hidden photons in beam dump experiments · april 26th, 2013 intensity frontier workshop based on:...

Hidden Photons

in Beam Dump Experiments

and in connection with Dark Matter

Sarah AndreasDESY

April 26th, 2013

Intensity Frontier Workshop

based on: 1209.6083 and 1109.2869

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

Outline

1 Introduction

2 Electron Beam Dump Experiments

Production in Bremsstrahlung

Decay & Detection

Beam Dump Limits

3 Hidden Dark Matter

Toy Model

Supersymmetric Model

4 Conclusions & Outlook

Sarah Andreas (DESY) e–Beam Dumps & Dark Matter Intensity Frontier, 26.04.2013 1 / 21

Introduction

Hidden Sector with Hidden Photon

• Hidden Sectors in many BSM scenariose.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′ with kinetic mixing χ

• most general Lagrangian� χ generated at loop level: χ ∼ 10−3 − 10−4

� hidden photon mass mγ′ ∼ GeV

HS

γ′×γ

γ′

γ

[Holdom ’86;

Galison, Manohar ’84]

L ⊃ − 14XµνXµν +

χ2XµνFµν +

12m2γ′XµX

µ


Electron Beam Dump Experiments Production in Bremsstrahlung

Production

• γ′ emitted from e−-beamin process similar to ordinary Bremsstrahlung

• production cross sectionWeizäcker-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 ∝ α3Z2 χ2

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 withindecay 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 bremsstrahlungdetected 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 simulationswith 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 05

-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 ∝ Ne e−Lsh/lγ′

lγ′ ∝ Eγ′/χ2 m2γ′

enough decays within decay volume

number of events for small χ:

Nevents ∝ Ne σ(e−Lsh/lγ′ − e−Ltot/lγ′

)∝ Ne σ

Ldec

lγ′for lγ′ � Lsh,dec

∝ Neχ2

m2γ′

χ2m2γ′ Ldec ∝ Ne χ4Ldec

⇒ independent of mγ′

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











)∝ Ne σ

Ldec


∝ Neχ2

m2γ′



10-2 10-1 1

10-7

10-6

10-5

10-4

10-3

10-2

mΓ' @GeVD

Χ

experimental acceptance

from Monte Carlo simulations

with MadGraph











)∝ Ne σ

Ldec


∝ Neχ2

m2γ′



10-2 10-1 1

10-7

10-6

10-5

10-4

10-3

10-2

mΓ' @GeVD

Χ



with MadGraph

10-2 10-1 1

10-7

10-6

10-5

10-4

10-3

10-2

mΓ' @GeVD

Χ

+

−

E0

−

+

Lsh

factor 4











)∝ Ne σ

Ldec


∝ Neχ2

m2γ′



10-2 10-1 1

10-7

10-6

10-5

10-4

10-3

10-2

mΓ' @GeVD

Χ



with MadGraph

10-2 10-1 1

10-7

10-6

10-5

10-4

10-3

10-2

mΓ' @GeVD

Χ

−

+ Ldec

factor 5











)∝ Ne σ

Ldec


∝ Neχ2

m2γ′



10-2 10-1 1

10-7

10-6

10-5

10-4

10-3

10-2

mΓ' @GeVD

Χ



with MadGraph

10-2 10-1 1

10-7

10-6

10-5

10-4

10-3

10-2

mΓ' @GeVD

Χ

−

+ Ne

factor 10



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

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

1 Introduction


3 Hidden Dark MatterToy ModelSupersymmetric Model



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

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.




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

overabundant

subdom

inant

mDM = 6GeV


χ =gY gh16π2

× κ

WMAP

κ= 0.1




Direct Detection

• elastic scattering on nuclei• mediated by γ′

• spin-independent vector-like interaction

Comparison with experiments

• signal claimsby DAMA, CoGeNT, CRESST, CDMS

• 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

5 15 25 3510-5

10-4

10-3

10-2

10-1

χ

mγ′ [GeV]

overabundant

κ= 0.1mDM = 6GeV

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

ΨM SI

⇒ SD in reach of experiments SI bejond reachSarah Andreas (DESY) e–Beam Dumps & Dark Matter Intensity Frontier, 26.04.2013 18 / 21


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 & Outlook

Outline

1 Introduction


3 Hidden Dark Matter





10-2 10-1 1

10-7

10-6

10-5

10-4

10-3

10-2

mΓ' @GeVD

Χ

• electron beam dump experiments� cover lower left corner of the parameter space

� extending the limits

. upwards requires short Lsh and/or high E0

. downwards requires long Ldec and/or large Ne

? which electron beams are available in the future?

? can they be used parasitically for new bounds?

• dark matter in hidden sector� viable models with large parameter space

� SUSY models with gravity mediation also possible

? what is the preferred parameter space?

? constraints from indirect detection?


IntroductionElectron Beam Dump ExperimentsProduction in BremsstrahlungDecay & DetectionBeam Dump Limits

Hidden Dark MatterToy ModelSupersymmetric Model


hidden photons in beam dump experiments · april 26th, 2013 intensity frontier workshop based on:...

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