Introduction to THEIA and low-energy neutrino program 70m 18m - PowerPoint PPT Presentation

Introduction to THEIA and low-energy neutrino program 70m 18m MooD Workshop T HEIA25 BNL, Nov 12, 2019 20m Michael Wurm (JGU Mainz) for the THEIA proto-collaboration

What is THEIA? → Enhanced sensitivity to broad physics program scintillation Novel target medium: Water-based Liquid Scintillator Long-Baseline Oscillations Cherenkov Solar neutrinos Supernova neutrinos Novel light sensors: Diffuse SN neutrinos LAPPDs, dichroicons Large volume detector Neutrinoless able to exploit both Double-Beta Decay Cherenkov+Scintillation signals Novel reconstruction techniques THEIA 2

THEIA Technology → how to generate (and preserve!) scintillation and Cherenkov photons? scintillation Attenuation length (m) 125 Cherenkov Water (SK,SNO) 100 WbLS mycels 75 Water-based Liquid Scintillator Water-like Oil-like 50 § >70% water § loading of § Cherenkov+ hydrophilic o scintillation elements t t n e r a p s § cost-effective n a ! r s t n y o t l t o n e h 25 i p c i v f f o u k S n Scintillator e r e h C t c a r Borexino t x e KamLAND 0 10 2 10 3 10 4 Photon yield (MeV) → target medium can be adjusted to physics goals! Michael Wurm (Mainz) THEIA 3

THEIA Technology → how to generate (and preserve!) scintillation and Cherenkov photons? scintillation Cherenkov → how to separate the Cherenkov/scintillation signals? Timing Spectrum Angular distribution “instantaneous chertons” UV/blue scintillation vs. increased PMT hit density vs. delayed “scintons” blue/green Cherenkov under Cherenkov angle → ns resolution or better → wavelength-sensitivity → sufficient granularity Michael Wurm (Mainz) THEIA 4

THEIA Technology → how to generate (and preserve!) scintillation and Cherenkov photons? scintillation Cherenkov → how to separate the Cherenkov/scintillation signals? Timing Spectrum Angular distribution “instantaneous chertons” UV/blue scintillation vs. increased PMT hit density vs. delayed “scintons” blue/green Cherenkov under Cherenkov angle → ns resolution or better → wavelength-sensitivity → sufficient granularity Dichroic filters LAPPDs: ~ 60ps timing Standard PMTs → talk by Tanner Kaptanoglu Michael Wurm (Mainz) THEIA 5

THEIA Technology → how to generate (and preserve!) scintillation and Cherenkov photons? scintillation Cherenkov → how to separate the Cherenkov/scintillation signals? Large Area Picosecond Photon Detectors Timing § Area: 20-by-20 cm 2 “instantaneous chertons” vs. delayed “scintons” § Amplification of p.e. by two MCP layers → ns resolution or better § Flat geometry: ultrafast timing ~65ps § Strip readout: spatial resolution ~1cm § Commercial production by Incom, Ltd. LAPPDs: ~ 60ps timing Michael Wurm (Mainz) THEIA 6

THEIA R&D and friends ANNIE @ Fermilab BNB Selected examples of on-going R&D: → demonstrator for LAPPDs CHESS setup at UC Berkeley: → WbLS upgrade foreseen Image Cherenkov rings from WbLS + C/S timing timing in rings → Dichroicons at U.Penn Simultaneous but discriminating detection of chertons & scintons → talk by T. Kaptanoglu WATCHMAN-AIT Toplogical reconstruction at U.Hamburg → test of Using (Wb)LS volume as THEIA-related “photon TPC“ by tracking technologies back photons for enhanced emission probability → talk by Adam Bernstein ß 0.5GeV µ in WbLS+LAPPDs THEIA 7

THEIA25 as the Module of Opportunity 70m Detector specifications 18m § Total mass: 25 kt of WbLS T HEIA25 § Fiducial mass: 17-20 kt (depends on physics) 20m § Photosensors in Phase 1 (LBL): 22,500x 10’’ PMTs → 25% coverage w/ high QE 700x 8’’ LAPPDs → 3% coverage → equals the current photon collection of SK! § Background levels: Radiopurity (H 2 O): ~10 -15 g/g in 238 U, 232 Th, 40 K Rock shielding: 4300 m.w.e. → muon flux only ~10% of LNGS Michael Wurm (Mainz) THEIA 8

THEIA25 : Staged Approach 70m 18m T HEIA25 Physics Goals 20m § Long-Baseline Oscillations Staged Approach § Proton decay → K + ν/π 0 e + Phase 1 Long-baseline neutrinos (LBNF) § Supernova neutrinos with ”thin” WbLS (1-10%) § Diffuse SN neutrinos Phase 2 Low-energy neutrino § Solar neutrinos observation with “oily” LS § Geoneutrinos Phase 3 multi-ton scale 0 νββ search with loaded LS in suspended vessel νββ search § 0 νβ and added photocoverage on <10meV scale Michael Wurm (Mainz) THEIA 9

WbLS: Impact on MeV neutrino detection Michael Wurm (Mainz) THEIA 10

Supernova Neutrinos Galactic Supernovae (10kpc): Expected events: ~5,000, mostly ) 𝝃 𝒇 ‘s from IBD § complementary to 𝜉 - signal in argon § Same location: compare Earth matter effects § Provide fast trigger for Lar TPCs, especially for far-off Supernovae (LMC: ~200 ev. In THEIA) Reconstructing Entries Entries 600 600 c c 2 2 / ndf / ndf eES 200 380.6 / 1795 380.6 / 1795 ES electron ± ± norm norm 110 110 10.24 10.24 q q ° ° ± ± ( ( ) ) 0.5753 0.5753 1.239 1.239 Detection channels can be separated due to IBD 4000 f f ° ° ± ± direction ( ( ) ) 0.8371 0.8371 1.193 1.193 s s ° ° ± ± ( ( ) ) 10.6 10.6 0.8488 0.8488 tag eff. 90% ± ± const. const. 0.3462 0.3462 0.02005 0.02005 neutron & delayed decay tags θ 0 0.57 ± 1.24 ϕ 0 0.84 ± 1.19 § some all-flavor ( ν e + ν µ + ν τ ) information 9 8 from NC reactions on oxygen 7 6 5 § Enhanced SN pointing: ∼ 2° based on ES 4 3 with IBD background subtraction 2 150 1 ° ) ( 100 f 0 D 50 80 D q 60 0 ° ( 40 ) - 20 50 0 - - 20 100 - 40 - - 60 150 - 80 Michael Wurm (Mainz) THEIA 11

Diffuse Supernova Neutrino Background DSNB detection: Cherenkov/scintillation ratio for BG discrimination § Low-flux 𝒫 (10 2 cm -2 s -1 ) ̅ 𝜉 - signal → detectable by IBD: ~2 ev. per 10 kt ∙ yrs § Requires efficient BG discrimination, especially to atmospheric ν NC interactions § In THEIA: NC BG data by ANNIE! o ring counting: o Cherenkov/scintillation ratio o delayed decay tags Signal/BG spectra and observation window → signal efficiency: 95% → residual background: 1.7% very clean measurement cf. JUNO & SK-Gd THEIA25: 5 IBDs over 2.7 BG per year → 5 σ discovery after 6 years Michael Wurm (Mainz) THEIA 12

Solar neutrinos Objectives: § Precise measurement of CNO neutrino flux stellar physics, solar metallicity § Spectral upturn of low-energy 8 B neutrinos matter effects, BSM physics? → require efficient BG discrimination and sufficient light yield in 1-3 MeV range § THEIA25: 2D directional & spectral fit → CNO flux at 10% level after 5 yrs R. Bonventre, G.D. Orebi Gann, Eur. Phys. J. C (2018) 78:435 Spectral fit (cf. Borexino) Directional fit (cf. Super-Kamiokande) Michael Wurm (Mainz) THEIA 13

Neutrinoless double-beta decay Insertion of subvolume holding 1.8kt of organic scintillator (LAB+PPO) Sensitivity (90% CL) from spectral fit: loading: -- 3% enriched Xe (89.5%) § Te: T 1/2 > 1.1x10 28 yrs, m ββ < 6.3 meV -- 5% natural Te (~90t) § Xe: T 1/2 > 2.0x10 28 yrs, m ββ < 5.6 meV enhanced 1200 pe/MeV (cf. JUNO) [eV] photo-cov. → 3% energy resolution - b 1 10 b discovery sensitivity on m Energy spectrum (ROI) - 2 10 s 3 LEGEND-1000 CUPID CUPID-reach SNO+II PandaX-III-1000 KamLAND2-Zen nEXO CUPID-1T Theia-Te NEXT-BOLD Theia-Xe NEXT-HD Plot by Yu. G. Kolomensky using methodology from Agostini, Benato, Detwiler: PhysRevD.96.053001 Michael Wurm (Mainz) THEIA 14

THEIA Whitepaper online! arXiv:1911.03501 THEIA proto-collaboration: groups from 35+ institutions and eight countries (CA, CN, DE, FI, IT, KR, UK, US) Read more on: § Detector technology § Low energy neutrinos, e.g. geoneutrinos § Nucleon decay § LBL oscillations Mike Wilking’s talk 15

Backup Slides 70m 18m T HEIA25 20m 16

Supernova neutrino pointing Toy-MC study § Realistic kinematics for ES § Flat for IBD (conservative) § “canonical“ SN model (used for JUNO) § eES events: 200 in 20kt § IBD events: 4000 § IBD tagging efficiency: 0% → 90% → 100% § Angular resolution (at 10MeV+) 10° → 15° → 20° § Results of a 2D analytical fit: IBD tag Angular resolution efficiency 10° 15° 20° 0% 1.55 1.55 2.05 90% 1.75 1.95 2.55 100% 2.95 5.45 11.35

DSNB – spectrum before cuts visible scintillation energy (MeV) 0 5 10 15 20 25 30 35 40 45 100 p.e.) DSNB 3 Reactor BG 10 AtmCC BG AtmNC BG 2 10 Li9 BG ´ events /(100 ktyr FastN BG 10 1 - 1 10 - 2 10 ´ 3 10 - 3 10 0 1 2 3 4 5 6 scintillation p.e.

DSNB Ring Counting AtmNC events visible scintillation energy (MeV) 0 5 10 15 20 25 30 35 350 One-Ring 300 Multi-Ring No-Ring 250 200 150 100 50 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 scintillation p.e.

DSNB C/S ratio background rejection Background Reduction [%] 1 2 3 4 5 6 7 8 9 yr) S+B 26 3.6 ´ DSNB Rate /(100 kt 24 3.5 S/ 22 3.4 3.3 20 3.2 18 3.1 16 3.0 14 2.9 12 2.8 82% signal efficiency 10 5 5 10 10 15 15 20 20 25 25 30 30 35 35 ´ AtmNC Rate /(100 kt yr)

DSNB Delayed decay tags ß taggable ß taggable

DSNB Signal and Background Rates