Enectalí Figueroa-Feliciano

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1 School and Workshop on Dark Matter and Neutrino Detection Dark Matter Direct Detection Lecture 3 Enectalí Figueroa-Feliciano!113

2 Outline Lecture 1: The dark matter problem WIMP and WIMP-like DM detection Lecture 2: WIMP detection technologies Current and future limits Lecture 3: Lecture 4: The SuperCDMS Experiment mev - 1GeV direct detection Lecture 5: Indirect sterile neutrino detection More DM detection technologies To the Neutrino Floor, and beyond!!114

3 Last Time: Low Mass Region Dark Matter-nucleon σsi [cm 2 ] NEWS-G Color Center (H) Color Center (O) CYGNUS HD-10 4 He BubWat EDELWEISS-III DAMIC-1K (2020) CRESST-II CRESST 1000kgd Si HV Ge HV CDMSlite R2 CDEX Dark Matter Mass [GeV/c 2 ] NEWS-G DAMIC CDEX Dark Matter-nucleon σsi [pb]!115

4 PICO Bubble Chamber: Superheated Liquids! See next talk by Andrew Sonnenschein!116

5 PICO Bubble Chamber: SD and SI limits! See next talk by Andrew Sonnenschein!117

6 CCD-based DM Search!118

7 CCD-based DM Search See talks by Juan Estrada!119

8 Directional Detection!120

9 Directional Detection!121

10 Directional Detection: Non-TPC From Kentaro Miuchi s talk at IDM!122

11 Directional Detection: TPC From Kentaro Miuchi s talk at IDM!123

12 Directional Detection: TPC From Kentaro Miuchi s talk at IDM!124

SNOLAB) Xenon Bubble Chamber Directional Detection Experiments DRIFT, DMTPC, NEWAGE,

13 Review of other Nuclear Detection Technologies Silicon CCDs: DAMIC & Sensei Bubble Chamber Experiments PICO and COUPP Excellent SD Sensitivity (currently running at SNOLAB) Xenon Bubble Chamber Directional Detection Experiments DRIFT, DMTPC, NEWAGE, MIMAC New Ideas DNA and/or organic detectors? Molecular dissociation / inelastic collisions?!125

14 Neutrino Backgrounds!126

15 Low-energy ν Interactions Elastic Quasi-Elastic e Ν e p n n p Charged W W W Current Ν e e Ν e e Ν e e For νe and ν e IBD νμ, ντ not low-e e e Neutral Current Z Ν Ν Ν Ν For all ν flavors!127

16 Low-Energy Neutrino Cross Sections Cross -2 D νe CCQE CEνNS νe CCQE (IBD) n e N Æ n e N n e p Æ e + n n e n Æ e - p n e e - Æ n e e - n e e - Æ n e e - n m e - Æ n m e - n m e - Æ n m e - m n = m B Neutrino

17 Neutrino Sources for Dark Matter Detectors Solar (νe) Diffuse Supernova Neutrino Background (all flavors) Atmospheric (all flavors) Geothermal ( ν e) Reactor ( ν e) Internal (ββ decays, ν e) Supernova (burst, so not really a background, all flavors)!129

18 Solar Neutrino pp Chain!130

19 Diffuse Supernova Background Mostly from Core Collapse Supernovae Horiuchi 2009!131

20 Atmospheric Neutrinos From Cosmic Ray interaction in atmosphere. Battistoni 2009!132

21 Geoneutrinos and Reactor Neutrinos Geoneutrinos are plentiful, but too low energy and are thus subdominant to the Solar ν flux. Reactors νs can are only important if physically close to a reactor, so we can safely ignore them. Enomoto 2005 Monroe 2007!133

22 Neutrino Sources: Solar, Atm, DSNB dn Neutrino Flux [cm -2.s -1.MeV -1 ] de Bahcall 2005 Keil 2003 Honda Neutrino Energy [MeV] pp pep hep 7Be 384.3keV 7Be 861.3keV 8B 13N 15O 17F dsnbflux 8 dsnbflux 5 dsnbflux 3 AtmNu e AtmNu ebar AtmNu mu AtmNu mubar!134

23 Coherent Elastic ν-nucleus Scattering (CEνNS) ' 4m2 r o atomic mass fa2 m r = m m N coupling constant m + m N = reduced mass Same type of process occurs with neutrinos: d N Z(1 4 sin 2 W ) 2 M A T Ν Ν dt = G2 F 4 1 2E 2 F (Q 2 ) 2 Dark Matter detectors are getting good enough to be sensitive to this signal!!135

24 CEνNS Cross Sections 2 evnr -1 D E : 7 MeV 40 MeV 200 MeV Xe, E n =7MeV Ge, E n =7MeV Ar, E n =7MeV Xe, E n =40MeV Ge, E n =40MeV Ar, E n =40MeV Xe, E n =200MeV Ge, E n =200MeV Ar, E n =200MeV Recoil

25 Neutrino CEνNS Recoil Spectrum Event rate [(ton.year.kev) -1 ] WIMP signal: m χ = 6 GeV/c 2, σ χ-n = 4.4x10-45 cm 2 pp pep hep 7Be 384.3keV 7Be 861.3keV 8B 13N 15O 17F dsnbflux 8 dsnbflux 5 dsnbflux 3 AtmNu e AtmNu ebar AtmNu mu AtmNu mubar total dr dt = Z E min dn d de dt de Recoil energy [kev]!137

26 Fitting the 8B CEνNS Signal As Dark Matter 12 C O F Si Ar Ca Ge I Xe W The reconstructed parameters are target dependent 11 WIMP mass [GeV/c 2 ] SI: o ' 4m2 r fa2 atomic mass coupling constant Target number of nucleons (A)!138

27 Fitting the 8B CEνNS Signal As Dark Matter C O F Si Ar Ca Ge I Xe W The reconstructed parameters are target dependent They also depend on the assumed interaction SD: mechanism o = Nuclear Angular Momentum WIMP-nucleon cross section [cm 2 ] 32(J + 1) G 2 m r = m m N J F m 2 r (a p hs p i + a n hs n i) 2 m + m N Fermi constant Coupling constant Spin Target number of nucleons (A) SI SD p SD n!139

28 Fitting the Individual CEνNS Signals As Dark Matter ] 2 WIMP-nucleon cross section [cm We can map where each neutrino component would land on the WIMP SI cross section - mass plane Individual Fits for a Xe Target with Zero Treshold pp pep hep 7Be_384.3keV 7Be_861.3keV 8B 13N 15O 17F dsnbflux_8 dsnbflux_5 dsnbflux_3 AtmNu_e AtmNu_ebar AtmNu_mu AtmNu_mubar ] -1 Event rate [(ton.year.kev) Nuclear form factor prevents WIMP mass determination -1 for at high masses pp pep hep 7Be_384.3keV 7Be_861.3keV 8B 13N 15O 17F dsnbflux_8 dsnbflux_5 dsnbflux_3 AtmNu_e AtmNu_ebar AtmNu_mu AtmNu_mubar Total Recoil energy [kev] WIMP mass [GeV/c ] 3!140

29 Fits to the Entire Neutrino Background as WIMPs -1 ] Event rate [(ton.year.kev) Ge Target Total neutrino background Threshold: 1 ev Threshold: 10 ev Threshold: 100 ev Threshold: 1 kev Threshold: 2.5 kev Threshold: 5 kev Threshold: 7.5 kev Threshold: 10 kev Recoil energy [kev] 2!141

30 The Neutrino Floor NEWS-G 10-2 Dark Matter-nucleon σsi [cm 2 ] Neutrino Background CRESST-II CDMSlite R2 DAMIC CDEX-10 XENON1T PICASSO PICO-60 DarkSide-50 PandaX-II, 54 ton-d DEAP Dark Matter-nucleon σsi [pb] F. Ruppin, J. Billard, EFF, L. Strigari: Dark Matter Mass [GeV/c 2 ]!142

31 WIMP Discovery Limit To asses the discovery potential of WIMP searches, we define the WIMP Discovery Limit Definition of WIMP Discovery Limit: If the true WIMP model lies above this limit, then a given experiment has a 90% probability to obtain at least a 3σ detection of the signal. We want to gauge the significance of an excess in our data from the expected neutrino background, so we define a likelihood function: ν Flux L ( n, ~ )= e (µ + Number of Number of WIMP events ν events P n j=1 µj ) NY 2 WIMP nuclear recoil energy distribution 4µ f (E ri )+ n X ν nuclear recoil energy distribution 3 µ j f j (E ) 5 ri n Y ν flux uncertainty distribution L i ( i ) WIMP cross section N! i=1 j=1 i=1 Using a likelihood ratio test, we determine what cross section of WIMPs would be detected at 3σ or better 90% of the time!143

32 Formally, there is no Neutrino Floor Be 8 B hep DSNB Atm SI WIMP-nucleon cross section [cm 2 ] Idealized Xe Experiment with no other backgrounds and 3 ev threshold 0.01 ton-year 0.1 ton-year 1 ton-year 10 ton-year 10 2 ton-year 10 3 ton-year 10 4 ton-year 10 5 ton-year 10 6 ton-year SI WIMP-nucleon cross section [pb] WIMP mass [GeV/c 2 ]!144

33 Saturation around 6 GeV WIMP Mass from 8 B ν Exposure (ton-year) 1e SI discovery limit at 6 GeV/c 2 [cm 2 ] /MT 1/ MT SuperCDMS SNOLAB Saturation Regime 1% 2% 5% 10% 15% 20% Uncertainty in Neutrino Fluxes Precision Regime Threshold and Efficiency Dependent Number of expected 8 B neutrino events!145

34 Formally, there is no Neutrino Floor Be 8 B hep DSNB Atm SI WIMP-nucleon cross section [cm 2 ] Idealized Xe Experiment with no other backgrounds and 3 ev threshold 0.01 ton-year 0.1 ton-year 1 ton-year 10 ton-year 10 2 ton-year 10 3 ton-year 10 4 ton-year 10 5 ton-year 10 6 ton-year SI WIMP-nucleon cross section [pb] WIMP mass [GeV/c 2 ]!146

35 Saturation above 100 GeV WIMP Masses from Atm ν SI discovery limit at 100 GeV/c 2 [cm 2 ] Threshold and Efficiency Dependent Exposure (ton-year) /MT 5% LZ 1/ MT G3 Saturation Regime G4? 10% 15% 20% 25% 30% Uncertainty in Neutrino Fluxes Saturation will happen for all WIMP masses above about 100 GeV Precision Regime Number of expected atmospheric neutrino events!147

36 Formally, there is no Neutrino Floor SI WIMP-nucleon cross section [cm 2 ] Be 8 B hep DSNB Atm. Idealized Xe Experiment with no other backgrounds and 3 ev threshold G2-Low Mass G3-Low Mass 0.01 ton-year 0.1 ton-year 1 ton-year 10 ton-year 10 2 ton-year 10 3 ton-year 10 4 ton-year 10 5 ton-year 10 6 ton-year G2-High Mass G3-High Mass SI WIMP-nucleon cross section [pb] WIMP mass [GeV/c 2 ]!148

37 The WIMP Discovery Limit The curve we publish in our papers is constructed from two separate calculations, one at low mass and one at high mass. The low mass threshold is set to get no pp neutrino events The high mass threshold is set to get no 8 B events The curve is not a sensitivity curve! Reiterating the definition: If the true WIMP model lies above this limit, then a given experiment has a 90% probability to obtain at least a 3σ detection of the signal. F. Ruppin, J. Billard, EFF, L. Strigari: !149

38 WIMP Discovery Limit for Different Targets Spin Independent Interaction SI WIMP-nucleon cross section [cm 2 ] Xe Ge Ar Si DAMIC CDMSLite (2013) SuperCDMS - LT (2014) CDMS Si (2013) CRESSTDAMA EDELWEISS (2011) WIMP mass [GeV/c 2 ] SIMPLE (2012) COUPP (2012) ZEPLIN-III (2012) CDMS II Ge (2009) Xenon100 (2012) LUX (2013) WIMP-nucleon cross section [pb]!150

39 WIMP Discovery Limit for Different Targets Spin Independent Interaction SI WIMP-nucleon cross section [cm 2 ] DAMIC CDMSLite (2013) CaWO 4 CF 3 I CF 3 I with energy C 3 F 8 C 3 F 8 with energy SuperCDMS - LT (2014) CDMS Si (2013) CRESSTDAMA EDELWEISS (2011) WIMP mass [GeV/c 2 ] SIMPLE (2012) COUPP (2012) ZEPLIN-III (2012) CDMS II Ge (2009) Xenon100 (2012) LUX (2013) WIMP-nucleon cross section [pb]!151

WIMP Discovery Limit for Different Targets SD (proton) WIMP-nucleon cross section [cm 2 ] 10-34 10-36 10-38 10-40 10-42 10-44 10-46 Spin Dependent Interaction CF 3 I CF 3 I with energy C 3 F 8 C 3 F

40 WIMP Discovery Limit for Different Targets SD (proton) WIMP-nucleon cross section [cm 2 ] Spin Dependent Interaction CF 3 I CF 3 I with energy C 3 F 8 C 3 F 8 with energy arxiv: WIMP mass [GeV/c 2 ] CDMS II Ge ( ) PICASSO (2009) COUPP (2011) Xenon100 (2013) SIMPLE (2011) WIMP-nucleon cross section [pb]!152

41 Electron Recoil Backgrounds from Neutrinos Baudis 2012, Schumann 2015!153

42 Low-energy ν Interactions Elastic Quasi-Elastic e Ν e p n n p Charged W W W Current Ν e e Ν e e Ν e e For νe and ν e IBD νμ, ντ not low-e e e Neutral Current Z Ν Ν Ν Ν For all ν flavors!154

43 Low-Energy Neutrino Cross Sections Cross -2 D CEνNS νe CCE n e N Æ n e N n e p Æ e + n n e n Æ e - p n e e - Æ n e e - n e e - Æ n e e - n m e - Æ n m e - n m e - Æ n m e - m n = m B Neutrino Cross Section is 10,000 times smaller than CNS But you get a much higher recoil due to the small mass of the electron. Thus pp and 7 Be will dominate at 10 kevee recoil!155

44 Electron Recoil Backgrounds 99.5% rejection cut 8.9% 136 Xe Baudis 2012!156

45 Adding both NC and CC interactions 8Bν Schumann arxiv: !157

46 Comparison between Exposure and Sensitivity CC Elastic Scattering changes the sensitivity, but not dramatically Schumann arxiv: !158

47 Strategies to Push Beyond the Neutrino Floor!159

48 Target Complementarity The reconstructed parameters are target dependent SI: o ' 4m2 r fa2 coupling constant atomic mass Maybe we can eliminate the saturation regime using data from SD: o = 32(J + 1) J G 2 F m 2 m r (a r = p hs m p i + m an n hs n i) 2 m + m N various targets? Nuclear Angular Momentum Fermi constant Coupling constant Spin WIMP mass [GeV/c 2 ] C O F Si Ar Ca Ge I Xe W WIMP-nucleon cross section [cm 2 ] C O F Si Ar Ca Ge I Xe SI SD p SD n W Target number of nucleons (A) Target number of nucleons (A)!160

49 Target Complementarity: Spin Independent For Spin Independent Interactions, there is little SI WIMP-nucleon cross section [cm 2 ] gain from combining different experimental results Xe Xe+Ge Xe+Ge+Si Xe+Ge+Si+C 3 F 8 Xe+Ge+Si+C 3 F 8 -with-energy WIMP Discovery Limit 1 10 WIMP mass [GeV/c 2 ] sensitivity Xe sensitivity Xe+Ge sensitivity Xe+Ge+Si sensitivity Xe+Ge+Si+C 3 F 8!161

50 Target Complementarity: Spin Dependent For Spin Dependent Interactions, there is some SD (proton) WIMP-nucleon cross section [cm 2 ] gain from combining different experimental results Xe Xe+Ge Xe+Ge+Si Xe+Ge+Si+C 3 F 8 Xe+Ge+Si+C 3 F 8 -with-energy C 3 F 8 Xe C3F8 C3F8 + Xe + Ge + Si 1 10 WIMP mass [GeV/c 2 ] C 3 F 8 -with-energy sensitivity Xe sensitivity Xe+Ge sensitivity Xe+Ge+Si sensitivity Xe+Ge+Si+C 3 F 8 sensitivity C 3 F 8!162

Directional Detectors and the Neutrino Background We see a dark matter wind in the laboratory due to the motion of the solar system in the Galaxy.

51 Directional Detectors and the Neutrino Background We see a dark matter wind in the laboratory due to the motion of the solar system in the Galaxy. This wind changes apparent direction in the lab frame due to the diurnal rotation of the Earth The direction of the dark matter wind does not overlap with the position of the Sun in the sky, and thus the direction of solar neutrinos is always different than the dark matter wind. We can use this to differentiate dark matter signals from neutrino backgrounds! C.A.J. O'Hare, A.M. Green, J. Billard, EFF, L.E. Strigari, arxiv: !163

52 Directional Detectors and the Neutrino Background Maximum DM- Sun Separation (120 o ) Minimum DM-Sun Separation (60 o ) C.A.J. O'Hare, A.M. Green, J. Billard, EFF, L.E. Strigari, arxiv: !164

53 Directional Detectors and the Neutrino Background Directional Detectors can keep dark matter searches background free from solar neutrinos (note in this study we ignored other backgrounds!) Atmospheric Neutrinos look isotropic to directional detectors, and thus still form an irreducible background The technology to perform directional detector searches at these exposures is not yet at hand, but this study motivates their continued development 1 MT 1 MT C.A.J. O'Hare, A.M. Green, J. Billard, EFF, L.E. Strigari, arxiv: !165

54 The Neutrino Floor will be a hard wall for a while NEWS-G 10-2 Dark Matter-nucleon σsi [cm 2 ] CRESST-II Neutrino Background CDMSlite R2 DAMIC CDEX-10 XENON1T PICASSO PICO-60 DarkSide-50 PandaX-II, 54 ton-d DEAP Dark Matter-nucleon σsi [pb] F. Ruppin, J. Billard, EFF, L. Strigari: Dark Matter Mass [GeV/c 2 ]!166

55 End of Lecture 3!167

Status of DM Direct Detection. Ranny Budnik Weizmann Institute of Science

Status of DM Direct Detection. Ranny Budnik Weizmann Institute of Science Status of DM Direct Detection Ranny Budnik Weizmann Institute of Science DM evidence on one slide Thermal freeze out of dark matter in the standard cosmological model Weakly Interacting Massive Particles