Cosmology/DM - IIKonstantin Matchev

Outline of the lectures• All lecture materials are on the web:

http://www.phys.ufl.edu/~matchev/PiTP2007 • Yesterday: became familiar with MicrOMEGAs. Forgot to

mention: – Bug in linking of libraries in case of new models– MicrOMEGAs can compute indirect detection yields– HW from Simulation Practicum at PiTP 2005 still applicable

• Earlier today: discussed several new physics models and their respective dark matter candidates– concentrate on WIMPs in SUSY and UED

• Now: discuss how collider and astro experiments can– discriminate between alternative models– determine DM properties

• Homework exercises throughout today’s lectures

Large Hadron Collider

ATLAS

CMSJura

CERN

Ebunch = 44 kJ

ECM = 14 TeV

How do we know LHC will find anything new or interesting?

• The X7 argument • Where is the Higgs?

Avenues for WIMP detection

• Potentially observable signals at colliders.

SM

SM

SM

SM

• Potentially observable signals of direct DM detection.

• Potentially observable signals of indirect DM detection.

SM

SM

SM

SM

Dark Matter at colliders: model-independent approach

• Relate the WIMP annihilation rate in the early Universe to the WIMP production rate at colliders. Detailed balancing:

• Predict the WIMP pair production rate

• Known parameters• Unknown parameters• Not an observable signature! What if ?

SM

SM

SM

SM

Birkedal,KM,Perelstein 2005

sSXtot ,, 0,,, JSMi

Detector Schematics

Note the absence of a “Missing energy calorimeter”

DM production at colliders

• In order to observe the missing energy, the DM particles must recoil against something visible

• If some sort of ISR (initial state radiation), model-independent prediction still possible,using soft/collinear factorization– Very challenging experimental signature,

does not seem to work

• Give up model-independence, look for production of the other, heavier states in the model – At LHC: typically the colored superpartners/KK partners– Problems:

• Proliferation of relevant model parameters• Complicated event topologies • Combinatorics confusion• Missing energy is challenging

Birkedal,KM,Perelstein 2005

SUSY Signature: MET + Jets + …

• Squark gluino production

• Full Geant4 Detector Simulation

• 6 hard jets• leptons• 2 LSPs + 4 ’s

MET Cleaning from Tevatron• MET is very powerful

SUSY discriminator• Difficult part is to convince

yourself that there is a real excess!

• Tevatron teaches us • MET is not easily

understood!

• Non-collisional backgrounds• Beam halo• Cosmic muons

• Detector Effects• Instrumental Noise• Hot/dead channels (DQM) D. Tsybychev, Fermilab-thesis-2004-58

Run IIV. Shary CALOR04

Run IIjunk

jets

e/

Jet/MET Reconstruction Performance

• Jets• Low luminosity Pileup included• ET Resolution

• Stochastic term 125% / √ET

• Constant term 3%• Angular Resolution

• High ET Jets: better than calo cell size( x = 0.087 x 0.087)

• Missing Transverse Energy• Low luminosity Pileup included• <MET> from QCD

• Stochastic term 123% / √ET

1700 GeV ET 700 GeV PT dijets 50 GeV observed MET

• MET Resolution• Low MET : approaches Jet size• High MET : approaches calo cell size

QCD

MET

Jets

CMS

CMS

Testing dark matter at colliders

• OK, so we see a missing energy signal at the LHC. What next? Is it due to dark matter?

• Look for confirmation from dark matter direct detection experiments. Colliders and astroparticle experiments test very different timescales. If signal seen in both, compare– Mass– Interaction strength

• Is it a thermal relic? Test the WIMP hypothesis:– Assume a model framework (discriminate look-alikes)– Measure the model parameters– Constrain the annihilation cross-section in the early Universe.

Supersymmetry or Extra Dimensions?m

ass

•Spins differ by 1/2 same as SM same as SM

•Higher levels no yes no

SUSY or UED? Part I

• Look for level 2 KK modes of UED

Datta,Kong,KM 2005 Datta,Kong,KM 2005

SUSY or UED? Part II

SUSY

q 02

~l

~

01

~UED

q near

l

farl1Q1Z

1l

1

• Can we measure the spins? Very difficult

• Recently, several proposed methods to measure spins and thus discriminate SUSY from UED

– Make assumptions what you know and can do– Propose a measurement– Interpret

Measuring spins at a lepton collider

• Find ~16 bln dollars, build a 3 TeV CLIC

• Study the processes shown in UED or SUSY

• Compare the angular distributions of the muons in the Lab

• Find out if UED or SUSY

Battaglia,Datta,DeRoeck,Kong,KM 2005

Barr Asymmetry

ll

llA

•Find the right jet among the 8-10 jets in the event (all of them look very similar)•Assume you know the masses of all new particles•Plot the asymmetry A+-

•Find out if UED or SUSY

Barr 2004

Pooh, is this Piglet flying like a kite, or is it a kite that looks like Piglet?

Pooh, is this SUSY that looks like UED, or is it

UED looking like SUSY?

PRECISION SUSY @ LHC

• Next, measure the model parameters• Only mass differences directly

measurable @ LHC: need to overconstrain the system

• Couplings are even more difficult• The “inverse problem” is tough!

Weiglein

et al. (2004)

HW

Contributions to NeutralinoWIMP Annihilation

Jungman, Kamionkowski, Griest (1995)

What do we know?

• Winning entry in the 2003 annual “Foot in mouth” award by the Plain English Campaign:

• “As we know, there are known knowns; there are things we

know we know.”

• “We also know there are known unknowns; that is to say we know there are some things we do not know.”

• “But there are also unknown unknowns - the ones we don't know we don't know.”

Testing the WIMP Hypothesis

• SUSY parameters– Relevant for DM– Irrelevant for DM

• … but also– Measured*– Unknown

• Consider all possible allowed variations of the “unknowns”

Birkedal,KM 2004

How well can one do?

• LHC/ILC determination of relic densities has now been studied by many groups.

Allanach, Belanger, Boudjema, Pukhov (2004)

Moroi, Shimizu, Yotsuyanagi (2005)

Baltz, Battaglia, Peskin, Wizansky (2006)

• Bottom line: LHC results are not always good, but ILC removes degeneracies Baltz, Battaglia, Peskin, Wizansky (2006)

IDENTIFYING DARK MATTERAre hep and cosmo identical?

Congratulations! You’ve

discovered the identity of dark

matter and extended our

understanding of the Universe to T = 10 GeV, t = 1 ns (Cf. BBN at T = 1 MeV, t = 1 s)

Yes

Yes

Yes

Calculate the new

hep

Can you discover another particle

that contributes to DM?

Which is bigger?

No

hepcosmo

Does it account for the rest of

DM?

YesNo

Did you make a

mistake?

Does itdecay?

Can you identify a source of entropy

production?

NoYes

No

No

Yes

Can this be resolved with some wacky cosmology?

Yes

No

No

Are you sure?

Yes

Think about the cosmological

constant problem

No

Courtesy of J.Feng, inspired by my T-shirt, IAS Princeton 2005

Discrepancies are interesting!

• Several DM species?• Kination domination

Chung,Everett,Kong,KM 2007

mohep cosmohep cos• SuperWIMPS

– gravitino, KK graviton• SuperWIMPS inherit the WIMP

miracle, but relic abundance is reduced by

Salati 2002

MeVT 1

Feng,Rajaraman,Takayama 2003

SM

NLSP

G ̃

WIMP

SuperWIMP

M

M

Avenues for WIMP detection

• Potentially observable signals at colliders.

SM

SM

SM

SM

• Potentially observable signals of direct DM detection.

• Potentially observable signals of indirect DM detection.

SM

SM

SM

SM

• Expected signal rates all over the place

• (Coherent) spin-independent scattering most promising for most WIMP candidates

• Theorists: q scatteringExperimentalists:

nucleus scatteringCompromise: p scattering

• MicrOMEGAs does not compute this, but DarkSUSY can.

Direct Detection

Indirect Detection

Dark Matter Madlibs!

Dark matter annihilates in ________________ to a place

__________ , which are detected by _____________ . particles an experiment

HESSCOLLIDERS ELIMINATE PARTICLE PHYSICS UNCERTAINTIES,

ALLOW ONE TO PROBE ASTROPHYSICAL DISTRIBUTIONS

ParticlePhysics

Astro-Physics

Very sensitive to halo profiles near the galactic center

Dark Matter annihilates in the galactic center to a place

photons , which are detected by GLAST, HESS, … . some particles an experiment

Dark Matter annihilates in the halo to a place

positrons , which are detected by AMS on the ISS . some particles an experiment

Ch

eng

,Fen

g,K

M 2002

Dark Matter annihilates in the center of the Sun to a place

neutrinos , which are detected by AMANDA, IceCube . some particles an experiment

(km -2 yr

-1) AM

AN

DA

in the Antarctic Ice

Fen

g,K

M,W

ilczek 2000

Final project

• Implement your (advisor’s) favorite dark matter model as CalcHEP model files

• Use MicrOMEGAs to calculate the relic density• Use MicrOMEGAs to estimate the indirect

detection rates• Use CalcHEP to estimate the size of the

collider signals at LHC/ILC