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Searching for low-mass dark matter particles with a massive Ge - - PowerPoint PPT Presentation

Dec 15, 2023 393 likes •910 views

Slides at: bradkav.net/talks.html 1 Searching for low-mass dark matter particles with a massive Ge bolometer operated above-ground arXiv:1901.03588, Phys. Rev. D 99, 082003 (2019) Bradley J. Kavanagh GRAPPA, University of Amsterdam working

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SLIDE 1

Searching for low-mass dark matter particles with a massive Ge bolometer operated above-ground

arXiv:1901.03588, Phys. Rev. D 99, 082003 (2019)

LHC Results Forum - 3rd June 2019

@BradleyKavanagh b.j.kavanagh@uva.nl

Bradley J. Kavanagh GRAPPA, University of Amsterdam working with the EDELWEISS Collaboration

Slides at: bradkav.net/talks.html

1

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SLIDE 2

Looking for tiny and tough WIMPs with EDELWEISS-surf

arXiv:1901.03588, Phys. Rev. D 99, 082003 (2019) @BradleyKavanagh b.j.kavanagh@uva.nl Slides at: bradkav.net/talks.html

LHC Results Forum - 3rd June 2019 Bradley J. Kavanagh GRAPPA, University of Amsterdam working with the EDELWEISS Collaboration

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Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

EDELWEISS (EDW) Collaboration

[April 2016] + Me…

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Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Searching for Dark Matter

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Charge (ionisation) Heat (phonons) Light (scintillation) Detector

Target nucleus

mχ 1 GeV vχ ∼ 10−3 c

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χ

<latexit sha1_base64="2nJGzoVtZOM+N/8kUwoO4SuzA=">AB63icbVBNS8NAEJ3Ur1q/qh69LBbBU0lqQY9FLx4r2A9oQ9lsN83S3U3Y3Qgl9C948aCIV/+QN/+NmzYHbX0w8Hhvhpl5QcKZNq7ZQ2Nre2d8q7lb39g8Oj6vFJV8epIrRDYh6rfoA15UzSjmG036iKBYBp71gepf7vSeqNIvlo5kl1Bd4IlnICDa5NCQRG1Vrbt1dAK0TryA1KNAeVb+G45ikgkpDONZ64LmJ8TOsDCOczivDVNMEkyme0IGlEguq/Wx6xdWGWMwljZkgYt1N8TGRZaz0RgOwU2kV71cvE/b5Ca8MbPmExSQyVZLgpTjkyM8sfRmClKDJ9Zgoli9lZEIqwMTaeig3BW315nXQbde+q3nho1lq3RxlOINzuAQPrqEF9CGDhCI4Ble4c0Rzovz7nwsW0tOMXMKf+B8/gABCI42</latexit>

Galactic ‘wind’ of DM particles

  • Low energy nuclear recoils —> need low energy threshold O(keV)
  • Rare event search —> need large target mass
  • Large backgrounds —> need shielding and underground labs

Look for Dark Matter in the form of new Weakly Interacting Massive Particles (WIMPs)

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Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

  • [/]
  • σ []
  • σ []
  • -
  • Direct Detection Landscape

5

  • [/]
  • σ []
  • σ []
  • Spin-independent DM-nucleon interactions

Spin-dependent DM-neutron interactions EDELWEISS-III

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SLIDE 6

Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

  • [/]
  • σ []
  • σ []
  • -
  • Direct Detection Landscape

6

  • [/]
  • σ []
  • σ []
  • Spin-independent DM-nucleon interactions

Spin-dependent DM-neutron interactions EDELWEISS-III “Leave no stone unturned!” [Bertone & Tait - 1810.01668]

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Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

EDELWEISS-III

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~20 kg Cryogenic Germanium mass (24 x ~800g FID800 modules) Operated in underground lab in Modane, France (1700 m rock —> 5 μ/m2/day) (continuous operation since Summer 2014) [EDW: 1603.05120, 1607.03367, 1706.01070] 50 cm Polyethylene + 20cm Lead shielding Measure heat and ionisation to discriminate electron and nuclear recoils Energy threshold of 2.5 keV —> sensitivity down to WIMP masses of 4 GeV 496 kg-day exposure reported so far

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Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

EDELWEISS-surf

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Technological development for DM searches and coherent neutrino-nucleus scattering [EDW: 1703.08957,1803.03463] RED20: Single 33.4g Ge detector with neutron- transmutation-doped Ge (Ge-NTD) phonon sensor Data taking in a surface lab in Lyon (IPNL) for 6 days with minimal shielding Direct measurement of total deposited energy - no quenching, but also no event discrimination Small ~0.03 kg-day exposure

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Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Why I love EDELWEISS-surf

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Very low energy threshold: 60 eV Minimal shielding Tiny WIMPs Tough WIMPs

10−2 10−1 100 Recoil energy, ER [keV] 106 107 108 109 1010 1011 dR/dER [events/keV/kg/day] Ge, σSI = 10−30 cm2 mχ = 0.5 GeV mχ = 1 GeV mχ = 2 GeV

Detector Shielding Earth Atmosphere

χ

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Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Overview

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EDELWEISS-surf Earth-shielding effects Sub-sub-GeV Dark Matter searches The future

Energy [keV] 1 2 3 4 5 6 7 8 Event rate [evts/kg/keV/day)]

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0.05 0.1 0.15 0.2

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Data Noise induced triggers Residual

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Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

RED20

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Single 33.4g Ge detector (20mm x 20mm) with neutron- transmutation-doped Ge (Ge-NTD) phonon sensor [Credit: Julien Billard] 200 eV pulse

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Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Energy [keV]

1 −

10 1 Efficiency 0.1 0.2 0.3 0.4

Trigger and Livetime cuts

2

χ ∆ + cut

normal 2

χ + Analysis threshold

Calibration and Resolution

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60 eV energy threshold Calibrated with low energy X-rays from 55Fe 18 eV RMS energy resolution No ionisation read-out (only phonons) - total deposited energy is collected, allowing for a low threshold

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Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Energy [keV] 1 2 3 4 5 6 7 8 Event rate [evts/kg/keV/day)]

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0.05 0.1 0.15 0.2

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Data Noise induced triggers Residual

Data

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Energy spectrum recorded in the blinded day (26th May 2018)

  • f the DM search data, after all cuts.

What would a Dark Matter signal look like?

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Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

10−2 10−1 100 Recoil energy, ER [keV] 106 107 108 109 1010 1011 dR/dER [events/keV/kg/day] Ge, σSI = 10−30 cm2 mχ = 0.5 GeV mχ = 1 GeV mχ = 2 GeV

Dark Matter scattering rate

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χ

Detector DM flux:

Focus on DM-nucleus scattering

Convolve with DM-nucleus cross section to obtain nuclear recoil rate: Spin-independent (SI):

σA

SI ∝ σp SIA2

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Spin-dependent (SD):

dR dER ∝ ρχ mχ ∞

vmin

vf(v) dσ dER dv

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Φχ = ρχ mχ vf(v)

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σA

SD σp,n SD Sp,n2

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(Spin-content dominated by single unpaired neutron in 73Ge)

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Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Detector Response

15

10−2 10−1 100 Input Energy [keV] 10−2 10−1 100 Output Energy [keV]

Pulse Simulations (including cuts)

10−2 10−1 100 Input Energy [keV]

Analytic Response (including cuts)

10−3 10−2 10−1 100 101 P(Eout|Ein) [keV−1]

Convolve recoil spectrum with detector response to obtain expected distribution of events Simulate 107 simulated DM signal pulses and determine reconstructed energy

  • also developed more efficient analytic model for the detector response:
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Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Signal and Data

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10−1 100 Energy [keV] 102 103 104 105 Number of counts [evts/keV] Standard Spectra

Background Model Analysis Threshold (60 eV) Data Excluded WIMP model: 0.7 GeV/c2, 9.8 × 10−35 cm2 Excluded WIMP model: 2.0 GeV/c2, 4.5 × 10−37 cm2 Excluded WIMP model: 10.0 GeV/c2, 1.1 × 10−37 cm2

Set upper limit based on optimal poisson interval (given empirical background model from 5 days unblinded data) ‘Unsmeared’ spectra

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Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

]

2

WIMP Mass [GeV/c

2 −

10

2 −

10 × 2

1 −

10

1 −

10 × 2 1 2 3 4 5 6 7 10 ]

2

WIMP-nucleon cross section [cm

45 −

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EDELWEISS-Surf (Standard) EDELWEISS-III LT CRESST Surface CRESST-II SuperCDMS LT CDMSLite LUX (Standard) LUX (Migdal) XENON1T (Standard) XENON100 LT NEWS-G DarkSide (Standard) XQC CMB Neutrino discovery limit

EDELWEISS-surf Limits: Spin-independent

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EDELWEISS-surf Strongest above-ground limit, down to 600 MeV First sub-GeV limit with Ge, down to 500 MeV

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Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

EDELWEISS-surf Limits: Spin-dependent

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[See also recent results from CRESST-III, 1904.00498]

1 −

10 × 2 1 2 3 4 5 6 7 10 20 30 )

2

WIMP Mass (GeV/c

41 −

10

39 −

10

37 −

10

35 −

10

33 −

10

31 −

10

29 −

10

27 −

10

25 −

10

23 −

10 )

2

SD WIMP-Neutron Cross Section (cm

EDELWEISS-Surf EDELWEISS-Surf Migdal RRS-Balloon XQC CDMSLite LUX PandaX-II XENON1T

1 −

10 1 2 3 4 5 6 7 10 20 30 )

2

WIMP Mass (GeV/c

EDELWEISS-Surf RRS-Balloon XQC CDMSLite LUX PandaX-II XENON1T

EDELWEISS-surf WIMP-neutron

1 −

10 × 2 1 2 3 4 5 6 7 10 20 30 )

2

WIMP Mass (GeV/c

41 −

10

39 −

10

37 −

10

35 −

10

33 −

10

31 −

10

29 −

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27 −

10

25 −

10

23 −

10 )

2

SD WIMP-Proton Cross Section (cm

EDELWEISS-Surf RRS-Balloon CMB CDMSLite LUX PandaX-II XENON1T PICO-60-II

1 −

10 1 2 3 4 5 6 7 10 20 30 )

2

WIMP Mass (GeV/c

EDELWEISS-Surf RRS-Balloon CMB CDMSLite LUX PandaX-II XENON1T PICO-60-II

EDELWEISS-surf WIMP-proton World-leading limits on SD-neutron interactions below 1.5 GeV!

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Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Tough WIMPs

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  • r “Earth-scattering effects in (sub)-surface direct detection experiments”
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Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Journey to the centre of the Earth

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Detector Shielding Earth Atmosphere

χ

Strongly Interacting Massive Particles (SIMPs) may scatter before reaching the detector! Collar & Avignone - PLB 275, 1992 and others Kouvaris & Shoemaker - 1405.1729,1509.08720, DAMA - 1505.05336, BJK, Catena, Kouvaris - 1611.05453, Emken & Kouvaris - 1706.02249, 1802.04764, Mahdawi & Farrar - 1709.00430, 1804.03073, Davis - 1708.01484, BJK - 1712.04901, Hooper & McDermott - 1802.03025, and many others…

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Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Earth-scattering Effects

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Moderate DM interactions before reaching the detector may lead to strong anisotropy (and daily modulation) due to Earth’s motion and rotation: But for very large cross sections, the biggest effect is attenuation… [BJK, Catena, Kouvaris - 1611.05453]

Semi-analytic calculation for O(1) scatter before reaching the detector

Detector

χ

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Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Surface Sub-surface

Attenuation

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[BJK, 1712.04901]

d Eχ dx =

  • i

ni(r) ERi σi(v)

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Follow ‘straight-line’ trajectories of DM particles as they scatter and continuously lose energy: At large enough cross sections, particles drop below threshold…

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Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Setting SIMP limits

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Use semi-analytic code verne (https://github.com/bradkav/verne) to calculate speed distribution

  • f SIMP DM at the detector, including scattering in the atmosphere, Earth, buildings and shielding



 Incorporate full 3-D incoming DM velocity distribution, but assume straight-line trajectories Stop tracking DM particles below v = 20 km/s - here the calculations are no longer reliable [Credit: Maryvonne De Jesus ] [1802.04764]

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Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Comparison with detailed Monte Carlo

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[Emken & Kouvaris - 1706.02249, 1802.04764] Comparison with careful, 3D Monte Carlo (including particle deflections) yields similar results: DaMaSCUS: https://github.com/temken/DaMaSCUS
 DaMaSCUS-CRUST: https://github.com/temken/damascus-crust We use this semi-analytic ‘straight-line’ trajectory approach, because its computationally cheap.


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Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Comparison with detailed Monte Carlo

25

Excluded region from CRESST-surface (2017) using different calculations [Emken & Kouvaris - 1706.02249, 1802.04764] M

  • n

t e C a r l

  • O

u r a p p r

  • a

c h We use this semi-analytic ‘straight-line’ trajectory approach, because its computationally cheap.
 Comparison with careful, 3D Monte Carlo (including particle deflections) yields similar results: DaMaSCUS: https://github.com/temken/DaMaSCUS
 DaMaSCUS-CRUST: https://github.com/temken/damascus-crust

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Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

]

2

WIMP Mass [GeV/c

2 −

10

2 −

10 × 2

1 −

10

1 −

10 × 2 1 2 3 4 5 6 7 10 ]

2

WIMP-nucleon cross section [cm

45 −

10

44 −

10

43 −

10

42 −

10

41 −

10

40 −

10

39 −

10

38 −

10

37 −

10

36 −

10

35 −

10

34 −

10

33 −

10

32 −

10

31 −

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30 −

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29 −

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26 −

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25 −

10

24 −

10

EDELWEISS-Surf (Standard) EDELWEISS-III LT CRESST Surface CRESST-II SuperCDMS LT CDMSLite LUX (Standard) LUX (Migdal) XENON1T (Standard) XENON100 LT NEWS-G DarkSide (Standard) XQC CMB Neutrino discovery limit

EDELWEISS-surf Limits: Spin-independent

26

EDELWEISS-surf

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Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

]

2

WIMP Mass [GeV/c

2 −

10

2 −

10 × 2

1 −

10

1 −

10 × 2 1 2 3 4 5 6 7 10 ]

2

WIMP-nucleon cross section [cm

45 −

10

44 −

10

43 −

10

42 −

10

41 −

10

40 −

10

39 −

10

38 −

10

37 −

10

36 −

10

35 −

10

34 −

10

33 −

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32 −

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31 −

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30 −

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10

25 −

10

24 −

10

EDELWEISS-Surf (Standard) EDELWEISS-III LT CRESST Surface CRESST-II SuperCDMS LT CDMSLite LUX (Standard) LUX (Migdal) XENON1T (Standard) XENON100 LT NEWS-G DarkSide (Standard) XQC CMB Neutrino discovery limit

EDELWEISS-surf Limits: Spin-independent

27

EDELWEISS-surf One of the first ‘official’ SIMP limits from a direct detection experiment - exclude up to 10-27 cm2

slide-28
SLIDE 28

Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

]

2

WIMP Mass [GeV/c

2 −

10

2 −

10 × 2

1 −

10

1 −

10 × 2 1 2 3 4 5 6 7 10 ]

2

WIMP-nucleon cross section [cm

45 −

10

44 −

10

43 −

10

42 −

10

41 −

10

40 −

10

39 −

10

38 −

10

37 −

10

36 −

10

35 −

10

34 −

10

33 −

10

32 −

10

31 −

10

30 −

10

29 −

10

28 −

10

27 −

10

26 −

10

25 −

10

24 −

10

EDELWEISS-Surf (Standard) EDELWEISS-III LT CRESST Surface CRESST-II SuperCDMS LT CDMSLite LUX (Standard) LUX (Migdal) XENON1T (Standard) XENON100 LT NEWS-G DarkSide (Standard) XQC CMB Neutrino discovery limit

EDELWEISS-surf Limits: Spin-independent

28

EDELWEISS-surf One of the first ‘official’ SIMP limits from a direct detection experiment - exclude up to 10-27 cm2 CMB XQC -Rocket

slide-29
SLIDE 29

Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

1 −

10 × 2 1 2 3 4 5 6 7 10 20 30 )

2

WIMP Mass (GeV/c

41 −

10

39 −

10

37 −

10

35 −

10

33 −

10

31 −

10

29 −

10

27 −

10

25 −

10

23 −

10 )

2

SD WIMP-Proton Cross Section (cm

EDELWEISS-Surf RRS-Balloon CMB CDMSLite LUX PandaX-II XENON1T PICO-60-II

1 −

10 1 2 3 4 5 6 7 10 20 30 )

2

WIMP Mass (GeV/c

EDELWEISS-Surf RRS-Balloon CMB CDMSLite LUX PandaX-II XENON1T PICO-60-II

1 −

10 × 2 1 2 3 4 5 6 7 10 20 30 )

2

WIMP Mass (GeV/c

41 −

10

39 −

10

37 −

10

35 −

10

33 −

10

31 −

10

29 −

10

27 −

10

25 −

10

23 −

10 )

2

SD WIMP-Neutron Cross Section (cm

EDELWEISS-Surf EDELWEISS-Surf Migdal RRS-Balloon XQC CDMSLite LUX PandaX-II XENON1T

1 −

10 1 2 3 4 5 6 7 10 20 30 )

2

WIMP Mass (GeV/c

EDELWEISS-Surf RRS-Balloon XQC CDMSLite LUX PandaX-II XENON1T

EDELWEISS-surf Limits: Spin-dependent

29

WIMP-neutron WIMP-proton EDELWEISS-surf EDELWEISS-surf

slide-30
SLIDE 30

Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

1 −

10 × 2 1 2 3 4 5 6 7 10 20 30 )

2

WIMP Mass (GeV/c

41 −

10

39 −

10

37 −

10

35 −

10

33 −

10

31 −

10

29 −

10

27 −

10

25 −

10

23 −

10 )

2

SD WIMP-Proton Cross Section (cm

EDELWEISS-Surf RRS-Balloon CMB CDMSLite LUX PandaX-II XENON1T PICO-60-II

1 −

10 1 2 3 4 5 6 7 10 20 30 )

2

WIMP Mass (GeV/c

EDELWEISS-Surf RRS-Balloon CMB CDMSLite LUX PandaX-II XENON1T PICO-60-II

1 −

10 × 2 1 2 3 4 5 6 7 10 20 30 )

2

WIMP Mass (GeV/c

41 −

10

39 −

10

37 −

10

35 −

10

33 −

10

31 −

10

29 −

10

27 −

10

25 −

10

23 −

10 )

2

SD WIMP-Neutron Cross Section (cm

EDELWEISS-Surf EDELWEISS-Surf Migdal RRS-Balloon XQC CDMSLite LUX PandaX-II XENON1T

1 −

10 1 2 3 4 5 6 7 10 20 30 )

2

WIMP Mass (GeV/c

EDELWEISS-Surf RRS-Balloon XQC CDMSLite LUX PandaX-II XENON1T

EDELWEISS-surf Limits: Spin-dependent

30

EDELWEISS-surf Earth-scattering effects relevant at low mass! EDELWEISS-surf WIMP-neutron WIMP-proton Most SD stopping comes from Nitrogen in the atmosphere

slide-31
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Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Tiny, tiny WIMPs

31

  • r “Searching for very sub-GeV Dark Matter with low-threshold detectors”
slide-32
SLIDE 32

Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Kinematic Limit for Elastic Scattering

32

[Credit: Julien Billard] Intrinsic thermodynamic limit for ~10g detectors Maximum DM speed set by galactic escape speed (~544 km/s) plus Solar orbital speed (~220 km/s)

slide-33
SLIDE 33

Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Migdal Effect

33

[1711.09906] Could also look for the emission of a photon along with the nuclear recoil, but this turns out to be subdominant Consider instead inelastic scattering. In particular, look for the possible ionisation

  • f an electron after a DM-nucleus interaction - “Migdal Effect”

ER,max = 2µ2

Nv2 max

mN , EEM,max = µNv2

max

2

<latexit sha1_base64="ehW/WUtwMBEd9l2/Njq4sUfIsZg=">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</latexit>

[1607.01789] Energy deposited in nuclear recoil and electromagnetic energy from ionisation:

slide-34
SLIDE 34

Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Rate in Xe

Migdal Rate

34

RED20 module used for EDELWEISS-surf is a true calorimeter - it collects all deposited energy (phonons + EM) - so it can be used to search for these inelastic interactions [1707.07258] Migdal effect has not been measured experimentally, but can be calculated

dR dER dEEM ∼ dR dER d dEe pion.(Ee)

<latexit sha1_base64="sJkIwTR38Oo7jbzk5S0nzLB+9I8=">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</latexit>
  • pion. ∼ 10−4 − 10−2
<latexit sha1_base64="ZLwaQygRplboqoQyTbg0ndyJ9M=">ACD3icbVC7TsMwFHXKq5RXgJHFogKxtEpKJRgrwcBYJPqQmhA5rtNatZPIdpCqKH/Awq+wMIAQKysbf4PTZoCWI1k6Pude3XuPHzMqlWV9G6WV1bX1jfJmZWt7Z3fP3D/oyigRmHRwxCLR95EkjIako6hipB8LgrjPSM+fXOV+74EISaPwTk1j4nI0CmlAMVJa8szT2HM4UmPBU/2vZ9CRlEPbuk9rzQzW5qyReWbVqlszwGViF6QKCrQ98sZRjhJFSYISkHthUrN0VCUcxIVnESWKEJ2hEBpqGiBPprN7MnilSEMIqFfqOBM/d2RIi7lPu6Mt9dLnq5+J83SFRw6aY0jBNFQjwfFCQMqgjm4cAhFQrNtUEYUH1rhCPkUBY6QgrOgR78eRl0m3U7fN647ZbV0XcZTBETgGZ8AGF6AFbkAbdAGj+AZvI348l4Md6Nj3lpySh6DsEfGJ8/KziazQ=</latexit>

Ionise electrons from outer shells with probability:

slide-35
SLIDE 35

Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Migdal Spectra

35

0.03 0.1 1 2 Energy [keV] 102 103 104 105 Number of counts [evts/keV] Migdal Spectra

Background Model Analysis Threshold (60 eV) Data Excluded WIMP model: 50 MeV/c2, 9.0 × 10−29 cm2 Excluded WIMP model: 100 MeV/c2, 7.0 × 10−30 cm2 Excluded WIMP model: 1.0 GeV/c2, 1.6 × 10−32 cm2

slide-36
SLIDE 36

Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

]

2

WIMP Mass [GeV/c

2 −

10

2 −

10 × 2

1 −

10

1 −

10 × 2 1 2 3 4 5 6 7 10 ]

2

WIMP-nucleon cross section [cm

45 −

10

44 −

10

43 −

10

42 −

10

41 −

10

40 −

10

39 −

10

38 −

10

37 −

10

36 −

10

35 −

10

34 −

10

33 −

10

32 −

10

31 −

10

30 −

10

29 −

10

28 −

10

27 −

10

26 −

10

25 −

10

24 −

10

EDELWEISS-Surf (Standard) EDELWEISS-Surf (Migdal) EDELWEISS-III LT CRESST Surface CRESST-II SuperCDMS LT CDMSLite LUX (Standard) LUX (Migdal) XENON1T (Standard) XENON100 LT NEWS-G DarkSide (Standard) XQC CMB Neutrino discovery limit

Migdal Limit - Spin-independent

36

EDELWEISS-surf EDW-surf-Migdal Sensitive down to DM masses of 45 MeV!

slide-37
SLIDE 37

Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

1 −

10 × 2 1 2 3 4 5 6 7 10 20 30 )

2

WIMP Mass (GeV/c

41 −

10

39 −

10

37 −

10

35 −

10

33 −

10

31 −

10

29 −

10

27 −

10

25 −

10

23 −

10 )

2

SD WIMP-Proton Cross Section (cm

EDELWEISS-Surf RRS-Balloon CMB CDMSLite LUX PandaX-II XENON1T PICO-60-II

1 −

10 × 2 1 2 3 4 5 6 7 10 20 30 )

2

WIMP Mass (GeV/c

41 −

10

39 −

10

37 −

10

35 −

10

33 −

10

31 −

10

29 −

10

27 −

10

25 −

10

23 −

10 )

2

SD WIMP-Neutron Cross Section (cm

EDELWEISS-Surf EDELWEISS-Surf Migdal RRS-Balloon XQC CDMSLite LUX PandaX-II XENON1T

Migdal Limit - Spin-dependent

37

WIMP-neutron WIMP-proton EDELWEISS-surf EDELWEISS-surf EDW-surf-Migdal

slide-38
SLIDE 38

Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Migdal Limit - Spin-dependent

38

WIMP-neutron WIMP-proton New results from CRESST surface Li2MoO4 [1902.07587] and underground CaWO4 [1904.00498] Earth-scattering not yet incorporated - SIMP contour calculations underway…

slide-39
SLIDE 39

Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

The future

39

Low-background exposure is underway at Laboratoire Souterrain de Modane, France (alongside continuous EDELWEISS-III exposure) Detectors equipped with electrodes - electric field can amplify the phonon signal due to the Neganov- Trofimov-Luke effect —> even lower threshold With these high performance detectors, it may also be possible to achieve first experimental measurement of the Migdal effect using a neutron calibration source [Credit: Julien Billard]

slide-40
SLIDE 40

Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Coherent Elastic Neutrino Nucleus Scattering (CENNS)

40

CENNS recently observed for the first time by COHERENT collaboration [1708.01294] Low-energy measurements open up powerful probes of New Physics in neutrino sector [Billard, Johnston, BJK - 1805.01798]

Z, Z(?)

<latexit sha1_base64="poeyKL7/vI+W+XeA23jnEmt+vQ=">AB+HicbVBNS8NAEN3Ur1o/GvXoZbEIFaQkVdCbBT14rGA/aBvLZjtl242YXcj1NBf4sWDIl79Kd78N27bHLT1wcDjvRlm5vkRZ0o7zreVWVldW9/Ibua2tnd28/befl2FsaRQoyEPZdMnCjgTUNMc2hGEkjgc2j4o+up3gEqVgo7vU4Ai8gA8H6jBJtpK6db53i1kMnkiwAXLw6doFp+TMgJeJm5ICSlHt2l+dXkjAISmnCjVdp1IewmRmlEOk1wnVhAROiIDaBsqSADKS2aHT/CxUXq4H0pTQuOZ+nsiIYFS48A3nQHRQ7XoTcX/vHas+5dewkQUaxB0vqgfc6xDPE0B95gEqvnYEIlM7diOiSUG2ypkQ3MWXl0m9XHLPSuW780LlJo0jiw7RESoiF12gCrpFVRDFMXoGb2iN+vJerHerY95a8ZKZw7QH1ifP61tkc4=</latexit>
slide-41
SLIDE 41

Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Conclusions

41

]

2

WIMP Mass [GeV/c

2 −

10

2 −

10 × 2

1 −

10

1 −

10 × 2 1 2 3 4 5 6 7 10 ]

2

WIMP-nucleon cross section [cm

45 −

10

44 −

10

43 −

10

42 −

10

41 −

10

40 −

10

39 −

10

38 −

10

37 −

10

36 −

10

35 −

10

34 −

10

33 −

10

32 −

10

31 −

10

30 −

10

29 −

10

28 −

10

27 −

10

26 −

10

25 −

10

24 −

10

EDELWEISS-Surf (Standard) EDELWEISS-Surf (Migdal) EDELWEISS-III LT CRESST Surface CRESST-II SuperCDMS LT CDMSLite LUX (Standard) LUX (Migdal) XENON1T (Standard) XENON100 LT NEWS-G DarkSide (Standard) XQC CMB Neutrino discovery limit

EDELWEISS-surf EDW-surf-Migdal

EDELWEISS-surf achieved a threshold of just 60 eV in a 33.4g Ge detector - low background, underground is underway Small one-day exposure, but very sensitive down to low mass and large cross sections Probing new regions of the spin-independent and spin-dependent parameter space: down to masses of 500 MeV with conventional nuclear recoils and 45 MeV with inelastic signatures Incorporating Earth-shielding effects is essential as we go to lower DM mass and our limits weaken Paves the way for even lower DM masses and for precision measurements of coherent neutrino scattering

slide-42
SLIDE 42

Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Conclusions

42

]

2

WIMP Mass [GeV/c

2 −

10

2 −

10 × 2

1 −

10

1 −

10 × 2 1 2 3 4 5 6 7 10 ]

2

WIMP-nucleon cross section [cm

45 −

10

44 −

10

43 −

10

42 −

10

41 −

10

40 −

10

39 −

10

38 −

10

37 −

10

36 −

10

35 −

10

34 −

10

33 −

10

32 −

10

31 −

10

30 −

10

29 −

10

28 −

10

27 −

10

26 −

10

25 −

10

24 −

10

EDELWEISS-Surf (Standard) EDELWEISS-Surf (Migdal) EDELWEISS-III LT CRESST Surface CRESST-II SuperCDMS LT CDMSLite LUX (Standard) LUX (Migdal) XENON1T (Standard) XENON100 LT NEWS-G DarkSide (Standard) XQC CMB Neutrino discovery limit

EDELWEISS-surf EDW-surf-Migdal

EDELWEISS-surf achieved a threshold of just 60 eV in a 33.4g Ge detector - low background, underground is underway Small one-day exposure, but very sensitive down to low mass and large cross sections Incorporating Earth-shielding effects is essential as we go to lower DM mass and our limits weaken Paves the way for even lower DM masses and for precision measurements of coherent neutrino scattering

Thank you!

Probing new regions of the spin-independent and spin-dependent parameter space: down to masses of 500 MeV with conventional nuclear recoils and 45 MeV with inelastic signatures

slide-43
SLIDE 43

Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Backup Slides

43

slide-44
SLIDE 44

Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Detector Performance

44

slide-45
SLIDE 45

Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Analytic Detector Response

45

10−2 10−1 100 Input Energy [keV] 10−2 10−1 100 Output Energy [keV]

Pulse Simulations (including cuts)

10−2 10−1 100 Input Energy [keV]

Analytic Response (including cuts)

10−3 10−2 10−1 100 101 P(Eout|Ein) [keV−1]

Probability of largest fluctuation within the Optimal Filter window (given ~3 independent samples) POF (X∗|Ein) = 1 √ 2πσ2 exp

  • −(X∗ − Ein)2

2σ2 erf |X∗| √ 2σ (Ns−1) + (Ns − 1) 2 √ 2πσ2 exp

  • −|X∗|2

2σ2 erf |X∗| √ 2σ (Ns−2) erf |X∗| − Ein √ 2σ

  • − erf

− |X∗| − Ein √ 2σ

  • <latexit sha1_base64="H6TCbFMNlviATyaZiFi/z6BKcCw=">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</latexit>
slide-46
SLIDE 46

Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Spin-independent Limits Summary

46

slide-47
SLIDE 47

Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Standard Halo Model

47

Standard Halo Model (SHM) is typically assumed: isotropic, spherically symmetric distribution of particles with . Leads to a Maxwell-Boltzmann (MB) distribution (in the lab frame): ρ(r) ∝ r−2 fLab(v) = (2πσ2

v)−3/2 exp

  • −(v − ve)2

2σ2

v

  • Θ(|v − ve| − vesc)

[But see e.g. 1705.05853]

f(v) = v2

  • f(v) dΩv
slide-48
SLIDE 48

Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Stopping power

48

Consider a detector at a depth of 10.6m, with DM particles coming from directly overhead:

CDMS I at the Stanford Underground Facility [astro-ph/0203500]

Atmosphere Earth Shielding

mχ = 105 GeV σp = 10−28 cm2

slide-49
SLIDE 49

Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

DM-Electron scattering + Monte Carlo

49

[Emken, Kouvaris & Shoemaker -1702.07750] [Emken, Essig, Kouvaris & Sholapurkar - 1905.06348] DM-proton DM-electron

slide-50
SLIDE 50

Bradley J Kavanagh (GRAPPA) LHC Results Forum - 3rd June 2019 Tiny, tough WIMPs with EDELWEISS-surf

Direct Detection Landscape - zoomed out

50

Mack, Beacom & Bertone [0705.4298] Albuquerque & Baudis [astro-ph/0301188]

[BJK - 1712.04901]