P. Belli

INFN-Roma2

The Progress of the The Progress of the DAMA experimentDAMA experiment

IHEP - Beijing Dec. 2005

The The Dark SideDark Side of the Universe: of the Universe: experimental evidences ...experimental evidences ...

First evidence and confirmations:

1933 F. Zwicky: studying dispersion velocity of Coma galaxies

1936 S. Smith: studying the Virgo cluster1974 two groups: systematical analysis of mass

density vs distance from center in many galaxies COMA Cluster

Other experimental evidencesfrom LMC motion around Galaxy

from X-ray emitting gases surrounding elliptical galaxies

from hot intergalactic plasma velocity distribution in clusters

Milky WayRotational curve of a spiral galaxy

Mvisible Universe

Primordial Nucleosynthesis

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

;73.0≈ΩΛ

““Concordance modelConcordance model””

WMAP

Supernovae IA

;27.0

Ω = ΩM + ΩΛ=1.02±0.02

≈ΩM

The 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 formation in the Universe

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 candidate)

Heavy candidates:• In thermal equilibrium in the early stage of Universe• Non relativistic at decoupling time ~ 10-26/ΩWIMPh2 cm3s-1 → σordinary matter ~ σweak• Expected flux: Φ ~ 107 . (GeV/mW) cm-2 s-1 (0.2

Direct detection: Various approaches and techniques (many still at R&D stage) Various different target nucleiVarious different experimental site depths

Ionization:Ge, Si

Scintillation:NaI(Tl), LXe,CaF2(Eu),...Bolometer:TeO2, Ge, ...

W

W’

N

Recently, another possibility has been considered: the direct ionization/excitation in the detector by axion-like particles

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

December30 km/s

~ 232 km/s60°

June

30 km/s

DrukierDrukier,,FreeseFreese,,SpergelSpergel PRD86PRD86FreeseFreese et al. PRD88et 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)]

Sk[η(t)] =dRdER

dER ≅ S0,k +∆Ek∫ Sm ,k cos[ω (t − t0 )]

Investigating the presence of a Dark Matter particles component Investigating the presence of a Dark Matter particles component in the in the galactic halo by the model independent annual modulation signatugalactic halo by the model independent annual modulation signaturere

1) Modulated rate according cosine2) In a definite low energy range3) With a proper period (1 year)4) With proper phase (about 2 June)5) For single hit events in a multi-

detector set-up6) With modulation amplitude in the

region of maximal sensitivity must be

Competitiveness of NaI(Tl) setCompetitiveness of NaI(Tl) set--upup• High duty cycle • Well known technology • Large mass possible• “Ecological clean” set-up; no safety problems• Cheaper than every other considered technique• Small underground space needed• High radiopurity by selections, chem./phys. purifications, protocols reachable• Well controlled operational condition feasible• Routine calibrations feasible down to keV range in the same conditions as the production runs• Neither re-purification procedures nor cooling down/warming up (reproducibility, stability, ...) • Absence of microphonic noise + effective noise rejection at threshold (τ of NaI(Tl) pulses hundreds

ns, while τ of noise pulses tens ns)• High light response (5.5 -7.5 ph.e./keV)• Sensitive to SI, SD, SI&SD couplings and to other existing scenarios, on the contrary of many other

proposed target-nuclei• Sensitive to both high (by Iodine target) and low mass (by Na target) candidates• Effective investigation of the annual modulation signature feasible in all the needed aspects• PSD feasible at reasonable level• etc.

A low background NaI(Tl) also allows the study of several other rare processes such as: possible processes violating the Pauli exclusion principle, CNC processes in 23Na and 127I, electron stability, nucleon and di-nucleon decay into invisible channels, neutral SIMP and nuclearites search, solar axion search, ...

High benefits/cost

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 136Xe• 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

Xenon01

PLB527(2002)182

PLB546(2002)23

INFN/EXP-08/03+Proc.

INFN/EXP-08/03+NPA-II

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

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, astro-ph/0511262 (IJMPA in press)

• 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

• 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

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

•• data taking of each annual cycledata taking of each annual cycle starts from autumn/winter (when cosw(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 Main procedures of the DAMA data of the DAMA data taking for taking for thethe DMp annual modulation signatureDMp annual modulation 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 bySupronyl (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

Time (day)

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) ) cpdcpd/kg/keV /kg/keV tt00 = (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--44Solid 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) ) cpdcpd/kg/keV/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”

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

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.

(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 possible systematicssystematics or side reactionsor side reactions

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

RADON Sealed Cu box in HP Nitrogen atmosphere,etc

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

Sm(thermal n) < 10-5 cpd/kg/keV (< 0.05% Smobserved)

In all the cases of neutron captures (24Na, 128I, ...) a possible thermal n modulation induces a variation

in all the energy spectrumAlready excluded also by R90 analysis

HYPOTHESIS: assuming very cautiously Φn=10-6 n cm-2 s-1 and a 10% thermal neutron modulation:

Can a possible thermal neutron modulation Can a possible thermal neutron modulation account for the observed effect?account for the observed effect?

•• Experimental limit on the neutrons flux Experimental limit on the neutrons flux ““survivingsurviving”” the neutron shield in the neutron shield in the DAMA/NaI setthe DAMA/NaI set--up:up:

less sensitive approach: studying some neutron activation channels (N.Cim.A112(1999)545):

Φn < 5.9 10-6 n cm-2 s-1more sensitive approach: studying triple coincidences able to give

evidence for the possible presence of 24Na from neutron activation (derivable from EPJA24(2005)51):

Φn < 4.0 10-7 n cm-2 s-1

Capture rate = Φn σn NT = 0.17 capture/d/kg • Φn/(10-6 n cm-2 s-1)For ex., neutron capture in 23Na: 23Na(n,γ)24Na; 23Na(n,γ)24mNa

Evaluation of the expected effect:

24mNa (T1/2=20ms)σn = 0.43 barnσn = 0.10 barn

NONO

E (MeV)

MC simulation of the process

1.4·10-3 cpd/kg/keV7·10-5 cpd/kg/keV

When Φn = 10-6 n cm-2 s-1:

••Thermal neutrons flux measured at LNGS :Thermal neutrons flux measured at LNGS :Φn = 1.08 10-6 n cm-2 s-1 (N.Cim.A101(1989)959)

(cautiously adopted here and in all the DAMA calculations)

Can a possible fast neutron modulation Can a possible fast neutron modulation account for the observed effect? NOaccount for the observed effect?

By MC: differential counting rateabove 2 keV ≈ 10-3 cpd/kg/keV

In the estimate of the possible effect of the neutron background cautiously not included the 1m concrete moderator, which almost completely surrounds (mostly outside the barrack) the passive shield

Measured fast neutron flux @ LNGS:Φn = 0.9 10-7 n cm-2 s-1 (Astropart.Phys.4 (1995),23)

HYPOTHESIS: Assuming - very cautiously - a 10% neutron modulation: Sm

(fast n) < 10-4 cpd/kg/keV (< 0.5% Smobserved)

Moreover, a possible fast n modulation would induce:a variation in all the energy spectrum (steady environmental fast neutrons always accompained by thermalized component)

already excluded also by R90a modulation amplitude for multiple-hit events different from zero

already excluded by the multiple-hit events (see also elsewhere)

Thus, a possible 5% neutron modulation (ICARUS TM03-01) cannot quantitatively contribute to the DAMA/NaI observed signal, even if the neutron flux would be assumed 100 times larger than measured by various authors over more than 15 years @ LNGS

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 account for the observed effect

To investigate the nature and coupling with ordinary matter of the possible DM candidate, an 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

Corollary quest for a candidate

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

self-interacting dark matter

Kaluza-Klein particles

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 candidate)

astrophysical models: ρDM, velocitydistribution and its parameters

nuclear Physics modelsexperimental parameters

THUSuncertainties on models

and comparisons

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

+ different scenarios

+

DM particleDM particle--nucleus elastic scatteringnucleus elastic scattering

dσdER

(v,ER) =dσdER

⎛

⎝ ⎜ ⎞

⎠ ⎟

SI

+ dσdER

⎛

⎝ ⎜ ⎞

⎠ ⎟

SD

=

2GF2mN

πv2Zgp + (A− Z)gn[ ]2 FSI2 (ER) + 8 J +1J ap Sp + an Sn[ ]

2FSD

2 (ER )⎧ ⎨ ⎩

⎫ ⎬ ⎭

SI+SD differential cross sections:gp,n(a p,n) effective DM particle-nucleon couplings

nucleon spin in the nucleus

F2(ER) nuclear form factors

mWp reduced DM particle-nucleon massGeneralized SI/SD DM particle-nucleon cross sections:

σSI =4π

GF2mWp

2 g2 σSD =32π

34

GF2 mWp

2 a 2 g = gp + gn2

• 1 −gp − gngp + gn

1−2ZA

⎛ ⎝

⎞ ⎠

⎡

⎣ ⎢ ⎤

⎦ ⎥

a = ap2 + an

2 tgθ =anap

where:g: independent on the used target nucleus since Z/A nearly

constant for the nuclei typically used

Differential energy distribution:dRdER

= NTρWmW

dσdERvmin(ER )

vmax

∫ (v, ER )vf(v)dv = NTρWmN

2mWmWp2 ⋅ Σ(ER ) ⋅ I(ER)

I(ER) =f (v)vv min (ER )

vmax

∫ dv vmin =mN ER2mWN

2

(ER ) = A2σ SIFSI

2 (ER) +43

J +1J

σSD Sp cosθ + Sn sinθ[ ]2 FSD2 (ER )⎧ ⎨ ⎩ ⎫ ⎬ ⎭

NT: number of target nuclei

f(v): DM particle velocity distribution in the Earth frame (it depends on ve)

ve=vsun+vorbcosωt

vmax: maximal DM particle velocity in the Earth frame

minimal velocity providing ER recoil energy

Σ

The inelastic DM The inelastic DM –– nucleus interaction: W + N nucleus interaction: W + N →→ WW** + N+ N

Differential energy distribution for SI interaction:

• 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 mNbecomes increasingly severe for low mN Ex. mW =100 GeV

mN µ70 41

130 57

12

µv2 ≥ δ ⇔ v ≥ vthr =2δµ

[ ] 22

2222

22

* 1)()( vvqFgZAZgmG

dd thr

SInpWNF −⋅−+=

Ω πσ

Nucleus recoil energy:

2

cos12

12*

2

2

2

2

22 θ⋅−−−⋅= v

vv

v

mvmE

thrthr

N

WNR

Differential energy distribution:

∫=max

min

)(),(v

vR

RW

WT

R

dvvvfEvdEd

mN

dEdR σρ

⎟⎟⎠

⎞⎜⎜⎝

⎛+⋅=

RN

WN

WN

RNR Em

mm

EmEv δ12

)( 2min

gp,n effective DM particle-nucleon couplingsdΩ* differential solid angle in the DM-nucleon c.m. frameq2 = squared threee-momentum transfer

[ ] )()(2 2222

RSInpNF

R

EFgZAZgvmG

dEd

−+=π

σ

Sm/S0 enhanced with respect to the elastic scattering case

Spin Independent

2( ) /5nqre−2 2

1 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 =anap

(0≤θ

Astrop. Phys.3(1995)361

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

assumed 1 (see also NIMA507(2003)643)

• 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 vis

1010 10610100 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

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

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 (

DAMA/NaI CDMS-II Edelweiss-I ZeplinZeplin--II CresstCresst--IIII

• Signature annual modulation none none none none• Targets 23Na, 127I natGe natGe natXe CaWO4• Technique widely known poorly experienced poorly experienced liq/gas optical interface poorly experienced

(known just by Edelweiss) (known just by CDMS) (light collected from top) (known just by themselves)

• Target mass ≈ 100 kg 0.75 kg 0.32 kg ≈ 3 kg ≈ 0.6 kg• Used exposure ~(1.1 × 105) kg × day 19.4 kg × day 30.5 kg × day 280 kg × day 20.5 kg x day

(RivNCim 26 n1(2003)1-73) (astro-ph/0405033) (NDM03) (Moriond03) (astro-ph/0408006)• Expt. depth 1400 m 780 m 1700 m 1100 m 1400 m• Neutron shield ~1m of concrete + 10/40 cm 50 cm polyethylene 30 cm paraffin --- none

polyethylene/paraffin +1.5 mm Cd

• Energy threshold 2 keVee 10 keVee 20 keVee 2 keVee (but: σ/E=100% 12 keVee(5.5 – 7.5 p.e./keV) and 1 p.e./keVee!!!; IDM02)

(2.5 p.e./keVee; Moriond03)• Quenching factor measured assumed 1 assumed 1 (see also measured assumed 1

NIMA507(2003)643)

• Measured evt rate ~1 cpd/kg/keV ??(claimed γ>than CDMS-I ~ 104 events total ~100 cpd/kg/keV (IDM02) (??) 6 cpd/kg/keVin low energy range where ~60 cpd/kg/keV, above 35 keVee

105 events)• Claimed evts after 0 o 1 2 (claimed taken ~20-50 cpd/kg/keV after 16rejection procedures in a noisy period!) filtering (?) and ?? after PSD

(Moriond03, IDM02) • Evts satisfying modulation amplitudethe signature integrated over the given insensitive insensitive insensitive insensitivein DAMA/NaI exposure some 103 evts

• Expected number from few down to zero from few down to zero depends on the model from few down to zeroof evts from depending on the model depending on the model framework, also zero depending on the model DAMA/NaI effect frameworks framework framework

(and on quenching factor) (and on quenching factor) (and on quenching factor)

DAMA/DAMA/NaINaI vs some vs some othersothers

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 …

•In general? OBVIOUSLY NOThe different sensitivities to the various kinds of candidates, interactions and particle mass, the accounting for realistic and consistent halo models and accounting for existing parameters uncertainties, FFs and/or SF and existing uncertainties on related parameters, different scaling laws than assumed (possible even for the neutralino candidate), their proper accounting for experimental parameters and related uncertainties, the many possible scenarios, etc. fully “decouple” the results.

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

they give a single result fixing all the astrophysical, nuclear and particle physics assumptions and all the expt. and theor. parameters values ….; moreover, they usually quote in an uncorrect, partial and unupdated way the implications of the DAMA/NaI model independent result…; see above, etc.

No direct model

independent

comparison possible

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

HEAT data as analysedin PRD65(2002)057701

ν’s of 4th family hep-ph/0411093

Example of joint analysis of DAMA/NaI and

positron/gamma’s excess in the space

in the given frameworks in the given frameworks

Some measurements performed by indirect search experiments have pointed out the presence of antiparticles and photons which could be ascribed to some classes of Cold Dark Matter particles annihilating in the halo

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

astro-ph/0211286

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

In next years new data from DAMA/LIBRA and for indirect searches from Agile, Glast, Ams2, Pamela, ...

,h ,h h

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

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

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)

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.

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 a S0 S0,Sm S0,Sm

h S0,Sm S0 S0,Sm

Main processes involved in the detection:

Another class of DM candidates: light bosonic particle

Another class of DM candidates: light bosonic particle

astro-ph/0511262 (IJMPA, in press)

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 pseudoscalar caseThe pseudoscalar caseastro-ph/0511262 (IJMPA, in press)

Di Lella, ZioutasAP19(2003)145

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 dimensional volume in the space defined by mmhh and all the and all the coupling constants to charged fermions (3coupling constants 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 particle with pure coupling to hadronichadronic matter 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 case astro-ph/0511262 (IJMPA, in press)

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

in the DAMA experiment

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

in the DAMA experiment

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

DAMA/LIBRA performance: DAMA/LIBRA performance: energyenergy scale andscale and calibrationscalibrations

tdcaltdcaltdcal −

freq

uenc

y

%4.7)60( =keVEσ

σ=0.9%

March 2003 – April 2005

HE

HEHE

fff −

freq

uenc

y

Period:March 2003 –August 2005

241Am routine calibrations(all the detectors together)

Stability of the high energy calibration factors (ADCs)

E (keV)

σ=0.4%

Stability of the low energy calibration factors (TDs)ratio of the peaks’ positions

2≈α

ExampleExample of theof the stabilitystability of the highof the high energyenergy rate, rate, RR9090, (, (aboveabove 90 keV) 90 keV)

σ=1.2%

•• RR9090 percentage variations with percentage variations with respect to their mean values for respect to their mean values for single crystalsingle crystal

DAMA/LIBRA

(from March 2003 – August 2004)

…… 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

DAMA/LIBRADAMA/LIBRA perspectivesperspectivesDAMA/LIBRA DAMA/LIBRA (~250kg NaI(Tl)), running since March 2003, (~250kg NaI(Tl)), running since March 2003, can allow to: can allow to:

• achieve higher C.L. for the annual modulation effect (model independent result)• investigate many topics on the corollary model dependent quests for the

candidate particle (continuing and improving past and present efforts on the data of the previous DAMA/NaI experiment):

+ on different astrophysical scenarios + on different dark matter particles distributions + on different scaling laws+ on different possible CDM candidates+ on different couplings ...and more

• competitive limits on many rare processes can also be obtained…wait for an exposure larger than DAMA/NaI

...and beyond?...and beyond?• R&D-III approved and funded by INFN towards a possible multi-purpose

NaI(Tl) ton set-up we propsed in 96 » work in progress

• new ideas to fully exploit Cold Dark Matter particle signal peculiarities and halo features under study

SummarySummaryDAMA/NaI data show a 6.3σ C.L. model independent evidence for the

presence of a Dark Matter particle component in the galactic halo

This evidence allows to investigate new physicsbeyond the Standard Model:

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

(astro-ph/0511262, IJMPA, in press)

DAMA/LIBRA will allow to further restrict the nature of the candidate and to investigate the

phase space structure of the dark halo

Final model independent result by DAMA/NaICorollary quest for a candidateQuenching factorAnother class of DM candidates: light bosonic particle