Antideuteron Signatures of Dark Matter with the GAPS ...
Transcript of Antideuteron Signatures of Dark Matter with the GAPS ...
Antideuteron Signatures of Dark Matter with the
GAPS Experiment
Kerstin Perez Haverford College/Columbia University
U. Chicago HEP Seminar
February 16, 2015
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Outline
• Introduction
• Antideuteron signatures of Dark Matter
• Antideuteron search compatibility
• The General Antiparticle Spectrometer (GAPS) Experiment
• The prototype GAPS balloon flight
• Si(Li) detectors and the future!
K. Perez - Haverford/Columbia
• Searches focus on WIMPs (Weakly Interacting Massive Particles), axions, … • gravitational interactions • no strong, no electromagnetic force • non-relativistic
• Fermi, PAMELA, AMS-02 – e+
• Fermi - γ-rays from Galactic Center • DAMA, CDMS, … – low-E scattering • …
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Dark Matter and WIMPs
K. Perez - Haverford/Columbia
• Astronomical evidence points toward 5x more DM than baryonic matter in the Universe
Tantalizing possible detections! But vulnerable to variations in background predictions
d̄ give an astrophysical background-free signature
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Searching for Dark Matter
Beyond the Standard
Model (BSM) Physics
Standard Model
Standard Model
Dark Matter
Dark Matter
• Supersymmetry • Kaluza-Klein • Grand Unified theories (GUT) • …
• photons • p, n, e-, μ • antimatter:
• e+, p, He • …
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Searching for Dark Matter
The$Large$Hadron$Collider$
Beyond the Standard
Model (BSM) Physics
Standard Model
Standard Model
Dark Matter
Dark Matter
Par1cle$Colliders$
K. Perez - Haverford/Columbia
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Searching for Dark Matter
The$Large$Hadron$Collider$
Beyond the Standard
Model (BSM) Physics
Standard Model
Standard Model
Dark Matter
Dark Matter
Direct$Detec1on$
Par1cle$Colliders$LUX$
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Searching for Dark Matter
The$Large$Hadron$Collider$
Par1cle$Colliders$
Direct$Detec1on$
Indirect$Detec1on$
Beyond the Standard
Model (BSM) Physics
Standard Model
Standard Model
Dark Matter
Dark Matter
AMS$
LUX$
K. Perez - Haverford/Columbia
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• Introduction
• Antideuteron signatures of Dark Matter • Antideuteron search compatibility
• The General Antiparticle Spectrometer (GAPS) Experiment
• The prototype GAPS balloon flight
• Si(Li) detectors and the future!
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Antideuteron Signal of Dark Matter
Beyond the Standard
Model (BSM) Physics
W, Z, H, quark…
p
n D$
Dark Matter
Dark Matter
p, n, π, …
Dark%ma'er%par*cles%annihilate…%
…create%jets%of%Standard%Model%
par*cles…%
…some%of%which%can%make%an%%
an*deuteron…%H
adro
niza
tion
Coal
esce
nce
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GAPS and Antideuterons A generic dark matter signature with essentially zero conventional
astrophysical background
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Coalescence and Hadronization Models
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Coalescense: n̄ and p,̄ merge when relative momentum < p0 To determine p0: 1. Assume uncorrelated, isotropic
distribution of n̄ and p ̄2. MC method that accounts for
correlations due to production channel or center-of-mass energy
3. MC method with additional Δr requirement
Then tune this to experimental data: e+e- ! d ̄data from LEP All depends on choice of
hadronization model!
Choice of coalescence and hadronization model affects
d ̄sensitivity by factors of ~3-4
p, n, π, …
n̄
p̄̄
W, Z, H, quark…
D$
Had
roni
zatio
n
Coal
esce
nce
0.1 1 1010−8
10−7
10−6
10−5
10−4 bb channel − mDM = 100 GeV
T [GeV/n]
φ d [(
m2 s
sr G
eV/n
)−1 ]
GAPSLDB+ AMS
MINMEDMAX
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Propagation Model Galactic:
• Largest source of uncertainty on d ̄ flux!
Halo
Disk • diffusion • convection • annihilation • size of halo • size of disk
Fornengo, Maccione, Vittino (2013).
Solar: • Magnetic field changes on timescales of ~11 year
200 400 600 800 10000.1
1
10
100
1000
Mx!(GeV)!
Number!o
f!D!|"
LDB+"LDB"
Rare Event Search
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• Analogy to direct search experiments:
• handful of signal events • instrument background dominated • long integration times • multiple technologies
MAX propagation
MED propagation
Small expected signal flux and multiple uncertainties highlight need for many experiments,
complementary sensitivities
Neutralino fluxes from Cui, Mason, and Randall, J. High Energy Phys. 11, 017 (2010).
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• Introduction
• Antideuteron signatures of Dark Matter
• Antideuteron search compatibility • The General Antiparticle Spectrometer (GAPS)
Experiment
• The prototype GAPS balloon flight
• Si(Li) detectors and the future!
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Sensitive to Viable Light and Heavy DM
GAPS
Brauninger and Cirelli (2009)
• Sensitive to low-mass DM models, as invoked to explain CDMS-II Si, COGENT, Fermi observations
• Sensitive to heavy DM models, as invoked to explain PAMELA, AMS observations of positron excess
Donato,%Fornengo,%Maurin%(2008)%
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Provides Precision Antiproton Measurement
Kinetic energy [GeV]-110 1
]-1
s S
r GeV
)2
Ant
ipro
ton
flux
[(m
-310
-210
BESS 95/97BESS-Polar IIPAMELA
GAPS
neutralino, m = 8 GeVLZP, m = 30 GeVgravitino, m = 100 GeVPBH,
R = 1.2 x 10-3pc-3yr-1
secondaryneutralino+secondary
• GAPS will measure ~1500 antiprotons per flight, in the unprecedented E <0.25 GeV/n energy range
• Sensitive to signals that evade higher-energy experiments, e.g.
• light neutralinos • LZPs • gravitinos • primordial black holes
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• Introduction
• Antideuteron signatures of Dark Matter
• Antideuteron search compatibility
• The General Antiparticle Spectrometer (GAPS) Experiment
• The prototype GAPS balloon flight
• The future!
The GAPS Team
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GAPS Detection Concept
T. Aramaki et al., http://arxiv.org/abs/1303.3871
• Time-of-flight system measures velocity • Loses energy in layers of semiconducting
Silicon targets/detectors • Stops, forming exotic excited atom • Atom de-excites, emitting x-rays • Remaining nucleus annihilates, emitting
pions and protons %
Si$ D$
e<$
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GAPS Detection Concept
d" d"
T. Aramaki et al., http://arxiv.org/abs/1303.3871
• Time-of-flight system measures velocity • Loses energy in layers of semiconducting
Silicon targets/detectors • Stops, forming exotic excited atom • Atom de-excites, emitting x-rays • Remaining nucleus annihilates, emitting
pions and protons %
Si$ D$
e<$
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d" d"d" d"
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GAPS Background Rejection
Combination of time-of-flight + depth-sensing, X-ray, and π detection yield rejection >105
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GAPS Detector Design Plastic scintillator TOF • high-speed trigger and veto • 160-180 cm long, 0.5 cm thick • read out both ends • ~500 ps timing resolution
Si(Li) targets/detectors • X-ray identification, dE/dx, stopping depth, and shower particle multiplicity • 2.5 mm thick, 4” (or 2”) diameter • 4 keV resolution for X-rays
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1.6 m 1.6 m
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• Introduction
• Antideuteron signatures of Dark Matter
• Antideuteron search compatibility
• The General Antiparticle Spectrometer (GAPS) Experiment
• The prototype GAPS balloon flight • The future!
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pGAPS: a Prototype GAPS Flight
100% of flight goals met!
(1) verify%stable,%lowGnoise%opera*on%of%Si(Li)%detectors%at%ambient%flight%pressure%
(2) validate%the%cooling%system%and%thermal%model%for%the%Si(Li)%system%
(3) measure%the%background%levels%at%flight%al*tude%to%validate%simula*on%codes
TOF
TOF
TOF
4”-diameter Si(Li)
S. A. I. Mognet, et al. (2013) arXiv:1303.1615
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The pGAPS Instrument
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The pGAPS Flight
Taiki, Japan
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Liftoff! 4:55 am
Float%al*tude%=%~33%km%10:22%am%
Recovery%11:45%am%
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pGAPS Cooling Results
Cooling performance confirms thermal model
• With proper pointing, cooling system allows optimal Si(Li) operation • Oscillating heat pipe (OHP) system also validated with thermal simulation
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pGAPS Detector Results ENGR. DRAWN D.STEFANIK DATE 02-20-12 ISSUE
COLUMBIA
UNIVERSITY
X-RAY TUBEPLACEMENT
SCALE
DIMENSION ARE IN MM[ENGLISH]SIZE OF PART SHALL BE HELD AS FOLLOWS:TO 2 DECIMAL PLACES .13 AS ANGLE -TO 3 PLACES .010
MATERIAL: FINISH
X-RAY BEAM 45 INCLUDED ANGLE60 ANGLE FROM TUBE
Si(Li) resolution consistent with temperature-dependent predictions
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• Introduction
• Antideuteron signatures of Dark Matter
• Antideuteron search compatibility
• The General Antiparticle Spectrometer (GAPS) Experiment
• The prototype GAPS balloon flight
• Si(Li) detectors and the future!
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Homemade Si(Li) Detectors GAPS will need ~1300 Si detectors!
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Why Si(Li) Detectors? ATLAS Si pixel module
~2 c
m
~6 cm
• 46,080 channels per module • 50 x 400 μm pixel (typical) • 250 μm thick • Delivers spatial resolution
10µm in r-φ, 115µm in z (or r)
GAPS Si(Li) detector
~10 cm
• 4 channels per module • ~2.5 cm wide strip • 2.5 mm thick • Delivers stopping power to
capture d ̄ up to 0.25 GeV/n, energy resolution < 4 keV to distinguish X-rays, spatial resolution sufficient to distinguish X-rays, annihilation products, incident cosmic rays
• Low cost fabrication
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Lithium drifted Silicon detectors Lithium ions compensate impurities in boron-doped Si, creating
extended charge-free regions
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Lithium drifted Silicon detectors
“pGtype”%doped%wafer%
• %free%posi*ve%hole%• %fixed%nega*ve%ion%
B$
Si$ Si$ Si$
Si$
Si$Si$Si$
Si$
Lithium ions compensate impurities in boron-doped Si, creating extended charge-free regions
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Lithium drifted Silicon detectors
“pGtype”%doped%wafer%
• %free%posi*ve%hole%• %fixed%nega*ve%ion%
B$
Si$ Si$ Si$
Si$
Si$Si$Si$
Si$
Lithium ions compensate impurities in boron-doped Si, creating extended charge-free regions
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Lithium drifted Silicon detectors Lithium ions compensate impurities in boron-doped Si, creating
extended charge-free regions
“pGtype”%doped%wafer% • %free%posi*ve%hole%• %fixed%nega*ve%ion%
Li%“nGtype”%layer% • %free%electron%• %mobile%posi*ve%ion%
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Lithium drifted Silicon detectors
“pGtype”%doped%wafer% • %free%posi*ve%hole%• %fixed%nega*ve%ion%
Li%“nGtype”%layer% • %free%electron%• %mobile%posi*ve%ion%
• %high%temperature,%~110%C%• %constant%voltage,%~500%V%• %long%*me,%~90%hrs%for%2.5%mm%
E Li%driY%
Lithium ions compensate impurities in boron-doped Si, creating extended charge-free regions
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Lithium drifted Silicon detectors
“pGtype”%doped%wafer% • %free%posi*ve%hole%• %fixed%nega*ve%ion%
Li%“nGtype”%layer% • %free%electron%• %mobile%posi*ve%ion%
• %high%temperature,%~110%C%• %constant%voltage,%~500%V%• %long%*me,%~90%hrs%for%2.5%mm%
E Li%driY%
Lithium ions compensate impurities in boron-doped Si, creating extended charge-free regions
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Lithium drifted Silicon detectors
“pGtype”%doped%wafer% • %free%posi*ve%hole%• %fixed%nega*ve%ion%
Li%“nGtype”%layer% • %free%electron%• %mobile%posi*ve%ion%
• %high%temperature,%~110%C%• %constant%voltage,%~500%V%• %long%*me,%~90%hrs%for%2.5%mm%
E Li%driY%
Extended%chargeGfree%region!%With%strips%
and%guard%ring%
Lithium ions compensate impurities in boron-doped Si, creating extended charge-free regions
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Si(Li) Detector Fabrication
Cu]ng% DriYing% Etching%
In-house facility at CU/DTU-NSC!!
They are ready to go!!
Li evaporation and diffusion
Ultrasonic impact grinding
Chemical etching
Li drifting station LN2-cooled testing system
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Si(Li) Detector Performance
Voltage [V]-200 -150 -100 -50 0
Leak
age
curr
ent [
nA]
0
10
20
30
40
50
60 -45 C-32 C-28 C-23 C-18 C
-45 C-32 C-28 C-23 C-18 C
Resolution measured with an Am-241 X-ray source
Operational temperature range for 1 mm thick prototype detector
2”-diameter, 1 mm thick prototype detectors have been produced with the required performance!
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The Future of GAPS
Detector%produc*on%and%calibra*on%Data%acquisi*on%and%calibra*on%soYware%%
Full%instrument%construc*on%
First$Antarc1c$flight!$
2000$
2019$
2004$
2012$
2008$
First%idea%
KEK%beam%tests%
Design%and%sensi*vity%studies%Technical%valida*on%
pGAPS%engineering%flight%
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Why Antarctica?
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Why Antarctica?
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Thank you!
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