freese et al. astro-ph/0309279

Possible presence of caustic rings

⇒ streams of Dark Matter particles

Fu-Sin Ling et al. astro-ph/0405231

An example of possible signature for the An example of possible signature for the presence of streams in the Galactic halopresence of streams in the Galactic halo

The effect of the streams on the phase depends on the galactic halo model

Phas

e(d

ay o

f max

imum

)

E (keVee)

Expected phase in the absence of streams t0 = 152.5 d (2nd June)

NFW spherical isotropic non-rotating, v0=220km/s, ρ0 max + 4% Sgr

Evans’log axisymmetric non-rotating,v0=220km/s, Rc= 5kpc, ρ0 max + 4% Sgr

The higher The higher sensitivity sensitivity ofof DAMA/LIBRADAMA/LIBRAwill allow to more effectively investigate will allow to more effectively investigate the presence or contributions of the presence or contributions of streamsstreams

in the in the galactic halogalactic haloDAMA/NaI results:(2-6) keV t0 = (140 ± 22) d

Example, NaI: 3 105 kg d

ConclusionsConclusionsDark Matter investigation is a crucial challenge in the incomingDark Matter investigation is a crucial challenge in the incoming years for years for cosmology and for physics beyond the standard modelcosmology and for physics beyond the standard model

DAMA/NaI data show aDAMA/NaI data show a 6.36.3σσ C.L. model independent evidenceC.L. model independent evidence for the for the presence of a Dark Matter particle component in the galactic halpresence of a Dark Matter particle component in the galactic haloo

Corollary model dependent quest for the candidate particle:• WIMP particles with mw~ (few GeV to TeV) with coupling pure SI or pure SD or

mixed SI/SD as well as particles with preferred inelastic scattering (Riv.N.Cim. 26 n.1. (2003) 1-73, IJMPD 13 (2004) 2127)

• several other particles suggested in literature by various authors(see literature)

• bosonic particles with ma~ keV having pseudoscalar, scalar coupling(IJMPA21(2006)1445)

• halo substructures (SagDEG) effects (EPJC 47 (2006) 263)• and more in progress...

The presently runningThe presently running DAMA/LIBRADAMA/LIBRA will allow to further increase the C.L. will allow to further increase the C.L. of the model independent result, to restrict the nature of the cof the model independent result, to restrict the nature of the candidate andidate and to investigate the phase space structure of the dark haloand to investigate the phase space structure of the dark halo

+ a new R&D towards a possible ton set-up we proposed in 1996 in progress... wait for more in the near future


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