Neutrino Physics with Future Dark Matter Detectors Jocelyn Monroe, Royal Holloway, University of London XVIII International Workshop on Neutrino Telescopes Venice, IT March 21, 2019 Dark Matter Direct Detection Signal:χN ➙χN χ χ Backgrounds: γ e- ➙ γ e- n N ➙ n N N ➙ N’ + α, e- ν N ➙ ν N experimental requirements: particle ID for recoil N, e-, alpha, n (multiple)γ final states γ Jocelyn Monroe March 21, 2019 / p. 2 Dark Matter Direct Neutrino Detection Signal: ν N ➙ ν N or ν e- ➙ ν e- ν ν Backgrounds: γ e- ➙ γ e- n N ➙ n N N ➙ N’ + α, e- χN ➙ χN? very similar requirements! ν (and ideally also measure direction) ν Jocelyn Monroe March 21, 2019 / p. 3 Neutrino Backgrounds to Dark Matter Searches and Directionality Jocelyn Monroe, MIT Jocelyn Monroe May 30, 2008 ν Cross Sections: ν-N Coherent Scattering Cross sections are coherently 2 2 -44 2 enhanced, ~ A x (Eν/MeV) x 10 cm recoils are O(10 KeV) D. Z. Freedman, Phys. Rev. D9. 1389 (1974) ν ν Z 2 Φ(solar B8 ν) = 2En Tmax = 5.86 x 106 cm-2 s-1 mnucleus + 2En N N Aprile et al., JCAP04 (2016) 027 O(tens) of events/ton-year = ~ 10-46 cm2 limit An irreducible background, without direction measurement! JM, P. Fisher, Phys. Rev. D 76:033007 (2007) Jocelyn Monroe May 30, 2008 What ν physics can future dark matter detectors do? https://masterclass.icecube.wisc.edu/en/learn/detecting-neutrinos Jocelyn Monroe March 21, 2019 / p. 6 Future Large-Mass Dark Matter Detectors Detector Technology: dual-phase Time Projection Chambers with 4-50 tonne liquid Xe, Ar targets read out primary scintillation: “S1” + proportional gas scintillation from drifted electrons: “S2” • x-y resolution ~cm • z resolution ~mm Goal: zeptobarn -> yoctobarn sensitivity to dark matter! https://lz.slac.stanford.edu/our-research/lz-research Jocelyn Monroe March 21, 2019 / p. 7 2-Phase TPCs: Near(ish) Future XENON-nT: 6 t LXe (active), following XENON-1T (LNGS), from 2019. PandaX-4: 4 t LXe (active), following PandaX (JinPing), from 2019. LZ: 7 t LXe (active), following LUX (SURF), from 2020. DarkSide-20k: 50 t LAr (LNGS), ArDM+DEAP+DS50+MiniCLEAN, from 2022. DARWIN: 50 t LXe (LNGS), following XENON-nT. ARGO: 500 t LAr (SNOLAB?), following DarkSide-20k. 5 cm x 5 cm tiled SiPM Jocelyn Monroe 8 Jan. 23, 2019 Backgrounds ? N Gamma ray interactions: electron recoil final states rate ~ Ne x (gamma flux), O(1E7) events/(kg day) mis-identified electrons mimic nuclear recoils Contamination: 238U and 232Th decays, recoiling progeny and mis-identified alphas, betas mimic nuclear recoils Neutrons: Nuclear recoil final state. (alpha,n), U, Th fission, cosmogenic spallation μ μ γ N* N n D. Malling, UCLA DM’16 + discrimination between e- vs. N Jocelyn Monroe March 21, 2019 / p. 9 Backgrounds ? N Gamma ray interactions: electron recoil final states rate ~ Ne x (gamma flux), O(1E7) events/(kg day) mis-identified electrons mimic nuclear recoils Contamination: 238U and 232Th decays, recoiling progeny and mis-identified alphas, betas mimic nuclear recoils Neutrons: Nuclear recoil final state. (alpha,n), U, Th fission, cosmogenic spallation μ μ γ N* N n D. Malling, UCLA DM’16 - Amaudruz, JM et al, Phys.Rev.Lett. 121 (2018) no.7, 071801 + discrimination between e vs. N Jocelyn Monroe March 21, 2019 / p. 10 Backgrounds ? N Gamma ray interactions: electron recoil final states rate ~ Ne x (gamma flux), O(1E7) events/(kg day) mis-identified electrons mimic nuclear recoils Contamination: 238U and 232Th decays, recoiling progeny and D.-M. Mei, A. Hime, PRD73:053004 (2006) mis-identified alphas, betas mimic nuclear recoils Neutrons: Nuclear recoil final state. (alpha,n), U, Th fission, cosmogenic spallation μ μ γ N* N n + discrimination between e- vs. N Jocelyn Monroe + large, active neutron shielding March 21, 2019 / p. 11 What ν physics can future dark matter detectors do? https://masterclass.icecube.wisc.edu/en/learn/detecting-neutrinos Jocelyn Monroe March 21, 2019 / p. 12 12 ) 10 -1 11 pp 10 7 What ν physics can bin Be -1 10 13 s 10 N -2 future dark matter detectors do? 109 15O 17 108 F 8B 107 Flux (cm hep ν 106 105 Solar 104 103 102 10-1 1 10 Neutrino Energy (MeV) https://masterclass.icecube.wisc.edu/en/learn/detecting-neutrinos Jocelyn Monroe March 21, 2019 / p. 13 Prospects for Solar ν-N Coherent Scattering −37 10 CRESST-III 2017 10−38 CDMSLite 2017 ] 2 10−39 10−40 [cm SI −41 DarkSide-50 2018 σ 10 ATLAS 2018 (Vector Z', 95% CL) 10−42 DEAP-3600 2017 −43 10 SuperCDMS Ge HV proj. LUX 2017 −44 10 PANDAX-II 2017 DarkSide-LM proj. DarkSide-50 2018 DEAP-3600 proj. −45 10 XENON1T 2018 LZ proj. −46 proj. 10 XENONnT proj. t yr yr proj. −47 DARWIN 200t 10 yr proj. r 3k t ecto det −48 ARGO 10 nne Dark Matter-Nucleon DarkSide-20k o200 00-t re 3 −49 Futu 10 Neutrino floor on xenon 10−50 −3 −2 −1 2 10 10 10 2 1 10 10 DarkSide-20k ESPP 2019 Mχ [TeV/c ] Jocelyn Monroe March 21, 2019 / p. 14 Solar ν-N Coherent Scattering (= Neutrino Bound) • sensitivity scales with sqrt(time) instead of linearly in time (with zero background) • background systematics become crucial PDFs in (energy, angle, time) of event for coherent solar neutrino background vs. background + dark matter signal are different! (includes angular resolution) Grothaus, Fairbairn, JM, Phys.ReV.D90 (2014) 055018 • annual modulation still contains information to differentiate dark matter vs. neutrinos • directionality gains 10x in sensitivity 6 GeV 30 GeV in the presence of backgrounds 1000 GeV solid = with direction no neutrino bound for directional detectors dotted = without direction • dashed = neutrino bound from simulation with Phys.Rev. D89, 023524 (2014) Jocelyn Monroe May 3, 2018 / p. 22 12 ) 10 -1 Solar ν-e Event Rates 11 pp 10 7 ν bin Be ν -1 10 13 s 10 N example event rates -2 109 15O of solar neutrino-electron Z, W 17 108 F elastic scattering at LNGS, 8B 107 per tonne-year of CF4 Flux (cm hep e e ν 106 105 Solar 104 103 102 10-1 1 10 Neutrino Energy (MeV) e.g. for Ar target: DarkSide-20k estimates 10k solar neutrino- electron elastic scatters above threshold per 100 tonne-yrs Aalseth, et al. Eur.Phys.J.Plus 133 (2018) Jocelyn Monroe March 21, 2019 / p. 15 Solar ν-Electron Scattering Via neutrino-electron elastic scattering, LAr dark matter experiments can observe the unmeasured CNO solar neutrino flux! (via spectral deformation) +with O(500 t-y), study the “solar metallicity problem”. Franco et al., JCAP 1608 (2016) 08 Cerdeno, Davis, Fairbairn, Vincent, JCAP 1804 (2018) 37 big opportunity: distinguish exclusion betweendetection high vs. low metallicity. big challenges: Rn background suppression and uncertainty on cosmogenics *Xe-136 background makes LXe CNO challenging Baudis et al., JCAP 1401 (2014) 044, Jocelyn Monroe March 21, 2019 / p. 16 (P. Agnes, JM in preparation) What about Electron Directionality? potential increase in sensitivity / reduction in exposure to discovery from electron recoil direction • 1 mm sampling pitch in drift direction makes direction reconstruction of ~cm length electron tracks feasible in 1D • directional dark matter detection studies show 1D direction reconstruction gains 10x over non-directional measurements in the presence of backgrounds Mayet, JM et al., Phys.Rept. 627 (2016) 0.45 zenith θ 0.4 1.75 MeV ) / zenith 0.35 1.5 MeV θ 0.3 1.0 MeV (cos σ 0.25 0.2 0.15 0.1 exclusion detection 0.05 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 θzenith (radians) Jocelyn Monroe March 21, 2019 / p. 17 What neutrino physics can (if lucky!) future dark matter detectors do? for a supernova at 10 kPc, expect 300-500 ν-N events in DarkSide-20k, XENON-nT, LZ, up to few k in DARWIN. Lang et al., Phys. Rev. D 94 (2016) • measure all flavors via NC 40 - 40 • measure νe Ar e K* • multi-messenger observation: sub-eV mass ordering? Arnaud et al., Phys.Rev.D.65.033010 https://masterclass.icecube.wisc.edu/en/learn/detecting-neutrinos Jocelyn Monroe May 3, 2018 / p. 7 ) -1 105 s 238 What neutrino physics can -2 U 104 235U future dark matter detectors do? 3 10 232Th Flux (cm 40 ν 102 K Geo 10 1 10-1 10-2 0.5 1 1.5 2 2.5 3 3.5 4 4.5 Anti-Neutrino Energy (MeV) https://masterclass.icecube.wisc.edu/en/learn/detecting-neutrinos Jocelyn Monroe March 21, 2019 / p. 18 in a 10n T-year exposure… Contribution from geo-neutrinos is non- to ν-e scattering rate: ~few% low E dominated by the (not-yet- study with 500 neutrino background events measured) K-40 (Q = 1.3 MeV). Leyton, Dye, JM, Nature Commun. 8 (2017) 15989 Example: ν-e elastic scatters per kt-yr at LNGS, on CF4 ν-N scattering: Gelmini et al, arXiv:1812.05550 Jocelyn Monroe March 21, 2019 / p. 2 Geo ν-Electron Scattering PLR analysis of energy, time, and direction shows sensitivity at 95% CL to measure K-40 geo-neutrino flux with O(100) t-yr exposure. study with 500 neutrino background events example: geo-, solar-, reactor-ν -induced electron recoil directions, at LNGS. challenge: measure the direction of ~1 MeV e- recoils…. Leyton, Dye, JM, Nature Commun. 8 (2017) 15989 Jocelyn Monroe March 21, 2019 / p. 20 What neutrino physics can future dark matter detectors do? diffuse supernovae back- ground: perhaps within reach in large exposures if could reject neutrino scatters! (requires directional nuclear recoil detection) Albers et al., JCAP 1611 (2016) Aprile et al., JCAP04 (2016) 027 https://masterclass.icecube.wisc.edu/en/learn/detecting-neutrinos Jocelyn Monroe May 3, 2018 / p.