Upgrading DAMALIBRA R Cerulli INFNLNGS Congresso Nazionale SIF

Upgrading DAMA/LIBRA R. Cerulli INFN-LNGS Congresso Nazionale SIF Bologna, 20 -24 Settembre 2010

DAMA/LXe DAMA/R&D low bckg DAMA/Ge for sampling meas. DAMA/Na. I DAMA/LIBRA http: //people. roma 2. infn. it/dama

Some direct detection processes: • Scatterings on nuclei • Inelastic Dark Matter: W + N W* + N detection of nuclear recoil energy W has Two mass states + , - with d mass splitting Kinematical constraint for the inelastic scattering of - on a nucleus • Excitation of bound electrons in scatterings on nuclei detection of recoil nuclei + e. m. radiation • Conversion of particle into e. m. radiation detection of , X-rays, a X-ray e- • Interaction only on atomic electrons detection of e. m. radiation DMp g e- • Interaction of light DMp (LDM) on e- or nucleus with production of a lighter particle detection of electron/nucleus recoil energy e. g. signals from these candidates are completely lost in experiments based on “rejection procedures” of the e. m. component of their rate e. . . even WIMPs e. g. sterile … also other ideas … • … and more

The annual modulation: a model independent signature for the investigation of Dark Matter particles component in the galactic halo With the present technology, the annual modulation is the main model independent signature for the DM signal. Although the modulation effect is expected to be relatively small a suitable large-mass, low-radioactive set-up with an efficient control of the running conditions would point out its presence. Drukier, Freese, Spergel PRD 86 Freese et al. PRD 88 Requirements of the annual modulation 30 km December /s 1) Modulated rate according cosine 2) In a definite low energy range 3) With a proper period (1 year) ~ June 30 23 2 k m /s 60° km /s • vsun ~ 232 km/s (Sun velocity in the halo) • vorb = 30 km/s (Earth velocity around the Sun) • = p/3, w = 2 p/T , T = 1 year • t 0 = 2 nd June (when v is maximum) v (t) = vsun + vorb cos[w(t-t 0)] Expected rate in given energy bin changes because the annual motion of the Earth around the Sun moving in the Galaxy 4) With proper phase (about 2 June) 5) Just for single hit events in a multi-detector set-up 6) With modulation amplitude in the region of maximal sensitivity must be <7% for usually adopted halo distributions, but it can be larger in case of some possible scenarios To mimic this signature, spurious effects and side reactions must not only - obviously - be able to account for the whole observed modulation amplitude, but also to satisfy contemporaneously all the requirements The DM annual modulation signature has a different origin and, thus, different peculiarities (e. g. the phase) with respect to those effects connected with the seasons instead

DAMA/Na. I: 100 kg Na. I(Tl) Performances: N. Cim. A 112(1999)545 -575, EPJC 18(2000)283, Riv. N. Cim. 26 n. 1(2003)1 -73, IJMPD 13(2004)2127 Results on rare processes: • 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 PLB 408(1997)439 PRC 60(1999)065501 PLB 460(1999)235 PLB 515(2001)6 EPJdirect C 14(2002)1 EPJA 23(2005)7 EPJA 24(2005)51 Results on DM particles: • • PSD Investigation on diurnal effect Exotic Dark Matter search Annual Modulation Signature PLB 389(1996)757 N. Cim. A 112(1999)1541 data taking completed on July 2002, last data release 2003. Still producing results PRL 83(1999)4918 PLB 424(1998)195, PLB 450(1999)448, PRD 61(1999)023512, PLB 480(2000)23, EPJC 18(2000)283, PLB 509(2001)197, EPJC 23(2002)61, PRD 66(2002)043503, Riv. N. Cim. 26 n. 1 (2003)1, IJMPD 13(2004)2127, IJMPA 21(2006)1445, EPJC 47(2006)263, IJMPA 22(2007)3155, EPJC 53(2008)205, PRD 77(2008)023506, MPLA 23(2008)2125. model independent evidence of a particle DM component in the galactic halo at 6. 3σ C. L. total exposure (7 annual cycles) 0. 29 ton x yr

The new DAMA/LIBRA set-up ~250 kg Na. I(Tl) (Large sodium Iodide Bulk for RAre processes) As a result of a second generation R&D for more radiopure Na. I(Tl) by exploiting new chemical/physical radiopurification techniques (all operations involving crystals and PMTs - including photos - in HP Nitrogen atmosphere) 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 installing DAMA/LIBRA detectors assembling a DAMA/ LIBRA detector filling the inner Cu box with further shield • Radiopurity, performances, procedures, etc. : NIMA 592(2008)297 • Results on DM particles: Annual Modulation Signature: EPJC 56(2008)333, • Results on rare processes: PEP violation in Na and I: EPJC 62(2009)327 closing the Cu box housing the detectors EPJC 67(2010)39 view at end of detectors’ installation in the Cu box

Some on residual contaminants in new ULB Na. I(Tl) detectors a/e pulse shape discrimination has practically 100% effectiveness in the Me. V range e The measured a yield in the new DAMA/LIBRA detectors ranges from 7 to some tens a/kg/day a 232 Th 238 U live time = 570 h 3 232 residual contamination From time-amplitude method. If Th chain at equilibrium: it ranges from 0. 5 ppt to 7. 5 ppt First estimate: considering the measured a and 232 Th activity, if 238 U chain at equilibrium 238 U contents in new detectors typically range from 0. 7 to 10 ppt residual contamination chain splitted into 5 subchains: Thus, in this case: (2. 1± 0. 1) ppt of 2 and: (15. 8± 1. 6) Bq/kg for 4 1 238 U 234 U + 230 Th; nat. K 5 Second generation R&D for new DAMA/LIBRA crystals: new selected powders, physical/chemical radiopurification, new selection of overall materials, new protocol for growing and handling 238 U 232 Th; and 129 I/nat. I 210 Pb (0. 35 ± 0. 06) ppt for (21. 7± 1. 1) Bq/kg for residual contamination The analysis has given for the nat. K content in the crystals values not exceeding about 20 ppb 129 I 234 U 230 Th 226 Ra 210 Pb 206 Pb 226 Ra; 238 U (24. 2± 1. 6) Bq/kg for 210 Pb. double coincidences 210 Pb ≈1. 7 10 -13 for all the new detectors in the new detectors: (5 − 30) Bq/kg. No sizable surface pollution by Radon daugthers, thanks to the new handling protocols . . . more on NIMA 592(2008)297

DAMA/LIBRA calibrations Low energy: various external gamma sources (241 Am, and internal X-rays or gamma’s (40 K, 125 I, 129 I), routine calibrations with 241 Am 133 Ba) High energy: external sources of gamma rays (e. g. 137 Cs, 60 Co and 133 Ba) and gamma rays of 1461 ke. V due to 40 K decays in an adjacent detector, tagged by the 3. 2 ke. V X-rays The signals (unlike low energy events) for high energy events are taken only from one PMT Thus, here and hereafter ke. V means ke. V electron equivalent The curves superimposed to the experimental data have been obtained by simulations

Examples of energy resolutions DAMA/LIBRA ULB Na. I(Tl) NIMA 574 (2007) 83 WARP -- 1. 1 0. 55 -- XENON 100 Co-57 2. 7 XENON 10 Neon /E @ 122 ke. V = 16% 0. 93 1. 8 of the spectrum ? subtraction 2. 2 (137 Cs), 3. 1 (57 Co) XENON 10 1. 57 (137 Cs), 2. 2 (57 Co) – 7. 5 ph ZEPLIN-III ZEPLIN-II XENON 10 e/ ke V 0. 5 -1 (deduced) field not foreseen A M A /E @ 122 ke. V = 17% D AP 28 (2007) 287 2. 35 . 5 ZEPLIN-II -- /E @ 122 ke. V = 13% at zero field : 5 WARP 2. 3 l 7 PMTs 2” phe/ke. V@working field IB RA 241 Am WARP 2. 3 l un PMT 8” phe/ke. V@zero field /L liquid WARP All experiments – except DAMA – use only calibration points at higher energy with extrapolation to low energy Jo. P: Conf. Ser. 65 (2007) 012015

Infos about DAMA/LIBRA data taking • calibrations: 72 M events from sources • acceptance window eff: 82 M events ( 3 M events/ke. V) • EPJC 56(2008)333 • EPJC 67(2010)39 • First upgrade on Sept 2008: - replacement of some PMTs in HP N 2 atmosphere - restore 1 detector to operation - new Digitizers installed (U 1063 A Acqiris 1 GS/s 8 -bit High-Speed c. PCI) - new DAQ system with optical read-out installed • New upgrade foreseen on fall 2010 . . . continuously running

Model Independent Annual Modulation Result experimental single-hit residuals rate vs time and energy DAMA/LIBRA 1 -6 (0. 87 ton yr) Acos[w(t-t 0)] ; continuous lines: t 0 = 152. 5 d, T = 1. 00 y The fit has been done on the DAMA/Na. I & DAMA/LIBRA data (1. 17 ton yr) 2 -4 ke. V A=(0. 0183± 0. 0022) cpd/kg/ke. V 2/dof = 75. 7/79 8. 3 C. L. Absence of modulation? No 2/dof=147/80 P(A=0) = 7 10 -6 2 -5 ke. V A=(0. 0144± 0. 0016) cpd/kg/ke. V 2/dof = 56. 6/79 9. 0 C. L. Absence of modulation? No 2/dof=135/80 P(A=0) = 1. 1 10 -4 2 -6 ke. V A=(0. 0114± 0. 0013) cpd/kg/ke. V 2/dof = 64. 7/79 8. 8 C. L. Absence of modulation? No 2/dof=140/80 P(A=0) = 4. 3 10 -5 The data favor the presence of a modulated behavior with proper features at 8. 8 C. L.

Modulation amplitudes in 13 one-year experiments (DAMA/Na. I and DAMA/LIBRA) DAMA/Na. I (7 annual cycles: 0. 29 ton x yr) + DAMA/LIBRA (6 annual cycles: 0. 87 ton x yr) total exposure: 425428 kg day = 1. 17 ton yr A, T, t 0 obtained by fitting the single-hit data with Acos[w(t-t 0)] • The modulation amplitudes for the (2 – 6) ke. V energy interval, obtained when fixing the period at 1 yr and the phase at 152. 5 days, are: (0. 019± 0. 003) cpd/kg/ke. V for DAMA/Na. I and (0. 010± 0. 002) cpd/kg/ke. V for DAMA/LIBRA. • Thus, their difference: (0. 009± 0. 004) cpd/kg/ke. V is 2σ which corresponds to a modest, but non negligible probability. The c 2 test (c 2 = 9. 3, 12. 2 and 10. 1 over 12 d. o. f. for the three energy intervals, respectively) and the run test (lower tail probabilities of 57%, 47% and 35% for the three energy intervals, respectively) accept at 90% C. L. the hypothesis that the modulation amplitudes are normally fluctuating around their best fit values. compatibility among the annual cycles

Power spectrum of single-hit residuals (according to Ap. J. 263(1982)835; Ap. J. 338(1989)277) Treatment of the experimental errors and time binning included here 2 -6 ke. V vs 6 -14 ke. V DAMA/Na. I (7 years) DAMA/LIBRA (6 years) total exposure: 0. 29 ton yr total exposure: 0. 87 ton yr DAMA/Na. I (7 years) + DAMA/LIBRA (6 years) total exposure: 1. 17 ton yr 2 -6 ke. V 6 -14 ke. V Principal mode in the 2 -6 ke. V region: DAMA/Na. I DAMA/LIBRA 2. 737 · 10 -3 d-1 ≈ 1 y-1 2. 697 10 -3 d-1 ≈ 1 yr-1 6 -14 ke. V DAMA/Na. I+LIBRA 2. 735 10 -3 d-1 ≈ 1 yr-1 + Not present in the 6 -14 ke. V region (only aliasing peaks) Clear annual modulation is evident in (2 -6) ke. V while it is absent just above 6 ke. V

Rate behaviour above 6 ke. V • No Modulation above 6 ke. V A=(0. 3± 0. 9) 10 -3 cpd/kg/ke. V DAMA/LIBRA DAMALIBRA 1 -6 Mod. Ampl. (6 -10 ke. V): cpd/kg/ke. V (0. 0016 ± 0. 0031) DAMA/LIBRA-1 -(0. 0010 ± 0. 0034) DAMA/LIBRA-2 -(0. 0001 ± 0. 0031) DAMA/LIBRA-3 -(0. 0006 ± 0. 0029) DAMA/LIBRA-4 -(0. 0021 ± 0. 0026) DAMA/LIBRA-5 (0. 0029 ± 0. 0025) DAMA/LIBRA-6 statistically consistent with zero • No modulation in the whole energy spectrum: studying integral rate at higher energy, R 90 • R 90 percentage variations with respect to their mean values for single crystal in the DAMA/LIBRA running periods Period • Fitting the behaviour with time, adding DAMA/LIBRA-1 a term modulated with period and phase DAMA/LIBRA-2 as expected for DM particles: DAMA/LIBRA-3 DAMA/LIBRA-4 consistent with zero DAMA/LIBRA-5 DAMA/LIBRA-6 Mod. Ampl. -(0. 05 0. 19) cpd/kg -(0. 12 0. 19) cpd/kg -(0. 13 0. 18) cpd/kg (0. 15 0. 17) cpd/kg (0. 20 0. 18) cpd/kg -(0. 20 0. 16) cpd/kg 1%, fully accounted by statistical considerations + if a modulation present in the whole energy spectrum at the level found in the lowest energy region R 90 tens cpd/kg 100 far away No modulation above 6 ke. V This accounts for all sources of bckg and is consistent with studies on the various components

Multiple-hits events in the region of the signal • Each detector has its own TDs read-out pulse profiles of multiple-hits events (multiplicity > 1) acquired (exposure: 0. 87 ton yr). DAMA/LIBRA 1 -6 2÷ 4 ke. V: A = -(0. 0011 ± 0. 0007) cpd/kg/ke. V 2÷ 5 ke. V: A = -(0. 0008 ± 0. 0005) cpd/kg/ke. V 2÷ 6 ke. V: A = -(0. 0006 ± 0. 0004) cpd/kg/ke. V • The same hardware and software procedures as the ones followed for single-hit events signals by Dark Matter particles do not belong to multiple-hits events, that is: Dark Matter multiple-hits = particles events “switched off” Evidence of annual modulation with proper features as required by the DM annual modulation signature - present in the single-hit residuals - absent in the multiple-hits residual This result offers an additional strong support for the presence of Dark Matter particles in the galactic halo, further excluding any side effect either from hardware or from software procedures or from background

Energy distribution of the modulation amplitudes DAMA/Na. I (7 years) + DAMA/LIBRA (6 years) here. T=2 / =1 yr and t 0= 152. 5 day total exposure: 425428 kg day 1. 17 ton yr DE = 0. 5 ke. V A clear modulation is present in the (2 -6) ke. V, while Sm values compatible with zero are present just above The Sm values in the (6– 20) ke. V have random fluctuations around zero with 2 equal to 27. 5 for 28 d. o. f.

Is there a sinusoidal contribution in the signal? Phase 152. 5 day? DAMA/Na. I (7 years) + DAMA/LIBRA (6 years) total exposure: 425428 kg day = 1. 17 ton yr For Dark Matter signals: • |Zm| «|Sm| |Ym| • = 2 /T • t* t 0 = 152. 5 d • T = 1 year Slight differences from 2 nd June are expected in case of contributions from non thermalized DM components (as e. g. the Sag. DEG stream) E (ke. V) Sm (cpd/kg/ke. V) Zm (cpd/kg/ke. V) Ym (cpd/kg/ke. V) t* (day) 2 -6 0. 0111 ± 0. 0013 -0. 0004 ± 0. 0014 0. 0111 ± 0. 0013 150. 5 ± 7. 0 6 -14 -0. 0001 ± 0. 0008 0. 0002 ± 0. 0005 -0. 0001 ± 0. 0008 --

The analysis at energies above 6 ke. V, the analysis of the multiple-hits events and the statistical considerations about Sm already exclude any sizable presence of systematical effects Additional investigations on the stability parameters Modulation amplitudes obtained by fitting the time behaviours of main running parameters, acquired with the production data, when including a DM-like modulation Running conditions stable at a level better than 1% also in the two new running periods All the measured amplitudes well compatible with zero + none can account for the observed effect (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)

Summarizing on a hypothetical background modulation • No Modulation above 6 ke. V A=(0. 3± 0. 9) 10 -3 cpd/kg/ke. V DAMA/LIBRA • No modulation in the whole energy spectrum 1% + if a modulation present in the whole energy spectrum at the level found in the lowest energy region R 90 tens cpd/kg 100 far away • No modulation in the 2 -6 ke. V multiple-hits residual rate (green points) vs single-hit residual rate (red points) No background modulation (and cannot mimic the signature): all this accounts for the all possible sources of bckg Nevertheless, additional investigations performed. . .

The case Monte. Carlo simulation • muon intensity distribution • Gran Sasso rock overburden map events where just one detector fires Case of fast neutrons produced by Annual modulation amplitude at low energy due to modulation: @ LNGS ≈ 20 m-2 d-1 (± 2% modulated) Measured neutron Yield @ LNGS: Y=1÷ 7 10 -4 n/ /(g/cm 2) Rn = (fast n by )/(time unit) = Y Meff Sm( ) = Rn g e f. DE fsingle 2% /(Msetup DE) g = geometrical factor; e = detection effic. by elastic scattering f. DE = energy window (E>2 ke. V) effic. ; f single = single hit effic. Hyp. : Meff = 15 tons; g ≈ e ≈ f. DE ≈ fsingle ≈ 0. 5 (cautiously) Knowing that: Msetup ≈ 250 kg and DE=4 ke. V Sm( ) < (0. 4÷ 3) 10 -5 cpd/kg/ke. V Moreover, this modulation also induces a variation in other parts of the energy spectrum and in the multi-hits events It cannot mimic the signature: already excluded also by R 90, by multi-hits analysis + different phase, etc. Can (whatever) hypothetical cosmogenic products be considered as side effects, assuming that they might produce: But, its phase should be (much) • if <<T/2 : ? • only events at low energy, • only single-hit events, • no sizable effect in the multiple-hit counting rate larger than phase, t : • if >>T/2 : It cannot mimic the signature: different phase The phase of the muon flux at LNGS is roughly around middle of July and largely variable from year to year. Last meas. by LVD partially overlapped with DAMA/Na. I and fully with DAMA/LIBRA: 1. 5% modulation and phase=July 5 th 15 d. R 90, multi-hits, phase, and other analyses DAMA/Na. I + DAMA/LIBRA measured a stable phase: May, 26 th 7 days This phase is 7. 3 far from July 15 th and is 5. 9 far from July 5 th NO

Summary of the results obtained in the additional investigations of possible systematics or side reactions: (previous exposure and details see: NIMA 592(2008)297, EPJC 56(2008)333, J. Phys. Conf. Ser. 203(2010)012040 DAMA/LIBRA 1 -6 Source Main comment RADON Sealed Cu box in HP Nitrogen atmosphere, 3 -level of sealing, etc. TEMPERATURE Installation is air conditioned+ detectors in Cu housings directly in contact with multi-ton shield huge heat capacity + T continuously recorded NOISE Effective full noise rejection near threshold ENERGY SCALE Routine + instrinsic calibrations EFFICIENCIES Regularly measured by dedicated calibrations BACKGROUND No modulation above 6 ke. V; no modulation in the (2 -6) ke. V multiple-hits events; this limit includes all possible sources of background SIDE REACTIONS Muon flux variation measured at LNGS + they cannot satisfy all the requirements of annual modulation signature Cautious upper limit (90%C. L. ) <2. 5 10 -6 cpd/kg/ke. V <10 -4 cpd/kg/ke. V <1 -2 10 -4 cpd/kg/ke. V <10 -4 cpd/kg/ke. V <3 10 -5 cpd/kg/ke. V Thus, they can not mimic the observed annual modulation effect

Summarizing • Presence of modulation for 13 annual cycles at 8. 9 C. L. with the proper distinctive features of the DM signature; all the features satisfied by the data over 13 independent experiments of 1 year each one • The total exposure by former DAMA/Na. I and present DAMA/LIBRA is 1. 17 ton yr (13 annual cycles) • In fact, as required by the DM annual modulation signature: 1. The single-hit events show a clear cosine-like modulation, as expected for the DM signal 4. The modulation is present only in the low energy (2 -6) ke. V interval and not in other higher energy regions, consistently with expectation for the DM signal 2. Measured period is equal to (0. 999 0. 002) yr, well compatible with the 1 yr period, as expected for the DM signal 5. The modulation is present only in the single-hit events, while it is absent in the multiple-hits as expected for the DM signal 3. Measured phase (146 7) days is well compatible with 152. 5 days as expected for the DM signal 6. The measured modulation amplitude in Na. I(Tl) of the single-hit events in (2 -6) ke. V is: (0. 0116 ± 0. 0013) cpd/kg/ke. V (8. 9σ C. L. ). No systematic or side process able to simultaneously satisfy all the many peculiarities of the signature and to account for the whole measured modulation amplitude is available

Model-independent evidence by DAMA/Na. I and DAMA/LIBRA well compatible with several candidates in many astrophysical, nuclear and particle physics scenarios No other experiment whose result can be directly compared in model independent way with those of DAMA/Na. I and DAMA/LIBRA available Available results from direct searches using different target materials and approaches do not give any robust conflict Moreover, whatever hints from other direct searches must be interpreted; in any case large room of compatibility with DAMA is present Possible model dependent positive hints from indirect searches not in conflict with DAMA; but interpretation and the evidence itself in indirect searches depend e. g. on bckg modeling (also including pulsars, supernovae remnants, . . . ), on DM spatial velocity distribution, either on forced boost factor or on unnatural clumpiness, etc.

Example 2010 – Positive recoil-like excesses in different kinds of direct searches Ø Co. Ge. NT: Co. Ge. NT low-energy rise in the spectrum (irriducible by the applied background reduction procedures) Ø CDMS: CDMS after data selection and cuts, 2 Ge candidate recoils survive in an exposure of 194. 1 kg x day (0. 8 estimated as expected from residual background) Ø CRESST: CRESST after data selection and cuts, 32 O candidate recoils survive in an exposure of 400 kg x day (8. 7± 1. 2 estimated as expected from residual background) s ie nt i ta r e nc u e All these recoil-like excesses, if interpreted in WIMP lscenarios, are also compatible with the th l a DAMA annual modulation result g rin e Some recent literature discussing compatibility in various sid frameworks e. g. : n co • Light WIMP DM (ar. Xiv: 1003. 0014, ar. Xiv: 1007. 1005 v 2) • Light Neutralino DM (ar. Xiv: 1009. 0549) e r o • Low mass neutralino in eff. MSSM • Composite DM (ar. Xiv: 1003. 1144) m (PRD 81(2010)107302, ar. Xiv: 0912. 4025) ch • Light scalar WIMP through Higgs portal (ar. Xiv: 1003. 2595) u • Inelastic DM (PRD 79(2009)043513, ar. Xiv: 1007. 2688) m • SD Inelastic DM (ar. Xiv: 0912. 4264) d • Mirror DM (ar. Xiv: 10010096) an • Complex Scalar Dark Matter (ar. Xiv: 1005. 3328) … • Resonant DM (ar. Xiv: 0909. 2900) • DM from exotic 4 th generation quarks (ar. Xiv: 1002. 3366) • Light Neutralinos (ar. Xiv: 1003. 0682) • . . .

Some of the DM candidate particles might annihilate if certain conditions are assumed as fulfilled e+ and e- data compilation Pamela positron fraction deviates from predictions of an assumed secondary production model (GALPROP); but, analogous models also exist with different secondary production giving no significant deviation, e. g. Local measurements of cosmic ray e+/- e+/(e++e-) PAMELA Adriani et al. (2009) (e++e-) HESS and FERMI Aharonian et al. (2009), Abdo et al. (2009) Uncertainties are still large While PAMELA e + are well accounted by secondary e + expectations, a conventional secondary origin seems unlikely when FERMI data (e ++ e-) are included. • Interpretation in terms of DM particle annihilation requires a very large boost factor ( 400): i) boost the cross section, ii) play with the propagation parameters, iii) consider extra-source (subhalos, IMBHs). Unlikely + no excess is observed in the anti-proton spectrum • Other well known sources can account for a similar positron fraction (see literature): pulsars, supernova explosions near the Earth, SNR Example Therefore, no constraint on direct detection phenomenology ar. Xiv: 0809. 5268 ar. Xiv: 1002. 1910

Just few examples of interpretation of the annual modulation in terms of candidate particles in some scenarios • Not best fit • About the same C. L. WIMP: SI 100 -120 Ge. V 15 Ge. V Evans power law N. F. W. WIMP: SI & SD θ = 2. 435 100 Ge. V 15 Ge. V Evans power law N. F. W. LDM, bosonic DM m. L=0 EPJC 56(2008)333 Compatibility with several candidates; other ones are open

About model dependent exclusion plots Selecting just one simplified model and experimental aspects framework, making lots of assumptions, • marginal and “selected” exposures fixing large numbers of parameters … but… • which particle? • which couplings? which model for the coupling? • which form factors for each target material and related parameters? • which nuclear model framework for each target material? • Which spin factor for each case? • which scaling laws? • which halo profile? • which halo parameters? • which velocity distribution? • which parameters for velocity distribution? • which v 0? • which vesc? • …etc. road sign or labyrinth? , , , • Threshold, energy scale and energy resolution when calibration in other energy region (& few phe/ke. V)? Stability? Too few calibration procedures and often not in the same running conditions • Selections of detectors and of data • handling of (many) “subtraction” procedures and stability in time of all the cuts windows and related + no uncertainties accounted quantities, etc. ? Efficiencies? for • fiducial volume vs disuniformity no sensitivity to DM annual of detector response in liquids? modulation signature • Used values in the Different target materials calculation (q. f. , etc) DAMA implications often • Used approximations presented in etc. , etc. ? (see e. g. incorrect/incomplete/nonupdated way ar. Xiv: 1005. 3723 v 1, 1005. 0838 v 3, 0806. 0011 v 2, PLB 637(2006)156 …) Exclusion plots have no “universal validity” and cannot disproof a model independent result in any given general model framework (they depend not only on the general assumptions largely unknown at present stage of knowledge, but on the details of their cooking) + generally overestimated + methodological robustness (see R. Hudson, Found. Phys. 39 (2009) 174) On the other hand, possible positive hints (above an estimated background) should be interpreted. Large space for compatibility.

Upgrading DAMA/LIBRA Continuously running • Replacement of all the PMTs with higher Q. E. ones • New high Q. E. PMTs at hand • Goal: lowering the energy thresholds of the detectors • New PMTs with higher Q. E. : • Continuing data taking in the new configuration also below the present 2 ke. V energy threshold • Reaching even higher C. L. for the model independent result and highly precisely all the modulation parameters to further investigate among the many possible scenarios for DM candidates, interactions, halo models, nuclear/atomic properties, etc. . • Investigation on dark matter peculiarities and second order effect • Special data taking for other rare processes.

Nuovi PMTs dell’Hamamatsu con elevata Q. E. Sommario sviluppo e produzione nuovi PMT: • 40 PMTs prodotti, già consegnati e testati ü 20 selezionati e attualmente stoccati in galleria (<Q. E. > = 37% @ peak and dark current < 500 cps) ü 20 scartati e restituiti alla ditta • 20 PMTs prodotti e consegnati (vedi specifiche nella tabella) ü(<Q. E. > = 39. 4% @ peak and dark current << 500 cps) • 10+6 PMTs in spedizione ( entro fine Settembre)

Nuovi PMTs dell’Hamamatsu con elevata Q. E. Spectral response characteristics and Single Photon Pulse Height Distribution

Test on the new PMTs (1) Q. E. measurement of all the PMTs at the optical NEMO laboratory – Department of Physics – University of Rome “Tor Vergata”. Ø exciting sources - lamps (near UV, VIS and near IR) - lasers (Ar+, He-Ne, Nd: YAG and laser diodes), l = 630 1500 nm). Example of spectral sensitivity (m. A/W) and quantum efficiency blu lines: measurements by Hamamatsu Spectral sensitivity for a PMT as a function of the radial distance from the centre of photocathode blue curve is an empirical curve PMTs connection: i) the anode and all the dynodes were connected at +200 V ii) the photocathode connected to ground through a resistor The current of the cathode measured by a KEITHLEY electrometer mod. 6514 Q. E. measured at: 351. 7 nm, 457. 9 nm and 501. 7 nm

Test on the new PMTs (3) Measurements of the residual contamination in PMTs carried out in the LNGS Ge facility Values of residual contamination in trace very similar for all the PMTs (see Standard deviations) Dark current in best prototypes around 100 Hz (the 2 PMTs of each detector work in coincidence)

Conclusions • Positive model independent evidence for the presence of DM particles in the galactic halo at 8. 9 s C. L. (cumulative exposure 1. 17 ton yr - 13 annual cycles DAMA/Na. I & DAMA/LIBRA) • Modulation parameters determined with better precision • Full sensitivity to many kinds of DM candidates (both with high and low mass) and to many interaction types (both inducing recoils and/or e. m. radiation), many astrophysical scenarios, etc. • No experiment exists whose result can be directly compared in a model independent way with those by DAMA/Na. I & DAMA/LIBRA. • Recent recoil-like excesses claimed in direct searches above an evaluated background are - when interpreted as induced by some DM candidates - compatible with DAMA in many scenarios; null searches not in robust conflict. Consider also the experimental and theoretical uncertainties. • Indirect model dependent searches not in conflict. • Investigations other than DM what next? • Upgrade in fall 2010 substituting all the PMTs with new ones having higher Q. E. to lower the software energy threshold and improve general features. Collect a suitable exposure in the new running conditions to improve the knowledge about the nature of the particles and on features of related astrophysical, nuclear and particle physics aspects. • Investigate second order effects • R&D towards a possible 1 ton ULB Na. I(Tl) set-up experiment proposed in 1996 DAMA/LIBRA still the highest radiopure set-up in the field with the largest sensitive mass, the full controlled running conditions, the largest duty-cycle, exposure orders of magnitude larger than any other activity in the field, ecc. , and the only one which effectively exploits a model independent DM signature