LHC / ILC / Cosmology Interplay Sabine Kraml (CERN) WHEPP-9, Bhubaneswar, India 3-14 Jan 2006

LHC / ILC / Cosmology Interplay

Sabine Kraml (CERN)

WHEPP-9, Bhubaneswar, India

3-14 Jan 2006

WHEPP-9 Bhubaneswar 2S. Kraml

Outline

Introduction Relic density of WIMPs SUSY case as illustrative example

Neutralino dark matter Requirements for collider tests Implications of CP violation

Conclusions


What is the Universe made of? Cosmological data:

4% ±0.4% baryonic matter 23% ±4% dark matter 73% ±4% dark energy

Particle physics: SM is incomplete; expect

new physics at TeV scale NP should provide the DM Discovery at LHC, precision

measurements at ILC ?


Dark matter candidates

Neutralino, gravitino, axion, axino, lightest KK particle, T-odd little Higgs, branons, Q-balls, etc., etc...

New Physics


WIMPs (weakly interacting massive particles)

DM must be stable, electrically neutral,

weakly and gravitationally interacting

WIMPs are predicted by most BSM theories Stable as result of discrete symmetries Produced as thermal relic of the Big Bang Testable at colliders! Neutralino, gravitino,

axion, axino, LKP, T-odd Little Higgs, branons, Q-balls, etc., ...


Relic density of WIMPs(1) Early Universe dense and hot;

WIMPs in thermal equilibrium

(2) Universe expands and cools; WIMP density is reduced through pair annihilation; Boltzmann suppression: n~e-m/T

(3) Temperature and density too low for WIMP annihilation to keep up with expansion rate → freeze out

Final dark matter density: h2 ~ 1/<v>Thermally avaraged cross section of all annihilation channels

WMAP: 0.094 < h2 < 0.129 @ 2


Collider tests of WIMPs

Generic WIMP signature at LHC: jets (+leptons) + ET

miss

Great for discovery; resolving the nature of the WIMP however not obvious

Need precision measurements of masses, couplings, quantum numbers, .... → ILC

WMAP

LHC

ILC


Neutralino-LSP in the MSSM


Minimal supersymmetric model SUSY = Symmetry between fermions and bosons

If R-parity is conserved the lightest SUSY particle (LSP) is stable → LSP as cold dark matter candidate

SM particles spin Superpartners spin

quarks 1/2 squarks 0

leptons 1/2 sleptons 0

gauge bosons 1 gauginos 1/2

Higgs bosons 0 higgsinos 1/2

mix to

2 charginos +

4 neutralinos


Neutralino system

Neutralino mass eigenstates

Gauginos

Higgsinos

→ LSP


Neutralino relic densitySpecific mechanisms to get relic density in agreement with WMAP

0.094 < h2 < 0.129 puts strong bounds on the parameter space


mSUGRA parameter space

GUT-scale boundary conditions: m0, m1/2, A0

[plus tan, sgn()]

4 regions with right h2 bulk (excl. by mh from LEP)

co-annihilation Higgs funnel (tan ~ 50) focus point (higgsino scenario)


Prediction of <v> from colliders:What do we need to measure?

LSP mass and decompositionbino, wino, higgsino admixture

Sfermion masses (bulk, coannhilation)or at least lower limits on them

Higgs masses and widths: h,H,A tan

With which precision?


What do we need to measure with which precision:

Coannihilation with staus, M<10 GeV

M(stau-LSP) to 1 GeV Precise sparticle mixings Difficult at LHC; soft tau´s! Achievable at ILC:

Stau mass at thresholdBambade et al, hep-ph/040601

Stau and Slepton massesMartyn, hep-ph/0408226

Stau-neutralino mass difference Khotilovitch et al,

hep-ph/0503165

Beam polarization essential! [Allanach et al, hep-ph/0410091]

~


Golden decay chain at LHC

Stau coannihilation region: leptons will mostly be taus

Small stau-LSP mass difference M ≤ 10 GeV leads to soft ´s

Difficult to measure mkinematic endpoint for mass determination


Determination of slepton and LSP massesat the ILC

[Martyn, hep-ph/0408226]


Determination of the neutralino systemLHC+ILC case study for SPS1a: light -inos at ILC; neutralino4 at LHC

[Desch et al., hep-ph/0312069]



Higgsino LSP, ~ M1,2

Annihilation into WW and ZZ via t-channel ± or

Rate determined by higgsino fraction fH=N13

2+N142

1% precision on M1 and

All neutralinos/charginos; mixing via pol. e+e- Xsections

LHC: discovery via 3-body gluino decays / Drell-Yang

[Allanach et al, hep-ph/0410091]

Fractional accuracies needed


[J.L. Feng et al., ALCPG]

Scan of focus point scenario, LCC2m0 = 3280 GeV, m1/2 = 300 GeV, A0 = 0, tanb = 10



Annihilation through Higgs

Mainly → A → bb CP even H exchange is

P-wave suppressed mandmAto 2%-2‰

(mA-2m) and to 5% A width to 10%

g(A)~N132-N14

2, g(Abb)~hb, ....

Fractional accuracies needed

[Allanach et al, hep-ph/0410091]


Influence of mA on evaluation of h2

→ large uncertainty if lower limit on mA is not >> 2 mLSP

[Birkedal et al, hep-ph/0507214]


e+ e_

→ H A

[Heinemeyer et al., hep-ph/0511332]

A not produced in Higgs-Strahlung, need e+e_ → HA

H,A masses to ~1 GeV; limitation by kinematics! Widths only to 20%-30% Production in mode can help a lot


Heavy Higgses at LHCH/A in cascade decays


For a precise prediction of h2

compatible with WMAP acurracy we need precision measurements

of most of the SUSY spectrum

→ LHC/ILC synergy


So far considered CP conserving MSSM

What if CP is violated?[we actually need new sources of CP violation

beyond the SM for baryogenesis]


CP violation In the general MSSM, gaugino and higgsino mass

parameters and trilinear couplings can be complex:

Important influence on sparticle production and decay rates → Expect similar influence on <v>

NB1: M2 can also be complex, but its phase can be rotated away.

NB2: CPV phases are strongly constrained by dipole moments;

we set =0 and assume very heavy 1st+2nd generation sfermions


CP violation: Higgs sector Non-zero phases induce CP violation in the Higgs sector

through loops → mixing of h,H,A:

Couplings to neutralinos:


Previous studies of neutralino relic density with CP violation


CPV analysis with micrOMEGAsM1 = 150, M2 = 300, At = 1200 GeV, tan = 5

masses of 3rd gen: 500 GeV, 1st+2nd gen: 10 TeV

bino-like LSP, m ~ 150 GeV h2 < 0.129 needs annihilation through Higgs

Scenario 1: = 500 GeV → small mixing in Higgs sector Scenario 2: = 1 TeV → large mixing in Higgs sector

Higgs mixing ~ Im(At)

[Belanger, Boudjema, SK, Pukhov, Semenov, in: LesHouches‘05]


CPV with micrOMEGAs


Scenario 2

Key parameter is distance from pole


Recall Higgs funnels in mSUGRA

mA=


Higgs funnel with large Higgs CP-mixing

Green bands: 0.094 < h2 < 0.129

dmi = mhi - 2mLSP, i=2,3

h3 h3

h3

h2



Green bands: 0.094 < h2 < 0.129

h3 h3

h3

h2



Green bands: 0.094 < h2 < 0.129

dmi = mhi - 2mLSP, i=2,3

h3


CP violation is a very interesting option can have order-of-magnitude effect on h2

needs to be tested precisely

However: computation of annihilation cross sections at only at tree level; radiative corrections may be sizeable!


Assume we have found SUSY with

a neutralino LSP and made very precise

measurements of all relevant parameters:

What if the inferred

h2 is too high?


Solution 1:

Dark matter is superWIMP

e.g. gravitino or axino


Solution 2:

R-parity is violated after all

RPV on long time scales

Late decays of neutralino LSP reduce the number density; actual CDM is something else

Very hard to test at colliders

Astrophysics constraints?


Our picture of dark matter as a thermal relic

from the big bang may be to simple The early Universe may have evolved differently .... .... ....

Solution 3:

Cosmological assumptions are wrong


Conclusions: We expect new physics beyond the SM

to show up at the TeV energy scale to provide the dark matter of the Universe

Using the example of neutralino dark matter I have shown that precison measurements at both LHC+ILC are necessary to pin down the nature and properties of the dark matter

h2 ~ 1/<v> from LHC/ILC ↔ WMAP acurracy Direct detection in addition to pin down DM


WMAP

LHC

ILC

Accuracies of determining the LSP mass and its relic density[Alexander et al., hep-ph/0507214]


What if only part of the spectrum is accessible?

Part of the spectrum may escape detection Too heavy sparticles, only limits on masses Not enough sensitivity, e.g. H,A Only LHC data available, ....

Model assumptions, fits of specific models, etc,

to obtain testable predicions [or to test models]

Famous example: Fit of mSUGRA to LHC data at SPS1a

Need precise predictions within models of SUSY breaking


Comparison of SUSY spectrum codes

Computation of SUSY spectrum with 4 state-of-the-art SUSY codes: Isjet, Softsusy, Spheno, Suspect

2loop RGEs + 1loop threshold corrections, 1loop corr. to Yukawa couplings, ...

Computation of relic desity with micrOMEGAs Mapped mSUGRA parameter space for

differences in predictions of h2

differences in WMAP exclusions

due to spectrum uncertainties

[Belanger, SK, Pukhov, hep-ph/0502079]



Stau-LSP mass difference!M) ~ 1 GeV → ~ 10%

Uncertainties from sparticle mass predictions O(1%)moderate parameters, stau coannihilation

Contours of h2=0.129



Uncertainties from sparticle mass predictions: large tan and the Higgs funnel


There is need to improve computations and tools in order to match acurracies required by WMAP/Planck

Improvements in spectrum computations are discussed in [Baer, Ferrandis, SK, Porod, hep-ph/0511123]

Documents

LHC / ILC / Cosmology Interplay Sabine Kraml (CERN) WHEPP-9, Bhubaneswar, India 3-14 Jan 2006