gravitons and dark matter in universal extra dimensionsconferences.fnal.gov/dmwksp/talks/graviton...

Gravitons and Dark Matter in Universal Extra Dimensions

Nausheen R. ShahCarlos E. M. WagnerPRD 74:104008, 2006 [arXiv: hep-ph/0608140]

Enrico Fermi Institute and Kavli Institute for Cosmological Physics, University of Chicago.

HEP Division, Argonne National Labs.

Universal Extra Dimensions

Models beyond Standard Model (SM) frequently y ( ) q yimply existence of extra dimensions (ED).

Simplest incorporation of ED: Universal Extra Simplest incorporation of ED: Universal Extra Dimensions.

All fi ld t i EDAll fields propagate in ED.

Only one free parameter: mKK~1/R. Only one free parameter: mKK 1/R.

Nausheen R. Shah Fermilab May 2007

Universal Extra Dimensions

D = 5:D 5:S1/Z2 (-1)KK KK Parity

LKP Stable

LKP DM Candidate w/ mKK ~ O(1) TeVKK ( )


Gravitons?

G1 as the LKP very tightly constrained by G as the LKP very tightly constrained by Big Bang Nucleosynthesis (BBN) and diffuse gamma spectrum. diffuse gamma spectrum. Usually effect of the G1 when it is not the LKP considered not important, since all LKP considered not important, since all interactions are Planck suppressed. We will show that in fact the gravitons We will show that in fact the gravitons can have significant effects on the DM density.


y

Reheating Temperature

LKP Freeze OutNonthermal

Graviton Production

Thermal Productionof LKP

BBN

LKP Freeze Out Graviton ProductionVia collisions

BBN and Diffuse Gamma

Gravitons decay to the LKP

BBN and Diffuse GammaRay Constraints on

Graviton Decay. ΩGn ~ C [TR / mKK]7/2

Present Day ΩDM = ΩLKP + ΩG

Gn [ R KK]


Present Day ΩDM ΩLKP + ΩGn

Reheating Temperature

Demanding that ΩDM = ΩLKP + ΩGn be Demanding that ΩDM ΩLKP + ΩGn be consistent with observation, shows us that we can lower the LKP mass as much as we wish as long as the reheating temperature behaves accordingly:


Values of the reheating temperature obtained by demanding a proper DM density, for different values of the graviton production

t C f D 5 Al h li f t t ti f th parameter C for D=5. Also shown are lines of constant ratios of the reheating temperature to the lightest KK mass.

210210210

)

210

)

210

)

210 C = 0.01

C = 0.1

KK = 100mRT

KK = 70mRT

(TeV

)RT (T

eV)

RT (T

eV)

RT

C = 1

C = 0.1

KK = 40m

RT

T

10

T

10

T

10

(TeV)m0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

(TeV)m0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

(TeV)m0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9


(TeV)KKm (TeV)KKm (TeV)KKm

Additional Contributions to the Annihilation Cross-Section

A precise calculation for LKP density must include co-p yannihilation and second KK resonances effects. This changes the numerical results obtained, but the qualitative picture presented remains unchanged. These corrections can be quantified by noting that due to the weak logarithmic dependence of xF, we can approximately parameterize Y as being proportional to mKK:pp y p g p p KK

The change in mWG necessary to reproduce the correct DM density for a given T is given by:density for a given TR is given by:


Values of the ratio of the LKP mass consistent with DM density to the one obtained in the absence of gravitons, mWG, for TR = 20 mKK and D 5D=5

111C = 0.1

C = 0.01

W

G 0.9

0.95

W

G 0.9

0.95

W

G 0.9

0.95

C = 0.1

C = 1

WG

/mK

Km

0.85

0.9WG

/mK

Km

0.85

0.9WG

/mK

Km

0.85

0.9

0.75

0.8

0.75

0.8

0.75

0.8 KK = 20mRT

(TeV)WGm0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4

0.7

0.75

(TeV)WGm0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4

0.7

0.75

(TeV)WGm0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4

0.7

0.75


(TeV)WGm (TeV)WGm (TeV)WGm

TR = 40 mKK, D = 5.

1

1.1

1

1.1

1

1.1

C = 0.01

W

G

0.7

0.8

0.9

W

G

0.7

0.8

0.9

W

G

0.7

0.8

0.9

C = 1

C = 0.1

W/m

KK

m

0.5

0.6

0.7W/m

KK

m

0.5

0.6

0.7W/m

KK

m

0.5

0.6

0.7

0.3

0.4

0.5

0.3

0.4

0.5

0.3

0.4

0.5

KK = 40mRT

(TeV)WGm0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4

0.2

0.3

(TeV)WGm0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4

0.2

0.3

(TeV)WGm0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4

0.2

0.3



TR = 100 mKK, D=5.

0.8

0.9

1

0.8

0.9

1

0.8

0.9

1

KK = 100mRT

W

G 0.6

0.7

0.8

W

G 0.6

0.7

0.8

W

G 0.6

0.7

0.8

C = 0.01

W/m

KK

m 0.4

0.5

0.6W/m

KK

m 0.4

0.5

0.6W/m

KK

m 0.4

0.5

0.6

C = 0.1

0.1

0.2

0.3

0.1

0.2

0.3

0.1

0.2

0.3C = 1

(TeV)WGm0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4

0.1

(TeV)WGm0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4

0.1

(TeV)WGm0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4

0.1



Decay LifetimesWe found that Gn , for n>1, primarily decays to a pair of gauge bosons with equal KK numbers, with lifetime given by:

Only long lived graviton is G1 with a lifetime given by:Only long lived graviton is G1, with a lifetime given by:


Constraints on the G1-B1 mass difference.

If we assume that the reheating temperature If we assume that the reheating temperature is such that Ω = 0.23, we find that to preserve BBN predicted light element abundances :

Additionally requiring that late decays don’t destroy the diffuse photon flux:


Combined constraints due to both BBN and observed diffuse flux on the mass difference.

Excluded to preserve BBN predictedlight element abundances.

V) -310V) -310V) -310

C=0.01

C=0.1

light element abundances.

(TeV

)1Δ

-310

(TeV

)1Δ

-310

(TeV

)1Δ

-310 C=0.1

C=1

Excluded to preserve observed

Diffuse Photon Flux

(TeV)KKm0.3 0.4 0.5 0.6 0.7 0.8 0.9

(TeV)KKm0.3 0.4 0.5 0.6 0.7 0.8 0.9

(TeV)KKm0.3 0.4 0.5 0.6 0.7 0.8 0.9

Diffuse Photon Flux



One Loop Corrections to the KK Masses.

The gauge boson mass matrix due to the The gauge boson mass matrix due to the Higgs vev in the B n, W 3n basis:

Since the mixing is very small, the B1 is very well approximated by:well approximated by:


Absolute value of the one loop corrections to the B1 mass in the MUED as a function of mKK. The graviton would be the LKP below

800 G V masses ~ 800 GeV. -210-210-210

eV)

eV)

eV)

| (Te

V1-

Loop

|

-310| (Te

V1-

Loop

|

-310| (Te

V1-

Loop

|

-310

1δ|

-410

1δ|

-410

1δ|

-410

(TeV)m0.5 1 1.5 2

-410

(TeV)m0.5 1 1.5 2

-410

(TeV)m0.5 1 1.5 2

-410



Determining the Reheating Temperature

Due to small couplings to matter, provided the p g , pG1 is not the LKP, it will not be produced in laboratory experiments.

If conclusive evidence for UED is found in collider experiments, and relevant properties of p , p pthe first and second modes were measured, then assuming that no other exotic particle exists we could estimate the contribution of the exists, we could estimate the contribution of the Gn to the relic density, and therefore be able to infer the reheating temperature.


If LKP observed at LHC, the reheating temperature required to make up the deficit DM density by KK gravitons.

30

35

30

35

30

35

C=1

eV)

25

30

eV)

25

30

eV)

25

30

(TeV

RT

15

20

(TeV

RT

15

20

(TeV

RT

15

20

10

15

10

15

=0.05ΩΔ

=0.1ΩΔ

=0.15ΩΔ

10

15

(TeV)KKm0.2 0.4 0.6 0.8 1 1.2

5

(TeV)KKm0.2 0.4 0.6 0.8 1 1.2

5=0.15ΩΔ

(TeV)KKm0.2 0.4 0.6 0.8 1 1.2

5



Conclusion

We have studied the cosmological effects of the inclusion of the graviton tower in detail graviton tower in detail.

Conventionally, due to Planck suppression, the graviton has been ignored. We have shown that it can in fact have significant

ff teffects.

Requiring that the graviton decays don’t destroy BBN predicted light element abundances and the diffuse gamma ray flux, we g g y ,have obtained a bound on the mass difference between the G1

and the LKP, which is consistent with the one obtained from one loop corrections in the MUED for a large range of values of mKK.

If UED is observed experimentally, we show that an upper limit on the reheating temperature can be deduced.


gravitons and dark matter in universal extra dimensionsconferences.fnal.gov/dmwksp/talks/graviton...

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