Document

Report
To start…
[email protected]
Luigi Cappiello & Gianpiero Mangano
20 novembre 2008
Direct measurements
(nuclear recoils)
LEP, Tevatron,
precision
meaurements
Cosmology,
Relic abundance
DM Candidate
LHC
Antimatter
fluxes
Gamma experiments
v fluxes
The Candidate:
Kaluza Klein
Dark Matter
Theories with compactified extra dimensions allows for infinite
towers of heavy states corresponding to all SM degrees of freedom
(Universal Extra Dimensions UED)
KK DM
Boson, s-wave annihilation
SUSY DM (e.g. Neutralino)
Majorana fermion, p-wave annihilation
X
3 + 1 spacetime
dimensions
R
D extra dimensions
compactified as circles, torii
etc.
Problems: extra massless states, chiral structure of the Standard
Model
Solution: Orbifolding, KK parity
Standard Model Lagrangian
Plane wave decomposition
Consider photon field (4+1 dimensions):
A massless
A5 ??
Fermion fields interact chirally, e.g. lepton SU(2)
doublet LL
In 5 dimensions no chirality.
Orbifolding:
R
S
S/Z2
0
Fields can be assigned a parity under
orbifold transformation (odd, even)
Boson fields
Fermion (chiral) fields
KK excitations of (chiral) fermions are vector-like under SM group
KK parity is conserved in interactions (unless explicitly
broken)
In 5 dimensions: KKP = (-1)n
i) KK odd excitations only produced in pairs
ii) Lighest KK (n=1) state is stable. Candidate for DM
Particle Spectrum
Tree level:
E2 = p2 + m2 + n2/R2
Radiative corrections due to breaking of 5-d Lorentz invariance
Best DM candidate: photon – like KK
UED pro’s and con’s
con’s
1. it does not solve the hierarchy problem
2. do not include gravity
3. Stabilization of extra dimensions ?
pro’s
1. UED DM candidate is a necessary outcome of the model
2. DM constraint and indirect limits on compactification
radius guarantee a spectrum which is within the reach of
LHC
3. First excited states of the SM particles should be between
400 – 900 GeV
Cosmology: the relic abundance
Relic particles should be uncharged under SU(3)c or U(1)Q (non
anomalous heavy matter-KK isotopes from observations
KK excitations of Z and neutral Higgs typically heavier
KK neutrinos have too large scattering cross sections on nuclei (CDMS)
B (photon) natural KKDM candidate
Relic density fixed by annihilation cross section
g
 
2
3 mB 1
4
y
S-wave!
Relic abundance,
scattering off nuclei
(direct searches) and
annihilation in the
local halo (indirect
searches) intertwined
Bino: p-wave into ~
B
fermions
f
~
B
~
f
f
Computing the relic abundance
1/ 2
3
x
T


4

Gg
(
m
)
 xfr
2
fr 0
h 
 0.3 

45
30 v cr
 10


xfr : n eq ( xfr ) v  H ( xfr )
3
gy4
 
3 mB21
1/2
 g ( m ) 


 100 
10 39 cm2
v
Direct measurements (nuclear recoils)
DM-nucleus elastic scattering
Many running and planned experiments:
CDMS, Edelweiss, Zeplin, CRESST, CLEAN, COUPP, DEAP, DRIFT, EURECA, SIGN,
XENON, WARP, KIAS, NaIAD, Picasso, Majorana, DUSEL, IGEX, ROSEBUD,
ANAIS, KIMS, Genius, DAMA, LIBRA
Spin independent:
+ quark – KK quark loops
Spin dependent large but under future
experiment sensitivity
Gamma experiments
Gammas (and energetic neutrinos and antimatter) can be
produced from LKP by annihilations in high density
structures (center of galaxy, clumps,…)
Productions of continuum via final state radiation and line
emissions via loop processes
DM in halos typically mass independent and
universal (N-body simulation), as e.g. NFW,
but results do not include baryonic matter
Background: astrophysical sources emit up to (and above) 10 TeV
HESS, MAGIC
Main channels are lepton and quark pairs which decay and
fragment (neutralino is quite different…)
Smoking guns: gamma lines from , Z, H processes
Perspectives: GLAST covers sub-GeV up to 300 GeV region
For a NFW up to 3-4 events per year above few GeV expected
from the galactic center, but galactic background is high
Mini halo, clump rate difficult to assess
v fluxes
v fluxes produced in the halo difficult to observe.
Larger effect if KKDM gets captured in the sun and then
annihilates
Capture rate and annihilation rate leads to stationary
conditions for
Neutrinos produced directly via charged leptons (tau) and
pions
Energetic neutrinos produced more than in neutralino
scenario
IceCube or Km3Net
Present bounds from SK,
Amanda, Baksan
=(mq1-mB1)/mB1
3 -sigma detection
(atmospheric neutrino
background)
LEP, Tevatron, precision meaurements
LEP EW Precision Observables
1-UED
new physics contribution to gauge boson
vacuum polarization
95
Summary of constraints From rare
decays and flavor physics
95%CL
99
99%CL
1)
2)
Lower and upper bonds on R-1
SM
1) Loop effects K-top, KK-W, K-scalar
2) Loop effects K-top, KK-H
UED
Interesting effects also on
rare decays, e.g.
Accelerator Searches: Tevatron
Mass spectrum of n=1 level (after rad. Corr.)
Decays ( KK-parity conserved )
Process
CDF
L=87.5 pb -1
(KKqq) =3,3pb(2.5pb) 95%CL(90%CL)
1/R>270 (280) GeV
(KKqq, KK-qg, KK-gg ) =7,9pb(6.0pb) 95%CL(90%CL)
1/R>280 GeV
Future Colliders and UED
LHC: Discovery machine but Problems with signature
Production cross-section of KK-pairs
Largest overall rate through q1 pairs
(small) Emiss + (N

2) Jets (soft)
1/R < 1.2 TeV
Gold plate channel
Tot. Integr. Luminosity vs 1/R
Emiss + 4 leptons
UED discovery reach in the golden plate channel.
5-s excess of 5 signal events L vs 1/R
Other channels affected by larger backgrounds
Warning: estimates are somewhat model-dependent
on assumpption on the relevance of counterterms
in the UED lagrangian coming from the boundary
points (0, pR) Could change the mass spectrum
ILC: Accurate measurements of UED particle properties
and discrimination of UED from other scenarios i.e. SUSY
N=1 pair production
Resonant production of B2 and Z2 for s1/2=1TeV and 250GeV<R-1<450 GeV
Cross-section and forward-backward
Asymmetry vs 1/R for
N=2 single KK mode production
N=1 KK
Resonant production of B2 and Z2
N=2 KK
N=1 KK
95% CL exclusion limits
from combined leptonic
and hadronic final states
at ILC
Antimatter searches ( before PAMELA data )
Generically, WIMP annihilations (*) yeld as much matter and antimatter in cosmic rays
KK
anomaly
KK
(*) in the Galactic halo
e-
e+
excess of e+/(e++e-)
at high EKin >7-10GeV
anti-deuteron
anti-proton
positron
Flux
Vs
Kin.Energy
The longer the path toward the observed e+ spectrum ...
Galaxy
hard e+
KK
soft e+ Diffusion
KK
(Inv. Compton,
sync. rad. ]
S-wave enhancement due to Sommerfeld effect
(DM clumps ?
Spatial
inhomogeneities)
Solar modulation
... the harder is the work to calculate it.
Use PYTHIA
Halo model of
DM distribution  (r)
Diffusion model
modeled on
Cosmic Rays
Use e+/(e++e-)
Boost factors
or Sommerfeld effect
To be continued ... PAMELA et al.

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