Transcript Document
To start…
LHC-DM@NA
Luigi Cappiello & Gianpiero Mangano 20 novembre 2008
Direct measurements (nuclear recoils) Cosmology, Relic abundance
DM Candidate
LEP, Tevatron, precision meaurements Gamma experiments v fluxes LHC Antimatter 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 R 3 + 1 spacetime dimensions 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 A 5 ??
Fermion fields interact chirally, e.g. lepton SU(2) doublet L L In 5 dimensions no chirality. Orbifolding: R S 0 S/Z 2
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: E 2 = p 2 + m 2 + n 2 /R 2 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 anomalous heavy matter-KK isotopes from observations (non 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 y 4 3
m B 2 1
S-wave!
Relic abundance, scattering off nuclei (direct searches) and annihilation in the local halo (indirect searches) intertwined Bino: p-wave into fermions
B~ f f ~ B~ f
Computing the relic abundance
x fr h 2
4
3 Gg ( 45 : n eq ( x fr )
v m )
1 / 2
H ( 30 x fr x fr T 0 3 )
v
cr
0 .
3
x fr 10
g ( m 100 )
1 / 2 10
39
v cm 2
g y 4 3
m B 2 1
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 =(m q1 -m B1 )/m B1 3 -sigma detection (atmospheric neutrino background)
LEP, Tevatron, precision meaurements
LEP EW Precision Observables 1-UED new physics contribution to gauge boson vacuum polarization Summary of constraints From rare decays and flavor physics 95 95%CL 99 99%CL 2) 1) SM
Lower and upper bonds on R -1
Interesting effects also on rare decays, e.g.
1) Loop effects K-top, KK-W, K-scalar 2) Loop effects K-top, KK-H
UED
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
Largest overall rate through q 1 pairs
Production cross-section of KK-pairs
( small) E miss + (N
2) Jets (soft) 1/R < 1.2 TeV Gold plate channel
Tot. Integr. Luminosity vs 1/R
E miss + 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 points (0, : estimates are somewhat model-dependent on assumpption on the relevance of counterterms in the UED lagrangian coming from the boundary p R) 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 s 1/2 =1TeV and 250GeV
Cross-section and forward-backward Asymmetry vs 1/R for N=1 KK N=2 single KK mode production
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 (*) in the Galactic halo KK
e -
KK
e +
anomaly excess of e + /(e + +e ) at high E Kin >7-10GeV anti-deuteron anti-proton positron Flux Vs Kin.Energy
The longer the path toward the observed e + spectrum ...
KK
hard e + Galaxy
KK
soft e + Diffusion (Inv. Compton, sync. rad. ] S-wave enhancement due to Sommerfeld effect Solar modulation
... the harder is the work to calculate it.
Use PYTHIA Halo model of DM distribution Diffusion model
modeled on Cosmic Rays
Use e + /(e + +e )
Boost factors
or
Sommerfeld effect (DM clumps ?
Spatial inhomogeneities)
To be continued ... PAMELA et al.