Significant effects of second KK Significant effects of second KK particles on LKP dark matter physicsparticles on LKP dark matter physics

Collaborated withCollaborated with

Mitsuru Kakizaki (ICRR)Mitsuru Kakizaki (ICRR)

Shigeki Matsumoto (ICRR)Shigeki Matsumoto (ICRR)

Yoshio Sato (Saitama U.)Yoshio Sato (Saitama U.)

hep-ph/0502059

Masato SenamiMasato Senami(ICRR, University of Tokyo)(ICRR, University of Tokyo)

senami@icrr.u-tokyo.ac.jpsenami@icrr.u-tokyo.ac.jp

Kaluza-Klein dark matterKaluza-Klein dark matter

WMAP result establish the existence of non-baryonic cold dark matter

Weakly Interacting Massive Particle (WIMP) is excellent candidate Lightest supersymmetric particle Lightest Kaluza-Klein particle (LKP)

in universal extra dimension (UED) models

…

http://lambda.gsfc.nasa.gov

Universal Extra Dimension modelUniversal Extra Dimension modelUniversal means all SM particles propagate in spatial extra dimensions

Momentum conservation in higher dim.= KK number conservation

KK parity conservation

To obtain chiral fermion at zero mode, the extra dimension is compactified by S1/Z2

LKP is stable

Mass spectrum

In 4 dim. viewpoint

LKP is a good candidate of DMLKP is a good candidate of DM

Eq. of motion

1/R=500 GeV, ΛR=20, mh=120 GeV

Mass of KK particleMass of KK particle Each KK mode has degenerate mass

Radiative corrections remove the degeneracy

Lightest KK particle

Mass spectrum

Cheng, Matchev and Schmaltz

(SM massless particles are exactly degenerate)

m = mass of LKP

Dark matter relic abundanceDark matter relic abundance After annihilation rate dropped

below the Hubble parameter, LKP can not annihilate and the density per comoving volume is fixed.

Large cross section

⇒ small relic abundance

Servant and Tait

Tree level annihilation diagrams

DM relic abundance

⇒Large mass of DM particle

They consider only the first KK modes

Second KK s-channelSecond KK s-channel

Since DM is non-relativistic,

the incident energy of two LKPs is almost degenerate with the mass of second KK modes

In particular, s-channel LKP annihilation process mediated by competes with tree level diagrams because of the resonance

does not couple withSM particle at tree level

One of the resonant diagrams We calculatethese type of diagrams

We find

Cross sectionCross section Parameters

For δ ～ 0.01, incident energy matches the pole and averaged cross section is significantly enhanced (10% ~ 100%)

δ ～ 0.01 is realized for

after the inclusion of the radiative corrections in the minimal UED

Dark matter abundanceDark matter abundance

The mass of the KK dark matter consistent with the WMAP data is around 950 GeV

This result is about 100 GeV above compared to the tree-level result

The resonant annihilation process mediated by causes this increase

Second KK resonanceSecond KK resonance The s-channel annihilation

First KK mass ~ m

Second KK mass ~ 2m Energy of two first KK mode

　　　 second KK mass second KK particle 　⇒　 s-channel

resonance`natural resonance’

This resonance is natural!

ConclusionConclusion

Second KK particle effect : `natural resonance’ Relic abundance of the LKP,

s-channel resonanceKK dark matter mass consistent with WMAP

~950 GeV (about 100 GeV above the tree result)

`Natural resonance’ affects coannihilation indirect detection collider signature

Second KK resonanceSecond KK resonance Coannihilation

If degenerate with in mass, coannihilates with

tree level coannihilation rate is small s-channel :

dipole type interaction

Indirect detection DM is almost at rest : good accuracy s-channel second KK B-boson

Collider signature Future linear e+e- collider s-channel second KK W-boson M. Battaglia et al. hep-ph/0502041

missing

Second KK Higgs mass differenceSecond KK Higgs mass difference

100 150 200 250 300

600

800

1000

1200

1400

1 % 0 %0.5 %

2 %1.5 %

-0.5 %

m

mh

(GeV)

(GeV)

Cross sectionsCross sections

Some diagramsSome diagrams

Radiative correctionsRadiative corrections

　Weak mixing anglesTree level mass spectrum

AbstractAbstract

SUSY UED similarity

LHC で new physics を発見しても区別できない

superparticle, soft mass

stable LSPfirst KK mode, 1/R mass

stable LKP

superpartner : single different spin

KK mode : tower identical spin

angular distributionenergy spectrumtotal cross-section

Lepton collider! Compact Linear Collider (CLIC)

1/R=500 GeV, ΛR=20, mh=120 GeV

Radiative correctionsRadiative corrections Radiative corrections remove the

degeneracyLightest KK particle

Second KK particles couple to SM particles(KK number violating interaction

is forbidden by the momentum conservation)

n=20

0

11

1

Comparison of UED and SUSYComparison of UED and SUSY

UED parameter is chosen naturally

MSSM parameter is adjusted to UED parameter

Back ground

Events

～ 20fb

small polar angle

missing energy > 2.5 TeVtransverse energy < 150 GeVevent sphericity 　 > 0.05

Angular distribution and spin measurementsAngular distribution and spin measurements

UED

SUSY

UED SUSY

14.4 fb

2.76 fb

Background free!!

Threshold scansThreshold scans

cross section

includebeamstrahlung

confirm に利用New particle の質量決定

Muon energy spectrumMuon energy spectrum

UED SUSY

UED

SUSY

For UED,

UED,SUSY の区別には使えない

ResonanceResonance SUSY Z,γ 　 s-channel UED Z2,γ2 s-channel Resonance!!

is kinematically forbidden.

is kinematically allowed.

is mostly -likeand predominantly couple to

1/R = 1350 GeVWeak mixing angle for second KK mode is very small