hidden photons...hidden photons in beam dump experiments and in connection with dark matter sarah...

Hidden Photons

in Beam Dump Experiments

and in connection with Dark Matter

Sarah AndreasDESY

March 15th, 2013

Workshop to Explore Physics Opportunities with Intense,

Polarized Electron Beams up to 300 MeV

based on: 1209.6083 and 1109.2869

with M. Goodsell, C. Niebuhr, A. Ringwald

Outline

1 Motivation and Introduction

2 Electron Beam Dump Experiments

Production in Bremsstrahlung

Decay & Detection

Beam Dump Limits

3 Hidden Dark Matter

Toy Model

Supersymmetric Model

4 Conclusions

Sarah Andreas (DESY) Hidden Photons & Dark Matter PEB Workshop, 15.03.2013 1 / 18

Motivation & Introduction

Hidden Sector with Hidden Photon

• Hidden Sectors in many BSM scenarios

e.g. string theory, supersymmetry

• simplest scenario: HS with extra U(1)

breaking of large gauge groups yield hidden U(1)s

e.g. heterotic or type II strings, supersymmetric models

hidden photon γ′

couples weakly via kinetic mixing χ with γ

χ generated at loop level: χ ∼ 10−3 − 10−4

• most general Lagrangian

Leff = LSM −1

4XµνX

µν −χ

2XµνF

µν +m2γ′

2XµX

µ + gY jµemAµ

HS

messenger

γ′×

γ

γ′

γ

[Holdom ’86;

Galison, Manohar ’84]


Motivation & Introduction

GeV-scale Dark Force and Dark Matter

• HS can contain matter in addition to gauge fields

⇒ hidden photon as Dark Force

• generates Sommerfeld enhancement,[Arkani-Hamed, Finkbeiner,Slatyer, Weiner ’09]

• allows leptophilic DM annihilation,

⇒ PAMELA & Fermi

• mediates scattering on nuclei

⇒ DAMA, CoGeNT & CRESST

• mass from Higgs or Stuckelberg mechanism

supersymmetric models[Baumgart et al. ’09 and following papers

SA, Goodsell, Ringwald ’11]

large volume string compactifications [Goodsell et al. ’09]

⇒ mγ′ ∼ GeV-scale

DM

γ′×

γ

ψ

ψ

γ′

γ′

γ′

e+

e+

e−

e−


Electron Beam Dump Experiments

Outline


2 Electron Beam Dump ExperimentsProduction in BremsstrahlungDecay & DetectionBeam Dump Limits


4 Conclusions


Electron Beam Dump Experiments Production in Bremsstrahlung

Production

• γ′ emitted from e−-beam

in process similar to ordinary Bremsstrahlung

• production cross section

Weizacker-Williams approximation

(replace target particle N by flux of effective photons Φ(Z))

dσγ′

dxe

me→0'

4 α3 χ2

m2γ′

Φ(Z)

√√√√1−

m2γ′

E2e

(1 +

x2e

3(1− xe )

)

σ ∝α3Z2χ2

m2γ′

' O(10 pb)

compared to e+e− collider case:

σ ∝ α2χ2

E2 ∼ O(10 fb)

e−

e−

γ′

E0 Eγ′ = xeEe

nucleusZ

e+

γ′

e−

E0

e− Eγ′

[Kim, Tsai ’73; Tsai ’74; Tsai ’86;Bjorken, Essig, Schuster, Toro ’09]


Electron Beam Dump Experiments Decay & Detection

Decay

• γ′ can penetrate the dump

carrying most of beam energy

emitted in forward direction

• decay into SM particles

Γγ′→`+`− 'αχ2

3mγ′

• exponential decay with a decay length

lγ′ = γβcτγ′ ∼Eγ′

αχ2m2γ′

∼ 10cmEγ′

1GeV

(10−4

χ

)2(10MeV

mγ′

)2

∼ O(mm− km)

E0

e− Eγ′

γ′ energy

E0 = 1.6 GeV

γ′ emission angle



Detection

• decay must take place within

decay volume to be observable

• detect decay products, mostly e+e−

no SM background (if shield long enough)

• number of expected events from γ′ produced in bremsstrahlung

detected via decay products:

Nevents ∼ Ne nsh

∫dEγ′

∫dEe

∫dl Ie(E0, Ee , l)

dσγ′

dEγ′e−Lsh/lγ′

(1− e

−Ldec/lγ′)

BRe+e−

energy distribution Ie(E0,Ee , l) of electrons in dump has to be taken into account

E0

e− Eγ′



Events in Experiment

• not all events can be detected

geometry of set-up

finite detector size

possibly energy cuts

• compare with events from Monte Carlo simulations

with MadGraph

four-momentum of produced γ′

four-momenta of decay leptons

→ angles, track, energies

⇒ experimental acceptance

[Monte Carlo by Rouven Essig, Philip Schuster, Natalia Toro]

y@c

mD

x @cmD

z @cmD

0100

200

-5 0 5

-5

0

5

Ldec


Electron Beam Dump Experiments Beam Dump Limits

Shape & Experimental Limitations

γ′ has to penetrate O(10 cm) dump

number of events for lγ′ Lsh:

Nevents ∝ e−Lsh/lγ′

lγ′ ∝ Eγ′/χ2 m2

γ′

enough decays within decay volume

number of events for small χ:

Nevents ∝ σ(e−Lsh/lγ′ − e−Ltot/lγ′

)∝ σ

Ldec

lγ′for lγ′ Lsh,dec

∝χ2

m2γ′

χ2m2γ′ Ldec ∝ χ4Ldec

⇒ independent of mγ′

10-2 10-1 1

10-7

10-6

10-5

10-4

10-3

10-2

mΓ' @GeVD

Χ

10-2 10-1 1

10-7

10-6

10-5

10-4

10-3

10-2

mΓ' @GeVD

Χ

e−Lsh/lγ′

10−51

10−1

10-2 10-1 1

10-7

10-6

10-5

10-4

10-3

10-2

mΓ' @GeVD

Χ

e−Lsh/lγ′

10−51

10−1

experimental acceptance

from Monte Carlo simulations

with MadGraph


Electron Beam Dump Experiments Beam Dump Limits

Limits from Experiments

I KEK Japan (1986) [Konaka et al. ’86]

• 27 mC electrons at 2.5 GeV

• shield: 3.5 cm tungsten target, 2.4 m iron

• decay volume: 2.2 m

I Orsay France (1989) [Davier, Nguyen Ngoc ’89]

• 3.2 mC electrons at 1.6 GeV

• shield: 65 cm tungsten target, 1 m lead

• decay channel: 2 m inside concrete wall

I SLAC E141 (1987) [Riordan et al. ’87]

• 0.32 mC electrons at 9 GeV

• shield: 12 cm tungsten; decay volume: 35 m

I SLAC E137 (1988) [Bjorken et al. ’88]

• 30 C electrons at 20 GeV

• shield: alu, 179 m rock; decay volume: 204 m

[SA, Niebuhr, Ringwald]

10-2 10-1 1

10-7

10-6

10-5

10-4

10-3

10-2

mΓ' @GeVD

Χ

KEK

10-2 10-1 1

10-7

10-6

10-5

10-4

10-3

10-2

mΓ' @GeVD

Χ

KEK

Orsay

10-2 10-1 1

10-7

10-6

10-5

10-4

10-3

10-2

mΓ' @GeVD

Χ

KEK

Orsay

E137

E141

E774

10-2 10-1 1

10-7

10-6

10-5

10-4

10-3

10-2

mΓ' @GeVD

Χ

KEK

Orsay

E137

E141

E774SINDRUM

CHARM

NOMAD& PS191

ν-Cal I

ae aµ

K→µνγ′ BaBarKLOE

A1APEX

I Fermilab E774 (1991)

• 0.83 nC electrons at 275 GeV

• shield: 30 cm tungsten

• decay volume: 2 m[Bross et al. ’91]

[Bjorken, Essig, Schuster, Toro ’09]


Hidden Dark Matter

Outline



3 Hidden Dark MatterToy ModelSupersymmetric Model

4 Conclusions


Hidden Dark Matter Toy Model

Toy Model: Dirac fermion DM

Simplest hidden sector with DF & DM

Hidden Photon with mass mγ′ and mixing χ

Additional Dirac fermion ψ

I one extra mass parameter mψ

Relic abundance Ωh2

• annihilation of ψ through and into γ′

• s-channel: resonance for mγ′ = 2 mψ

• t-channel only when mγ′ < mψ

⇒ ψ total DM or subdominant component

[Fayet ’04; Pospelov, Ritz, Voloshin ’08; Cheung, Ruderman, Wang, Yavin ’09; Morrissey,Poland, Zurek ’09; Dudas, Mambrini, Pokorski, Romagnoni ’09; Chun, Park ’10; Essig,Kaplan, Schuster, Toro ’10; Mambrini ’10; Cline, Frey ’12; Hooper, Weiner, Xue ’12]

10-2 10-1 1 10

10-7

10-6

10-5

10-4

10-3

10-2

10-1

mΓ' @GeVD

Χ

10-2 10-1 1 10

10-7

10-6

10-5

10-4

10-3

10-2

10-1

mΓ' @GeVD

Χ

10-2 10-1 1 10

10-7

10-6

10-5

10-4

10-3

10-2

10-1

mΓ' @GeVD

Χ

CoG

eN

T

DAMA

D&C

Einasto

XENON

overabundant

subdom

inant

mDM = 6GeV

[SA, Goodsell, Ringwald ’11]

χ =gY gh16π2 × κ

A1APEX

HPS

DarkLightMESA

WMAP

κ= 10.

WMAP

κ= 0.1


Hidden Dark Matter Toy Model

Toy Model: Dirac fermion DM

Direct Detection

• elastic scattering on nuclei

• mediated by γ′

• spin-independent vector-like interaction

Comparison with experiments

• signal claims from DAMA & CoGeNT

• limits on σSI : XENON10 & 100, DAMIC


10-2 10-1 1 10

10-7

10-6

10-5

10-4

10-3

10-2

10-1

mΓ' @GeVD

Χ

10-2 10-1 1 10

10-7

10-6

10-5

10-4

10-3

10-2

10-1

mΓ' @GeVD

Χ

5 15 25 3510-5

10-4

10-3

10-2

10-1

χ

mγ′ [GeV]

overabundant

κ= 0.1mDM = 6GeV

WMAP

subdom

inant

CoG

eN

T

XENON10


Hidden Dark Matter Supersymmetric Model

Supersymmetric Dark Force models

• most simple anomaly-free HS:

three chiral superfields S , H+, H− charged under U(1)h

superpotential: W ⊃ λS SH+H−

(assume MSSM in visible sector)

• consider gravity mediation gauge med. in [Morrissey, Poland, Zurek ’09]

gravitino is not the LSP

DM can consist of stable hidden sector particle

DM

is either Majorana or Dirac fermion

• hidden gauge symmetry breaking:

radiatively through running

induced by visible sector




Radiative breaking

• running of Yukawa coupling λS induces breaking

choose masses & couplings at high scale

• Majorana fermion ΨM: total & subdominant DM

axial coupling generates SD scattering

minor SI scattering (Higgs Portal ∼ 10−46cm−2)

5 15 25 3510-5

10-4

10-3

10-2

10-1

5 10 1510-41

10-39

10-37

5 10 1510-41

10-39

10-37

5 10 1510-48

10-46

10-44

10-42

10-40

mDM [GeV]mγ′ [GeV]

χ

σSI

p[cm

2]

σSD

n[cm

2]

σSD

p[cm

2]


0.1≤κ≤10

SIMPLE

XENON100

PICASSO

COUPP

ΨM

SD

XENON100

XENON10

ZeplinCDMS

ΨM

SD

XENON100

XENON100

XENON10CDMS

ΨMSI

⇒ SD in reach of experiments SI bejond reach



Visible sector induced breaking

• via effective Fayet-Iliopoulos term

assume gravitino heavier than HS

• Majorana & Dirac fermion as DM

ΨM: mostly SD (like rad. breaking)

ΨD: mostly SI (like Toy-Model, but mΨ < mγ′ )

5 15 25 3510-4

10-3

10-2

10-1

5 15 25 3510-41

10-39

10-37

5 15 25 3510-41

10-39

10-37

5 15 25 35

10-47

10-45

10-43

10-41

10-39

10-37

0.1≤κ≤10

mγ′ [GeV]

χ

SD probe ΨM⇒ SI probe ΨD[SA, Goodsell, Ringwald ’11]

mDM [GeV]σSI

p[cm

2]

σSD

n[cm

2]

σSD

p[cm

2]

SIMPLE

XENON100

PICASSO

COUPP

ΨMSD

XENON100

XENON10

Zeplin

CDMS

ΨMSD

DAMIC

XENON100

XENON100

XENON10CDMS

ΨD

ΨMSI

10-2 10-1 1

10-5

10-4

10-3

10-2

mγ′ [GeV]

χ


Conclusions

Outline




4 Conclusions


Conclusions

Conclusions

• hidden sector

well motivated, in many BSM scenarios

• hidden photons as dark force

need high intensity experiments, e.g. beam dumps

constrained and currently further explored

• dark matter in HS

viable as total & subdominant DM with potential for DD

SUSY models with gravity mediation

yield Majorana or Dirac fermion as viable DM candidates


hidden photons...hidden photons in beam dump experiments and in connection with dark matter sarah...

Documents