T H E I M PA C T O F E A R T H S C AT T E R I N G S O N L I G H - - PowerPoint PPT Presentation

T H E I M PA C T O F E A R T H S C AT T E R I N G S O N L I G H T D A R K M AT T E R D E T E C T I O N

T I M O N E M K E N ( C P ³ - O R I G I N S , O D E N S E )

Based on: [arXiv:1706.02249]* [arXiv:1802.04764]* [arXiv:180?.????]**

* In collaboration with Chris Kouvaris. ** In collaboration with Rouven Essig, Chris Kouvaris, and Mukul Sholapurkar.

24.04.2018 C.N. Yang Institute for Theoretical Physics

Hasenbalg et al, Phys.Rev. D55 (1997) 7350-7355 Starkman et al, Phys.Rev. D41 (1990) 3594 TE, C. Kouvaris, [arXiv:1802:04764]

0.1 0.5 1 5 10 10-47 10-42 10-37 10-32 10-27 10-22

CRESST 2017 surface CRESST III C R E S S T I I DAMIC(2011) XQC CMB XENON1T n e u t r i n

• b

a c k g r

• u

n d

• Pre-detector Earth

scatterings affect the expected signal.

1.Diurnal modulations 2.Loss of sensitivity

O U T L I N E

• I. Terrestrial DM-nucleus scatterings
• II. Monte Carlo simulation of DM trajectories
• III. Implications for direct detection
• Diurnal modulations
• Earth shielding
• IV. DM-electron scattering experiments

T E R R E S T R I A L D M - N U C L E U S S C AT T E R I N G S

Part I

R E L E VA N C E O F E A R T H S C AT T E R I N G S

L ⊃ gX ¯ XγµXA0

µ + εFµνF 0µν + m2 φA0 µA0µ

σχp σχe ' ✓µχp µχe ◆2

• unobservable underground DM-nucleus scatterings
• ccur frequently for O(pb) cross sections.
• these change the DM phase space inside the Earth
• Look e.g. at models with a heavy dark photon portal
• Here tested DM-electron cross sections are

accompanied by strong DM-nucleus interactions.

S.K. Lee et al, PRD92 (2015) 083517 TE, C. Kouvaris, I. Shoemaker, PRD96 (2017) no.1, 015018

D A R K M AT T E R S C AT T E R I N G I N S I D E T H E E A R T H

P(L) = 1 − exp  − Z dx MFP(~ x,~ v)

• Probability to scatter after travelling a distance L:
• The mean free path is given by
• Underground DM-nucleus scatterings have two consequences:
• A. re-distribution of DM particles inside the Earth
• B. deceleration of the DM particles
• If DM-nucleus interactions are sufficiently strong, these two effects could

influence the outcome of a DM detection experiment severely.

−1

MFP(~

x,~ v) = X

i

fAi(~ x)⇢⊕(~ x) mAi total

χAi (~

v)

M O N T E C A R L O S I M U L AT I O N S O F D A R K M AT T E R T R A J E C T O R I E S

Part II

M C S I M U L AT I O N S

J.I. Collar, F.T. Avignone, Phys. Lett. B275 (1992), 181-185 J.I. Collar, F.T. Avignone, PRD 47 (1993), 5238-5246 Hasenbalg et al., PRD 55 (1997), 7350-7355

• Isodetection angle

Θ(t) = arccos  ~ v⊕(t) · ~ xlab(t) v⊕(t)(r⊕ − dlab)

E A R T H S H A D O W

B.J. Kavanagh, R. Catena, C. Kouvaris, JCAP 1701 (2017) no 01, 012

An analytic treatment of single Earth scatterings.

• Limited to scattering probabilities of ≤10%.
• The EarthShadow code is public:

https://github.com/bradkav/EarthShadow

M C S I M U L AT I O N V S E A R T H S H A D O W

A C R U C I A L C O N S I S T E N C Y C H E C K

R E S U LT S : D M S P E E D D I S T R I B U T I O N S

180 150 120 90 60 30 180 150 120 90 60 30 180 150 120 90 60 30 180 150 120 90 60 30

TE,C. Kouvaris, JCAP 1710 (2017) no.10, 031

I M P L I C AT I O N S F O R D I R E C T D E T E C T I O N

Part III

E V E N T R AT E A C R O S S T H E G L O B E

D I U R N A L M O D U L AT I O N

D I U R N A L M O D U L AT I O N

δ(Φlab) = 100 Rmax − Rmin Rmax

• We can predict the

local diurnal modulation for every laboratory.

• Both amplitude and

phase.

• Different experiments

could be cross- correlated.

D I U R N A L M O D U L AT I O N

W H E N T E R R E S T R I A L D E T E C T O R S L O S E S E N S I T I V I T Y

Part III.b

Atmosphere Earth crust Lead shielding Detector

D A R K M AT T E R S T O P P I N G P O W E R W I T H O U T M C

• DM traversing through matter lose energy:
• Method A: Find cross section, for which the
• verburden makes even the fastest particles

undetectable.

• Method B: Compute the change of the DM spectrum

dhEi dx = X

i

ni(x)

Emax

R

Z dER ER dσi dER dR dER = nDMnT

∞

Z

vmin(ER)

dv vf(v) dσi dER

J.H. Davis, Phys.Rev.Lett. 119 (2017) no.21, 211302 B.J. Kavanagh, [arXiv:1712.04901]

D M S H I E L D I N G B Y T H E E A R T H C R U S T

0.1 0.5 1 10-46 10-44 10-42 10-40 10-38 10-36 10-34 10-32 10-30 10-1 102 105 108 1011 1014

M.S. Mahdawi, G.R. Farrar, JCAP 1712 (2017) 004 TE,C. Kouvaris, [arXiv:1802:04764]

D M - N U C L E U S C O N S T R A I N T S

0.1 0.5 1 5 10 10-47 10-42 10-37 10-32 10-27 10-22

CRESST 2017 surface CRESST III C R E S S T I I DAMIC(2011) XQC CMB XENON1T n e u t r i n

• b

a c k g r

• u

n d

D M - E L E C T R O N S C AT T E R I N G E X P E R I M E N T S

Part IV

D M - E L E C T R O N E X P E R I M E N T S

S.K. Lee et al, PRD92 (2015) 083517 TE, C. Kouvaris, I. Shoemaker, PRD96 (2017) no.1, 015018

2000 4000 6000 8000 10000 12000

• 1500
• 1000
• 500

#

• []

χ=

107 g-d,11 e- 100 g-yr, 2e-(proj.)

• 1

5 10 50 100 5001000 10-41 10-38 10-35 10-32 10-29 10-26

[]

• σ- []

σχp σχe ' ✓µχp µχe ◆2

• Models with heavy dark photon

portal and kinetic mixing:

• Testable DM-electron cross

sections are connected to very strong, but unobservable DM- nucleus interactions.

• In the most extreme case these

could “blind" a detector.

D M E L E C T R O N E X P E R I M E N T S

• Implement the full computation of event rates for liquid noble gas

experiments and semiconductor targets (ionization and crystal form factors).

• Main focus lies on light mediators

➡ new q-dependence in the cross section alter the scattering kinematics and stopping power of the overburden ➡ IR divergencies and charge screening for small momentum transfers (relevant for DM masses below ~10 MeV)

• Use both analytic and MC methods.
• R. Essig et al., JHEP 1605 (2016) 046
• R. Essig et al., Phys.Rev. D96 (2017) no.4, 043017

DarkSide collaboration, [arXiv:1802:06998]

What’s new?

S C AT T E R I N G D Y N A M I C S W I T H L I G H T M E D I AT O R S

• 1.0
• 0.5

0.0 0.5 1.0 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

cos α fN(cos α) FDM=1

• 1.0
• 0.5

0.0 0.5 1.0 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

cos α fN(cos α) FDM~ 1

q

• 1.0
• 0.5

0.0 0.5 1.0 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

cos α fN(cos α) FDM~ 1

q2

v=50 km

sec

v=300 km

sec

v=vesc+v⊕

mDM = 1 MeV mDM = 10 MeV mDM = 100 MeV mDM = 1000 MeV

FA(q) = a2q2 1 + a2q2

D M F O R M FA C T O R V S C H A R G E S C R E E N I N G

FDM(q) = 8 > > < > > : 1 , for heavy mediator ,

qref q ,

for ED interaction , ⇣

qref q

⌘2 , for light mediator .

P R E L I M I N A RY R E S U LT S

100 101 102 103 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 10-23

mχ[MeV] σe[cm2] FDM=1

100 101 102 103 104 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

mχ[MeV] σe[cm2] FDM=αme/q

100 101 102 103 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 10-23 10-22

mχ[MeV] σe[cm2] FDM=(αme/q)2 XENON10 XENON100 SENSEI DarkSide-50 SuperCDMS(2018)

P R E L I M I N A R Y P R E L I M I N A R Y

Further experiments: DarkSide-50 & SuperCDMS Projections for e.g. high-altitude experiments. better understanding on electronic stopping power

To Do

D A M A S C U S

D a r k M a t t e r S i m u l a t i o n C o d e f o r U n d e rg ro u n d S c a t t e r i n g s

The code is public:

http://github.com/temken/

Thank you!

B A C K U P :

M O D E L L I N G T H E E A R T H

• Density Profile: Preliminary

Reference Earth Model (PREM)

• Composition: Two compositional

layers (core & mantle)

A.M. Dziewonski et al, Physics of the Earth and Planetary Interiors 25 (1981) 297-356

• W. McDonough, Treatise on Geochemistry, vol. 3,

559-577. Elsevier, 2014 [1312.1202]

Element Core[%] Mantle[%] Element Core[%] Mantle[%]

56Fe

85.5 6.26

32S

1.9 0.03

16O

44

52Cr

0.9 0.26

28Si

6 21

23Na

0.27

24Mg

22.8

31P

0.2 0.009

58Ni

5.2 0.2

55Mn

0.3 0.1

40Ca

2.53

12C

0.2 0.01

27Al

2.35

1H

0.06 0.01 Total 100.26 99.83

B A C K U P :

I N I T I A L C O N D I T I O N S

• Initial velocity:
• Initial position:

fhalo(~ v) = 1 Nesc exp ✓ −~ v2 v2 ◆ Θ(vesc − |~ v|)

~ vini = ~ vhalo − ~ v⊕(t) ~ rini = R~ ez + p ⇠r⊕ (cos ~ ex + sin ~ ey)

M C A L G O R I T H M

B A C K U P : D A R K M AT T E R T R A J E C T O RY S I M U L AT I O N

START Initial Conditions (ti,~ ri,~ vi) Enter Earth? Save (tf,~ rf,~ vi).

No.

Save point of entry (tentry,~ rentry,~ vi).

Yes.

Determine free displacement ~ ∆. New position: ~ ri+1 = ~ ri + ~ ∆ Still under- ground? (|~ ri+1| < r⊕?) Save point of exit (texit,~ rexit,~ vi) and a fi- nal position (tf,~ rf,~ vi)

• utside the earth.

No.

STOP

The particle scatters: Find scatter nucleus, calculate ~ vi+1 and save (ti+1,~ ri+1,~ vi+1). Yes.

Is |~ v| ≥ vcutoff?

i → i + 1 Yes. No.

• Every time a particle

passes an isodetection ring, we record its velocity.

• Repeat simulation

until we have sufficient velocity data for each ring.

• Estimate the local

velocity distributions, e.g. with histograms.