The XENON Dark Matter Project
Transcript of The XENON Dark Matter Project
The XENON Dark Matter ProjectLatest Results and Future Prospects
Constanze HasterokFor the XENON Collaboration
DPG Frühjahrstagung, Aachen 28.03.2019
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Indications for Dark Matter● Galactic Rotation Curves● Gravitational Lensing● Bullet Cluster● Cosmic Microwave
Background (CMB)● Structure Formation● Etc.
Bullet Cluster, Gravitational LensingNASA, Chandra x-ray observatory
CMB, arXiv: 1303.5062
arXiv: 0812.4005 [astro-ph]
Weakly Interacting MassiveParticles (WIMPs) are a favoured
model for dark matter!
Weakly Interacting MassiveParticles (WIMPs) are a favoured
model for dark matter!
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WIMP Detection Strategies
Direct Detection Ind
ir ect D
ete
ctio
nP
rod
ucti
on
at
Collid
ers
XENON, LUX, DEAP, CRESST, PICO, DAMA ...
Fermi, Ice Cube, AMS,...
ATLAS, CMS, ...
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The dual-phase TPC Technology● Light from prompt scintillation
(S1) and ionization (S2)● 3D position reconstruction● Background discrimination
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The XENON CollaborationLaborati Nazonali del
Gran Sasso (LNGS), Italy
~170 scientists from 27 institutions
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The XENON StoryXENON10 XENON100 XENON1T XENONnT
2005-2007Total: 25 kgTarget: 14 kgLimit: 8.8 x 10-44 cm-2
2008-2016Total: 162 kgTarget: 62 kgLimit: 1.1 x 10-45 cm-2
From 2019Total: ~8000 kgTarget: ~6000 kgSensitivity: 10-48 cm-2
2016-2018Total: 3200 kgTarget: 2000 kgLimit: 4.1 x 10-47 cm-2
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The XENON1T Infrastructure
Water Tank with Cherenkov Muon Veto
Cryostat with TPC
Cryogenic Systems + Purification System
Data Acquisition Systems
Distillation Column
&Gas Analytics
Xenon Recovery and Storage
Eur. P
hys
. J. C
77,
881 (
20
17)
Cryo-Pipe with cables
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XENON1T Science DataMore than one calendar year of stable data taking
SR0 – 34 live days SR1 – 247 live days
Eart
hq
uake + ~3 months
more data,→ being analyzed
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Background Composition Electronic Recoils Nuclear Recoils
Surface EventsAccidental Coincidences
Reference region:
(NR median, -2σ)
Major Backgrounds:● ER: 69% (in reference region)● NR: 26% (in reference region)
Detector-Artefacts: 5%(in reference region)
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Electronic Recoil BackgroundControlled by:● Screening of materials during detector
construction● 222Rn emanation measurements of materials● Cryogenic distillation of krypton● Fiducial volume selection
SourceFraction of ER
tot [%]
In 1.3T volume, (1-11)keV
222Rn 7585Kr 10
Solar Neutrinos 3
Materials 11136Xe 1
~80 evts/(t·y·keV)
Lowest ER background rate
ever achieved in a DM detector
XENON Preliminary
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Nuclear Recoil Background Controlled by:
● 3600 m.w.e rock overburden
● Water Cherenkov Muon Veto
● Screening of materials during detector construction
● Fiducial volume selection
● Single scatter requirement
● Total rate (NRtot): ~ 0.8 evts/(t·y)
SourceFraction of NR
tot [%]
In 1.3T volume, (5-41)keV
Radiogenic neutrons 96
CEνNSNS 4
Muon-induced neutrons < 1
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Event Distribution/Interpretation
● SR0 data re-analysis (32.13 d) + SR1 data (246.74 d): 279 live days● Results interpreted with unbinned profile likelihood analysis in (S1,S2,R)
space + segmentation of Z space into two bins arXiv:1902.11297
● Piecharts indicate the relative PDF from the best-fit of SI nucleon scattering of a 200 GeV/c2 WIMP with cross-section 4.4x10-47cm2
PR
L 12
1, 1
11
30
2 (2
01
8)
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● Most stringent limit for WIMPs > 6 GeV/c2
● Minimum: 4.1x10-47
cm² for a WIMP of 30 GeV/c2
● Factor 7 better sensitivity compared to other LXe TPCs
● Editor‘s Suggestion PRL 121, 111302 (2018)
Spin-Independent WIMP-nucleon scattering
XENON1T DM Search Results
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XENON1T DM Search Results
● 129Xe (spin-1/2): abundance of 26.4%● 131Xe (spin-3/2): abundance of 21.2%● Most stringent constraint on neutron-only interactions for WIMPs > 6 GeV/c2
● Minimum: 6.3 · 10-42 cm² @ 30 GeV/c2
Spin-Dependent WIMP-nucleon scattering
arX
iv: 19
02.0
3234
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XENON1T DM Search Results
● Model assumptions:– WIMP is Dirac fermion– Spin-1 mediator with axial-vector couplings– Isoscalar WIMP-nucleon interactions
Spin-Dependent WIMP-nucleon scattering:Comparison to Colliders in Simplified Model
arX
iv: 1902.0
32
34
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XENON1T DM Search Results
● XENON1T produced first experimental results!● Minimum of upper limit: 6.4 · 10-46cm2 @ 30 GeV/c2
Scalar WIMP-Pion coupling
PR
L 12
2, 0
71
30
1 (2
01
9)
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Upcoming XENON1T Results:Dark Matter Searches
Search for electron-DM interactions:● ALPs● Dark Photons● SuperWIMPs
Low mass WIMP searches(S2 only analysis)
Monoenergetic lines in the ER background
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Upcoming XENON1T Results:Nuclear Physics
Double Electron Capture of 124Xe
Neutrinoless double beta decay of 136Xe
XENON Preliminary
● QEC = 64.3 keV
● T1/2 > 2.1 · 1022 y (XMASS)
● Qββ = 2458 keV
● T1/2 > 1.07 · 1026 y
(KamLAND-Zen)
KamLAND-Zen
XENON Preliminary
XENON Preliminary
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XENONnT Strategy
Minimal Upgrade● Re-use XENON1T
infrastructure● Only exchange
TPC
Fiducial LXe Target● Total LXe: 8 tons● Fiducial mass: ~4
tons
Background● Reduce 222Rn
induced backgrounds by a factor of ~10
Fast Turnaround● XENONnT
commissioning in 2019
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New Features of XENONnTNew TPC
● PMT number increased by factor of 2
● Length: ~1.5 m Diameter: ~1.3 m
LXe-Purification● To achieve fast
cleaning of larger LXe volume (2500 SLPM)
● GXe purification (120 SLPM)
Neutron Veto● Gd in the Water
tank: 0.5% of Gd2(SO4)3
● 120 PMTs 8-inch PMTs (same as for Muon-Veto)
Radon-Distillation Column
● High throughput of 200 SLPM to extract Rn from TPC and remove from LXe
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Summary/OutlookXENONnT is on its way! Commissioning in 2019
Ongoing XENON1T Analyses:● Low mass WIMP searches with S2-only● DM-electron interactions: ALPs,
DarkPhotons, etc.● Double electron capture of 124Xe →
currently most sensitive experiment for this process
● Neutrinoless double beta decay of 136Xe
● Etc.
→ Stay Tuned!→ Stay Tuned!