Neutrinos, Dark Matter and Astroparticle Physics

A.L. Hallin, University of Alberta Astbury Symposium, April 2015 Astroparticle Physics

• During the past few decades, we have established two very successful theories: Standard Model of Particle Physics, and the Standard Cosmological Model • The two models overlap, but not without tension, in the field of Astroparticle Physics. • Canada has become an internationally recognized leader in the field. • The neutrino is a well established particle, but with only partially known astrophysical significance. • Dark Matter and Matter-antimatter asymmetry are well established astrophysical phenomena but require unknown particle physics. • Dark Energy

Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin Astroparticle physics is summarized neatly by the study Connecting Quarks with the Cosmos: Eleven Science Questions for the New Century

– 1. What is the dark matter? ◄SNOLAB – 2. What is the nature of the dark energy? – 3. How did the universe begin? ◄SNOLAB – 4. Did Einstein have the last word on gravity? – 5. What are the masses of the neutrinos, and how have they shaped the evolution of the universe? ◄ SNO, SNOLAB – 6. How do cosmic accelerators work and what are they accelerating? – 7. Are protons unstable? – 8. Are there new states of matter at exceedingly high density and temperature? – 9. Are there additional spacetime dimensions? – 10. How were the elements from iron to uranium made? ◄ SNOLAB – 11. Is a new theory of matter and light needed at the highest energies? • A specific element of the third question is: – 3b. Why is the Universe made of matter and not antimatter and how did this – asymmetry arise? ◄ SNOLAB • and a related element of the tenth question is: – 10b. What role do neutrinos play in supernova explosions and how does this process affect the synthesis of heavy elements? ◄ SNOLAB

Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin SNO/SNOLAB Timeline

• 1991: SNO secured funding, started construction • 1999: Start commissioning • 2001: First results • 2004: SNOLAB CFI Excavation Starts • 2009: DEAP/SNO+ CFI grant awarded • 2012: SNOLAB grand opening • 2015: DEAP commissioning

Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin SNO

Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin Solar Fusion Chain

Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin “Solar Neutrino Problem”

Solar Fluxes: Bahcall et al Experiment vs Solar Models

1970 - 2001

Does the small number of neutrinos detected arise from

Neutrino Flavor AlanChange Astbury Symposium, or Solar University of Model Effects? Victoria, April 2015 A.L. Hallin Sudbury Neutrino Observatory

1000 tonnes

D2O Support Structure for 9500 PMTs, 60%12 m coverage Diameter Acrylic Vessel 1700 tonnes Inner Shielding5300 tonnes H2O Outer

Shield H2O Urylon Liner and Alan Astbury Symposium, University of Radon Seal Victoria, April 2015 A.L. Hallin Neutrino-Electron Scattering (ES) Sudbury Neutrino Observatory

Charged Current (CC) 1000 tonnes

D2O Support Structure for 9500 PMTs, 60%12 m coverage Diameter Acrylic Vessel

Neutral1700 Current tonnes (NC) Inner Shielding5300 tonnes H2O Outer

Shield H2O Urylon Liner and Alan Astbury Symposium, University of Radon Seal Victoria, April 2015 A.L. Hallin Three Phases of SNO: 3 NC reactions

 Phase I: Just D2O: neutron capture on deuterium • Simple detector configuration, clean measurement • Low neutron sensitivity • Poor discrimination between neutrons and electrons

Phase II: D2O + NaCl: neutron capture on Chlorine • Very good neutron sensitivity • Better neutron electron separation

3 • Phase III: D2O + He Proportional Counters • Good neutron sensitivity • Great neutron/electron separation

Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin Observables

Photomultiplier tube -position -time -charge

Reconstructed event -vertex -direction -energy -isotropy

Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin LowSignal EnergyExtraction Fit Threshold(Signal PDFs) Analysis

Not used

Teff (MeV) cosqsun

3 (R/RAV) 1 D projections

Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin 106 ν/cm2/s 106 ν/cm2/s 10-5 eV2 degrees

Null Paper Date Citation Φve σstat σsyst Hyp. Φ8B σstat σsyst Δm2 σ Θ σ 2(N-D)/(D+N) Rej σ

"Elastic Scattering Paper" Aug-01 PRL87, 071301 1.75 0.07 0.12 3.3 5.44 0.99 0.00

"Neutral Current Paper" Jul-02 PRL89,011301 1.76 0.05 0.09 5.3 5.09 0.44 0.47

0.14 0.06 0.015 "Day Night Paper" Jul-02 PRL89,011302 0.07 0.049 0.013

"Salt Paper" May-04 PRL92,181301 5.21 0.27 0.38 7.10 0.90 32.50 2.40

"Long Salt Paper" Nov-05 PRC72,05502 1.68 0.06 0.09 4.94 0.21 0.36 8.00 0.50 33.90 2.30

“Long D2O Paper” Apr-07 PRC75,045502 1.76 0.05 0.09 0.07 0.049 0.013

"NCD Paper" Sep-08 PRL101,111301 5.54 0.32 0.35 7.59 0.20 34.40 1.30

LETA Paper May-10 PRC81,055504 5.14 0.16 0.13 7.59 0.20 34.06 1.00

Long NCD Paper Jan-13 PRC87,015502 5.54 0.32 0.35 7.59 0.20 34.40 1.25

Three Phase Aug-13 PRC88,025501 5.25 0.16 0.11 7.46 0.20 33.60 0.82 Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin 6 2 6 2 -5 2 10 ν/cm /s 10Uncertaintiesν/cm /s 10 oneV 8B Neutrinodegrees Flux Null1200000 Paper Date Citation Φve σstat σsyst Hyp. Φ8B σstat σsyst Δm2 σ Θ σ 2(N-D)/(D+N)

Rej1000000 σ

800000 "Elastic Scattering 600000 Paper" Aug-01 PRL87, 071301 1.75 0.07 0.12 3.3 5.44 0.99 0.00 Statistical

400000 Systematic

"Neutral Current Flux (nus/cm**2/s) Paper" Jul-02 PRL89,011301 1.76 0.05 0.09 5.3 5.09 0.44 0.47 200000

0.14 0.06 0.015 0 "Day Night Paper" Jul-02 PRL89,011302 Jul-98 Apr-01 Jan-04 Oct-06 Jul-09 Apr-12 Dec-140.07 0.049 0.013 Date of Publication "Salt Paper" May-04 PRL92,181301 5.21 0.27 0.38 7.10 0.90 32.50 2.40

"Long Salt Paper" Nov-05 PRC72,05502 1.68 0.06 0.09 4.94 0.21 0.36 8.00 0.50 33.90 2.30

“Long D2O Paper” Apr-07 PRC75,045502 1.76 0.05 0.09 0.07 0.049 0.013

"NCD Paper" Sep-08 PRL101,111301 5.54 0.32 0.35 7.59 0.20 34.40 1.30

LETA Paper May-10 PRC81,055504 5.14 0.16 0.13 7.59 0.20 34.06 1.00

Long NCD Paper Jan-13 PRC87,015502 5.54 0.32 0.35 7.59 0.20 34.40 1.25

Three Phase Aug-13 PRC88,025501 5.25 0.16 0.11 7.46 0.20 33.60 0.82 Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin There has been remarkable progress in understanding neutrinos

Additional CP Phases for Majorana Neutrinos 

o q13 17

We have also measured Value CP? 22 mm12 and 23 CP Violation in Neutrino Sector?

Leptogenesis & Matter-Antimatter Asymmetry in the Universe?

Neutrinos have emerged as among Are Neutrinos their own the most effective probes into the nature of Antiparticles? higher unification, its symmetries and mass scales Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin Direct detection of Dark Matter

Gravitational Rotation Curves Bullet Cluster

Pink=Normal Matter (X-ray image of gas)

Blue=Mass (Gravitational Lensing)

Credit: X-ray: NASA/CXC/CfA/M.Markevitch et al.; Optical: NASA/STScI; Magellan/U.Arizona/D.Clowe et al.; Lensing Map: NASA/STScI; ESO WFI; Magellan/U.Arizona/D.Clowe et al. Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin SNOLAB

Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin DEAP-3600 Dark Matter Search

Liquid Argon for DM (Single-phase) Project Overview

3.6 tonnes liquid argon in ultraclean acrylic 40Ar vessel, 255 8-inch HQE PMTs c 40Ar c 1 tonne fiducial mass designed for < 0.2 background events/year Scattered nucleus (several 10’s of keV) is detected via scintillation in LAr 10-46 cm2 sensitivity for ~100-GeV WIMP with 3- year exposure Good Pulse-shape discrimination between b/g and nuclear recoils with scintillation

Argon is easy to purify

Very large target masses possible, no absorption of UV scintillation photons in argon, no pileup until beyond tonne-scale

Position reconstruction based on photon detection allows mitigation of backgrounds from surfaces DEAP-3600 Detector 3600 kg argon target (1000 kg fiducial) in sealed ultraclean Acrylic Vessel

Vessel is “resurfaced”in-situ to remove deposited Rn daughters after construction TPB coating for wavelength shifting

255 Hamamatsu R5912 HQE PMTs 8-inch (32% QE, 75% coverage)

50 cm light guides + PE shielding provide neutron moderation

Steel Shell immersed in 8 m water shield at SNOLAB

DEAP-3600 Dark Matter Search

40Ar c 40Ar c

Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin Fabrication and Assay of DEAP Acrylic

• Fabrication from pure MMA monomer at RPTAsia (Thailand), strict control of radon exposure for all steps • DEAP Collaborators present during fabrication • Control to < 10-20 g/g 210Pb from radon exposure • Developed system to vaporize and assay large quantities of acrylic (10 kg samples), count residue with Ge well detector for 210Pb peak, and with alpha counter for 210Po; (Corina Nantais M.Sc. Thesis)

Monomer cast at RPT AsiaAlan Astbury Symposium, ThermoformedUniversity of Panel at RPT Colorado Victoria, April 2015 A.L. Hallin Thermoforming sheets for DEAP Acrylic Vessel Reynolds Polymer, Colorado

Thermoforming tool Successfully thermoformed panel

• Thickness/radius of curvature ratio larger than had been attempted • R&D contract with Reynolds Polymer to develop thermoforming technique • Special mold/stamping tool designed and fabricated • R&D Completed early 2012 Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin Boulay IDM 2012 AV Fabrication (RPT Colorado and University of Alberta) 2011 to present

Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin AV Neck Bond (Reynolds Polymer, Tech. (RPT) at SNOLAB Jan 2013)

Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin Vessel sealed and purged, approx. 50 LGs bonded (September 2013)

Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin Bonded underground, finish machined and then light guides attached:

November, 2013

Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin DEAP-3600 Acrylic Vessel Resurfacer Removes ~1 mm acrylic in-situ after construction

Radon-scrubbed N2 purge gas and UPW flushing to extract residue

Surface contamination returns to bulk purity level

24% uniformityAlan Astburydemonstrated Symposium, University of Victoria, April 2015 A.L. Hallin 4p TPB (Organic WLS) deposition source developed for DEAP-3600

Alan Astbury Symposium, University of 20-inch test vessel, 1/3 scaleVictoria, April 2015 A.L. Hallin Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin Liquid Argon Target Transfer

2x240L Bulk LAr storage on surface LN -cooled storage dewar (transfer) 2 underground

(RGA scan underground, first transfer March 3, 2015) 38Ar (0.07%) 40Ar (99.6%) < ~ppm impurities 36Ar (0.37%) DEAP-3600 Argon Cooling System

Commissioning at 86K, June 11 2014 LN2 system operating with cryogen since June 2014 Electronics/DAQ

Front End Computers

CAEN V1720/V1740 Digitizers

Digital Trigger Module

Signal conditioning boards

Cables from PMTs

Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin Deap Status o DEAP-3600 detector assembly completed, currently completing wavelength shifter coating. Detector will have1000-kg fiducial liquid argon with < 0.2 background events/year background budget

o Extensive backgrounds and assay program, in particular ultralow background acrylic inner vessel and low radon emanation inner detector and purification system

o 10-46 cm2 sensitivity for 100-GeV WIMP

• 780 tonnes of liquid scintillator as active volume – Can be loaded with double beta decay isotope • ~9500 PMTs • 1500 + 5300 tons ultra-pure water shielding • 6800’ underground in SNOLAB

Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin Image courtesy National Geographic Detection Principle

• Organic scintillator (LAB + PPO) produces light when excited by charged particles • ~10,000 photons/MeV, of which a few hundred photons/MeV are detected by the PMTs – Can detect events depositing < 50 keV • Calorimetric measurement + pulse shape – Event energy from number of photons – Event position from photon time-of-flight

Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin Neutrino Detection

• Neutrinos interact via elastic scattering with electrons • Sensitive to all neutrino species, but cross section is 4-7 times larger for ve than vμ,τ • Detect scintillation from the recoiling electron

- e ve

±± - ve WW e

- vx e

0 - vx Z e

Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin Central Challenge: Backgrounds

Internal Radioactivity traces of radioisotopes (U/Th chain, 40K, etc) in the μ scintillator.

External Gammas from decays in the acrylic, water, PMTs, etc. 11 n, p, C… n Cosmic Ray Muons α, Cosmogenics β Neutrons and radionuclides γ from spallation and hadronic showers

Fast Neutrons Alan Astbury Symposium, Universityfrom of external muons Victoria, April 2015 A.L. Hallin

Central Challenge: Backgrounds

Internal Radioactivity traces of radioisotopes (U/Th chain, 40K, etc) in the μ scintillator.

External Gammas from decays in the acrylic, water, PMTs, etc. 11 n, p, C… n Cosmic Ray Muons α, Cosmogenics β Neutrons and radionuclides γ from spallation and hadronic showers

Fast Neutrons Alan Astbury Symposium, Universityfrom of external muons Victoria, April 2015 A.L. Hallin

SNO+ Physics

Neutrinoless Double Beta Decay

Low Energy Solar Neutrinos

Reactor Antineutrinos

Geo-Neutrinos

Supernova Neutrinos

Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin e- Z ne bb Decay ne e- Requires Massive Majorana Neutrino Z+2 L=2 2 2 Two Neutrino Spectrum Zero Neutrino Spectrum 0 n  G0n M0 n mn 1% resolution (2 n) = 100 * (0 n) We learn M0n from nuclear physics e-

Z ne e- Z+2

0.0 0.5 1.0 1.5 2.0 Sum Energy for the Two Electrons (MeV) Endpoint Alan Astbury Symposium, EnergyUniversity of Victoria, April 2015 A.L. Hallin Neutrinoless Double Beta Decay in SNO+

n i

b 0nbb (200 meV) Loading tellurium metal into the nat V 18

e 0.3% Te loading k

2nbb

0 2

/ 16 8 y

SNO+ scintillator gives 800 kg of 5 yrs simulated B n ES

s t

130 n 14 2.22 MeV ( a, n) g u

Te at 0.3% loading o C 12 U Chain

10 Th Chain LAB scintillator with different Te loading levels External 8

4 0.3% 0.5 1% 3% 5% 2 0 % 2.2 2.3 2.4 2.5 2.6 2.7 2.8 Energy (MeV)

Expected 0νββ signal at roughly the current limit

Extremely low background compensates for modest energy resolution. If the TeLS is sufficiently radiopure, the dominant background in SNO+ will be 8B solar neutrinos. ThenAlan Astbury sensitivity Symposium, Universityscales of directly with Te loading! Victoria, April 2015 A.L. Hallin

Neutrinoless Double Beta Decay in SNO+

Excluded by EXO-200, GERDA, KamLAND-Zen

SNO+ Phase I - 0.5% Te

SNO+ Phase II - 3%Te

[eV]

ββ m

A staged approach will give SNO+ leading sensitivity for years Alan Astbury Symposium,to come. University of Victoria, April 2015 A.L. Hallin Background plot adapted from PRD 77, 113003 (2008) Solar Neutrinos

Precise measurements of the low energy solar neutrinos can confirm that we understand the neutrino oscillation mechanism, how neutrinos interact with matter, and what’s going on inside the sun.

SN O SNO: LETA

SNO +

Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin Solar Neutrinos

Precise measurements of the low energy solar neutrinos can confirm that we understand the neutrino oscillation mechanism, how neutrinos interact with matter, and what’s going on inside the sun.

LNGS SNOLAB

Alan Astbury Symposium, University of The depth of SNOLAB gives SNO+Victoria, a unique April opportunity2015 A.L. Hallin to make a precise measurement. Solar Physics: Neutrinos and Helioseismology are Probes of the Solar Interior

Accreted Metallicity and Mass:

Annual Review of Astronomy and Astrophysics 51:21-61 (Haxton, Robertson and Serenelli)

Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin Geo- and Reactor Antineutrinos

Detect antineutrinos via:

+ νe + p  e + n Delayed coincidence means very low backgrounds!

Measuring the geo-neutrino flux tells us about the earth’s internal chemical composition, and thermal history

Well known fluxes and baselines for reactor neutrinos provides precision probe of Alan Astbury Symposium,neutrino University oscillations of Victoria, April 2015 A.L. Hallin Supernova Neutrinos

• Type II supernovae release ~99% of their gravitational binding energy as neutrinos Expected signal for a 10kPc Supernova – More neutrinos in a few seconds than in the rest of the star’s life combined – Burst detectable at galactic distances • Galactic supernovae estimated to happen ~once in 30 years • Neutrinos provide “early warning” of supernova for optical observations • Neutrinos provide information on neutrino oscillations, the supernova itself, cosmological parameters, etc. Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin The SNO+ Story

• Past – Identify acrylic compatible scintillator – Install acrylic vessel hold-down net – Upgrade electronics – Clean acrylic vessel • Present – Design purification systems for tellurium and surfactant – Install scintillator purification plant – Fill detector with water – Upgrade calibrations and covergas systems • Future – Operate water filled detector to study backgrounds and nucleon decay - 2015 – Commission scintillator plant and fill detector with scintillator – 2015-2016 – Install isotope and surfactant purification equipment – 2016 – Purify and load DBDAlan isotope Astbury Symposium, – 2016 University-2017 of Victoria, April 2015 A.L. Hallin Install AV Hold-Down Net

Floor liner replacement

Hold-down anchors and new floor liner installed Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin Install AV Hold-Down Net

Hold-down rope net installed, pre-tensioned, and tested Alan Astbury Symposium, University of by “floatVictoria, the April 2015boat” A.L. Hallin testing. Scintillator Process System

Essentially had to install an industrial petrochemical processing facility underground. Major piping/vessel installation done, working on leak checking, then cleaning & passivation

Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin Scintillator Process System

Essentially had to install an industrial petrochemical processing facility underground. Major piping/vessel installation done, Alan Astbury Symposium, University of working on leak checking,Victoria, April then2015 A.L. Hallincleaning & passivation Acrylic Vessel Cleaning

Upper hemisphere – suspended platform Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin Acrylic Vessel Cleaning

View#from#New#Internal#CCD#Camera#System# Lower hemisphere - rotating ladder Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin Acrylic Vessel Cleaning

Even the outside! Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin Water Filling Camera and light Camera underwater, Camera above water underwater light above water

The detector and cavity are currently about half filled with water. This Alan Astbury Symposium, University of leadsVictoria, to interesting April 2015 A.L. Hallin optics! Conclusion

• SNO+ is a multipurpose neutrino detector capable of a number of important measurements – Priority on neutrinoless double beta decay – Also solar neutrinos, reactor and geo antineutrinos, and supernova neutrinos • Experiment is currently under construction, with water data expected this year. Then, on to scintillator fill and neutrinoless double beta decay!

Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin DEAP Collaboration

University of Alberta D. Grant, P. Gorel, A. Hallin, J. Soukup, C. Ng, B.Beltran, K. Olsen, R. Chouinard, T. McElroy, S. Crothers, S. Liu, P. Davis, and A. Viangreiro Carleton University K. Graham, C. Ouellet, Carl Brown Queen's University M. Boulay, B. Cai, D. B. Broerman, Bearse, J. Bonnat, K. Dering, M. Chen, S. Florian, R. Gagnon, V.V. Golovko, P. Harvey, M. Kuzniak, A. McDonald, C. Nantais, A.J. Noble, E. O’Dwyer, P. Pasuthip, L. Veloce, W. Rau, T. Sonley, P. Skensved, M. Ward SNOLAB/Laurentian B. Cleveland, F. Duncan, R. Ford, C.J. Jillings, T. Pollmann, C. Stone SNOLAB I. Lawson, K. McFarlane, P. Liimatainen, O. Li TRIUMF F. Retiere, Alex Muir, P-A. Amaudruz, D. Bishop, S. Chan, C. Lim, C. Ohlmann, K. Olchanski , V. Strickland National Autonomous University of Mexico E. Vazquez Jauregui Rutherford Appleton Laboratory P. Majewski Royal Holloway University of London J. Monroe, J. Walding, A. Butcher University of Sussex Simon Peeters Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin Solar n Measurements  Global Summary

Alan Astbury Symposium, University of Victoria, April 2015 A.L. Hallin