Antideuteron Signatures of Dark Matter with the GAPS ... · PDF fileAntideuteron Signatures of Dark Matter with the ... Haverford College/Columbia University U. Chicago HEP Seminar

Antideuteron Signatures of Dark Matter with the

GAPS Experiment

Kerstin Perez Haverford College/Columbia University

U. Chicago HEP Seminar

February 16, 2015

2

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 •  …

3

Dark Matter and WIMPs


•  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

4

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 •  …


5


The$Large$Hadron$Collider$

Beyond the Standard

Model (BSM) Physics

Standard Model

Standard Model

Dark Matter

Dark Matter

Par1cle$Colliders$


6



Beyond the Standard

Model (BSM) Physics

Standard Model

Standard Model

Dark Matter

Dark Matter

Direct$Detec1on$

Par1cle$Colliders$LUX$


7



Par1cle$Colliders$

Direct$Detec1on$

Indirect$Detec1on$

Beyond the Standard

Model (BSM) Physics

Standard Model

Standard Model

Dark Matter

Dark Matter

AMS$

LUX$


8 K. Perez - Haverford/Columbia

•  Introduction

•  Antideuteron signatures of Dark Matter •  Antideuteron search compatibility




9

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


GAPS and Antideuterons A generic dark matter signature with essentially zero conventional

astrophysical background


Coalescence and Hadronization Models


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

K. Perez - Haverford/Columbia 12

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


•  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).


•  Introduction


•  Antideuteron search compatibility •  The General Antiparticle Spectrometer (GAPS)

Experiment




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)%


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


•  Introduction





•  The future!

The GAPS Team

18 K. Perez - Haverford and Columbia U.

19

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<$


20

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<$


d" d"d" d"

21

GAPS Background Rejection

Combination of time-of-flight + depth-sensing, X-ray, and π detection yield rejection >105


22

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


1.6 m 1.6 m


•  Introduction




•  The prototype GAPS balloon flight •  The future!

24

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


The pGAPS Instrument


The pGAPS Flight

Taiki, Japan


Liftoff! 4:55 am

Float%al*tude%=%~33%km%10:22%am%

Recovery%11:45%am%



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


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


•  Introduction






31

Homemade Si(Li) Detectors GAPS will need ~1300 Si detectors!



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


Lithium drifted Silicon detectors Lithium ions compensate impurities in boron-doped Si, creating

extended charge-free regions


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



“pGtype”%doped%wafer%

• %free%posi*ve%hole%• %fixed%nega*ve%ion%

B$

Si$ Si$ Si$

Si$

Si$Si$Si$

Si$



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%





• %high%temperature,%~110%C%• %constant%voltage,%~500%V%• %long%*me,%~90%hrs%for%2.5%mm%

E Li%driY%







E Li%driY%







E Li%driY%

Extended%chargeGfree%region!%With%strips%

and%guard%ring%



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


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!

42

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%


43

Why Antarctica?


44

Why Antarctica?


Thank you!


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Antideuteron Signatures of Dark Matter with the GAPS ... · PDF fileAntideuteron Signatures of Dark Matter with the ... Haverford College/Columbia University U. Chicago HEP Seminar