Dark Matter 1-ton Era Cristiano Galbiati Princeton University - PowerPoint PPT Presentation

Dark Matter 1-ton Era Cristiano Galbiati Princeton University Milan Università degli Studi June 30, 2014

Fuchs astro-ph/9812048 WMAP 2006 200 NGC 6530 v c (km/s) 150 100 dark halo disk 50 gas 0 0 5 10 15 20 r (kpc)

Feng Has gravitational interactions Is long lived Is cold Is not baryonic

e, γ χ ,n Attisha

Figueroa-Feliciano SuperCDMS Soudan Low Threshold XENON 10 S2 (2013) 10 � 39 10 � 3 CDMS-II Ge Low Threshold (2011) PICO250-C3F8 Z-mediated scattering CDMSlite CoGeNT (2012) 10 � 40 10 � 4 (2013) CDMS Si (2013) ) 2 1 0 2 ( E 10 � 41 L 10 � 5 WIMP � nucleon cross section � cm 2 � P M ) 2 I S 1 WIMP � nucleon cross section � pb � 0 2 ( DAMA P P U O ) 2 C 1 0 2 ( I I I - N I 10 � 42 CRESST L 10 � 6 P ) 9 E 0 Z 0 2 ( e SuperCDMS G I I S M D ) 2 C 1 EDELWEISS (2011) 0 2 ( 10 � 43 0 10 � 7 0 1 n o n e SNOLAB X ) 3 1 N 0 SuperCDMS Soudan 2 E U ( X U 0 L 5 T e d 10 � 44 10 � 8 R I N i S k r a I 3 D F C O - 0 C 7 Be 5 T 2 C A T E O g O H C S n R I E R T P E N i r SuperCDMS SNOLAB Neutrinos I N G e 8 B t t 10 � 9 10 � 45 a c T 1 s n o Neutrinos n d e 2 X DEAP3600 e G t e a d i S i d k r a e D m Z L 10 � 46 - 10 � 10 H 10 � 47 10 � 11 (Green&ovals)&Asymmetric&DM&& (Violet&oval)&Magne7c&DM& G I N R E T T A C (Blue&oval)&Extra&dimensions&& Atmospheric and DSNB Neutrinos S T 10 � 48 R E N 10 � 12 H E O (Red&circle)&SUSY&MSSM& C O N I R U T E &&&&&MSSM:&Pure&Higgsino&& N 10 � 49 10 � 13 &&&&&MSSM:&A&funnel& &&&&&MSSM:&BinoEstop&coannihila7on& &&&&&MSSM:&BinoEsquark&coannihila7on& 10 � 14 10 � 50 & 1 10 100 1000 10 4 WIMP Mass � GeV � c 2 �

What Techniques • Si/Ge Bolometers • NaI Scintillating Crystals • Bubble Chambers • Noble (Xe/Ar) Scintillators • Noble (Xe/Ar) Scintillating TPC

Remember! • It only makes sense if you can guarantee background-free condition

PICO Bubble Chambers and Update on COUPP60 Hugh Lippincott, Fermilab for the PICO Collaboration UCLA DM 2014 1

Why bubble chambers? • By choosing superheat parameters appropriately (temperature and pressure), bubble chambers are blind to electronic recoils (10 -10 or better) • To form a bubble requires two things • Enough energy • Enough energy density - length scale must be comparable to the critical bubble size • Electronic recoils never cross the second threshold! 6

COUPP60 • Collected >3000 kg-days of dark matter search data between 9 and 25 keV threshold • Good live fraction > 80% (including >95% over the last month) • No darkening 22

COUPP60 - the data • Analysis still under development • Good news: Zero multiple bubbles, no neutrons. Limit on neutron rate is factor 7 below observed rate in COUPP4 • Bad news: Population of events that sound like nuclear recoils but are clearly not WIMPs • Silver lining: statistics - we can actually study them in detail • Indications confirm a slightly different acoustic distribution and similar timing and spatial correlations to COUPP4 background for at least some fraction of events 27

XMASS,&& present&and&future&development& S.&Moriyama& Kamioka&Observatory,& Ins=tute&for&Cosmic&Ray&Research,& The&University&of&Tokyo& 28 th &Feb.&2014,&Dark&MaKer&2014,&UCLA& &

&XMASS:&LXe&single&& &&&&&&&phase&detector& • Many&interes=ng&physics&targets,&including&EM&interac=ons& – Dark&maKer:&elas=c,&inelas=c& 129 Xe,&superQWIMPs,&ALP,&HP,&…& – Solar&axions,&2 ν DEC,&SN,&and&other&unexpected&signal& • Intrinsic&BG&of&XMASS&I:&O(10 Q4 )/kg/keV ee /d&@40keV& dominated&by& 214 Pb,&w/o&part.&ID&(arXiv:&1401.4737)& • Larger&size&is&advantageous.&Surf.&BG,&Kr,&&&Rn& important.& 2&

&Key&component&&&& &&&to&see&the&surface& • One&of&the&most&simple&and&straighforward&way& to&see&the&surface&events&is&the&use&of&PMTs&with& a&convex,&dome&shape&photocathode.& • Similar&shape&can&be&seen&in&many&examples. � 4& From PMT handbook (HPK) �

&Iden=fica=on& BG generated position &&&performance& Hit position (photocathode) � • 3&PMTs&accept&40Q50%&of&total& • One&example&of&surface&ID:& &&&3&PMTs&>&10%&of&total&PE& surface � 2-2.5keVee • Assume&surface&RI&8mBq& 210 Pb,& 42yrs equiv. � &&&10 7 &events&~42y.&In&2Q2.5keV ee& &&&&0.1&events/y&w/o&dead&tube& &&&&0.3&events/y&w/&15&dead&tubes& • DM&signal&efficiency&&~&20%&of&all&volume.& Surface events can be identified and rejected effectively. � 6&

&Beyond&the&surface:& &&&solar&pp ν ,&Kr&and&Rn& • Internal&background,&future&goal&<10 Q5 /kg/keV ee /d& – e&scat.&by&solar&pp& ν &~&10 Q5 /kg/keV ee /d& ! &irreducible& – 212 Pb,&<0.3 µ Bq/kg&~&10 Q5 /kg/keV ee /d=dru& ! &1/10& – 85 Kr&(Q β =687keV,& τ 1/2 =11yr),&1ppt&~10 Q5 dru& ! &1/10& – 214 Pb,&10mBq/kg&~&10 Q4 dru& ! &<1/10& • γ &ray&and&neutron&contribu=on&will&be&evaluated.& • Predic=on&of&these&background&are&accurate&and&& will&be&taken&into&account&in&analyses&to&search&for&& DM&signal.&<~10 Q46 cm 2 &would&be&searched&for.& 7&

XMASS&in&future � XMASS-II � XMASS-I � XMASS-1.5 � DM DM, solar, ββ& 1ton FV (5ton) DM 10ton FV 100kg FV (800kg) 1.5m φ , ~1000 PMTs Detailed study of DM 0.8m φ , 642 PMTs Requesting budget pp solar ν& 2007- DM, pp solar ν ββ ~30meV(IH) � To discover DM � ~10 -46 cm 2 Annual/spectral info. � 10&

Dark-matter Experiment using Argon Pulse Shape Discrimination Fabrice Retière on behalf of the DEAP collaboration

DEAP-3600 concept � Liquid Argon Ball for � 3.6 tonnes of liquid dark matter search Argon o 1 ton Ar fiducial o Enclosed in 85 cm radius acrylic ball � 85 cm radius o 255 PMTs o 1 tonne fiducial � No charge readout � Excluding surface events � Scintillation only o Being installed � Start of operation early o Aka single phase 2014 o Light viewed by 255 photo-multiplier tubes Feb 28th, 2014 2

Neutron background mitigation � Sited at SNOLAB o 6000 meter water Liquid Argon equivalent � Inside a water tank � ~50cm of light guide acrylic and filler blocks � Ultra-low radioactivity acrylic Water TPB wavelength shifter Acrylic vessel Filler block Acrylic light guide PMT Feb 28th, 2014 3

Pulse shape discrimination concept Nuclear Recoil Tagged AmBe source Background ( �� Feb 28th, 2014 7

Projected backgrounds Assuming 8PE per keV Background Rate/count Mitigation Neutron < 2 pBq/kg Shielding: 6000 mwe (SNOLAB), Active water In 1t LAr < 0.06 count/year shield, light guides and filler blocks Material selection � & � < 2 pBq/kg Pulse shape discrimination Material selection (for � ) In 1t LAr < 0.06 count/year Radon < 1.4 nBq/kg Material selection, SAES getter, In 1t LAr < 44 count/year* cold charcoal radon trap * High energy events, not in ROI Surface �� < 0.2 mBq/m 2 Material selection (acrylic), sanding of In 1t LAr < 0.6 count/year AV (1mm removal), fiducialization. Total of <0.6 events in ROI in 3 years for a spin-independent WIMP-nucleon cross section sensitivity of 10 -46 cm 2 at 100GeV. Feb 28th, 2014 11

Challenge for Scintillating Detectors ARTICLE IN PRESS Nuclear Instruments and Methods in Physics Research A 568 (2006) 700–709 www.elsevier.com/locate/nima Time and space reconstruction in optical, non-imaging, scintillator-based particle detectors C. Galbiati, K. McCarty � a Physics Department, Princeton University, Princeton, NJ 08544, USA Received 22 April 2005; received in revised form 25 July 2006; accepted 29 July 2006 Available online 24 August 2006

Challenge for Noble Scintillators t.o.f.: ∂ x = c σ 3 n N diffusive propagation: ∂ x = R 3 2 N

Scintillating Noble TPCs ∂ z ≈ 1 mm ( ) ≈ 1 − 3 cm ∂ x , y

L U How a two-phase Xe TPC is a perfect way to look for WIMPs T. Shutt Case Western Reserve University 1 T. Shutt - NygrenFest, May 3, 2014 1