Some model-independent phenomenological consequences

of flexible brane-worlds

IRGAC 2006

                                                        

                                      

Barcelona, July 11-15 2006

J.A.R. CembranosA. Dobado

A. L. Maroto

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• Brane worlds: branons vs. KK gravitons • Phenomenology in colliders

• Branons as dark matter

• Virtual branon effects

Summary

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• Brane worlds: branons vs. KK gravitons

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Introduction: brane worlds

Rfundamental scale

of gravity in D = 4 + dimensions

brane tension

Brane universe

Brane hierarchy

MD f4

ADD, 98Antoniadis, et al. 98

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Kaluza-Klein gravitons

3+1 coordinates extra-dimensional coordinates

KK gravitontower

Linearizing the bulkgravitational field

KK gravitonmass

(torus compactif.)

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Coset space

Isometry group of GMN

Brane ground state

Branons (brane fluctuations)

Branons (x) GB fields Spontaneous isometry

breaking

Brane position

Sundrum, ‘99Dobado, A.L.M. ‘01

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• Bulk metric:

• Branon mass related to bulk curvature:

• Induced metric on the brane:

Branons

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Branon dynamics

Dirac-Nambu-GotoInduced metric

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KK gravitons vs. branons

KK-production Branon production

KK-SM coupling suppression

Bando et al. ‘99

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- Rigid branes ( f >> MD)

Kaluza-Klein modes Brane-world

scenario

- Flexible branes (f << MD)

Branon fields

(KK modes decouple from SM)

KK gravitons vs. branons

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• Phenomenology in colliders

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• Induced metric on the brane:

• Dirac - Nambu - Goto action:

Branon action

Limits from colliders

LEP-II ... TEVATRON-I

+ ...

hep-ex/0407017

Cembranos, Dobado, A.L.M, ’03

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Prospects for future colliders

Single photon-Z Monojet (quark production)

Monojet(gluon prod.)

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Prospects for future colliders

TEVATRON-II LHC

ILC

Cembranos, Dobado, A.L.M, ’04

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• Branons as dark matter

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• Brane orientation branons are pseudoscalar particles

• Parity on the brane branons couple by pairs to SM . (stable particles)

Branons are stable, massive and weakly interacting particles

NATURAL DARK MATTER CANDIDATES

A new dark matter candidate

Cembranos, Dobado, A.L.M, ’03

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+e1

-

ê1

+e1

e2

+

ê2

ê1

Parity on the brane

Odd-dimensional branes: pseudoscalar branons

Even-dimensional branes: scalar branons

P

P

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Branon cosmic abundance Freeze-out in an expanding universe:

Annihilation into all SM pairs X : ,

e.g. annihilation into photons, :

Cold branons (M >> T) Hot branons (M << T)

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Branon cosmic abundance

Cold branons

WMAP limits

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Branon cosmic abundance

Hot branons

WMAP WMAP-CBI-ACBAR-2dF-Ly-

BBN limits (light branons): for

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Combined limits

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Direct detection

Elastic branon-nucleon

cross section

(spin independent)

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Non-thermal branon production

(M f2 RB)1/2explicit symmetry breaking scale).

Branons are very light particles and decoupled from SM.

Brane initial position: Y0 = O (RB) and f 2 RB

Dark matter as coherent brane oscillations (similar to axions)

If H(T) > (T) for T < TRH brane oscillations only diluted by

Hubble expansion.

Non-thermal branon abundance:

A.L.M, ’04

If << TRH << Tf

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Non-thermal branon production

Tf < (M MP)1/2

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• Virtual branon effects

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Radiative corrections

Cembranos, Dobado, A.L.M, ’06

One-loop SM effective action

SM masses renormalization

New SM vertices

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Muon anomalous magnetic moment

Cembranos, Dobado, A.L.M, ’06

Brookaven (g-2) coll. (2004) 2.7above SM

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Conclusions and future perspectives

Low-energy branon dynamics universally described by effective action depending on 3 parameters (M,f,N) For f << MD only branons and SM particles relevant

degrees of freedom.

Limits on (M,f) from present and future colliders

Loop effects contribute to the muon anomalous magnetic moment

Branons are natural dark matter candidates (thermal or non- thermal production)

Future detection in direct or indirect experiments?