Cosmology/DM - II Konstantin Matchev

Outline of the lectures All lecture materials are on the web: 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 CMS Jura CERN E bunch = 44 kJ E CM = 14 TeV

How do we know LHC will find anything new or interesting? The X 7 argumentWhere is the Higgs?

Avenues for WIMP detection Potentially observable signals at colliders. SM     Potentially observable signals of direct DM detection. Potentially observable signals of indirect DM detection. 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     Birkedal,KM,Perelstein 2005

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 Run II V. Shary CALOR04 Run II junk jets e/ 

Jet/MET Reconstruction Performance Jets Low luminosity Pileup included E T Resolution Stochastic term  125% / √E T Constant term  3% Angular Resolution High E T Jets: better than calo cell size (  x  = x 0.087) Missing Transverse Energy Low luminosity Pileup included from QCD Stochastic term  123% / √  E T  1700 GeV  E T   700 GeV P T dijets   50 GeV observed MET MET  Resolution Low MET : approaches Jet size High MET : approaches calo cell size QCD MET Jets 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? mass Spinsdiffer by 1/2same as SM Higher levelsnoyesno

SUSY or UED? Part I Look for level 2 KK modes of UED Datta,Kong,KM 2005

SUSY or UED? Part II SUSY q 0 2 ~   l ~ 0 1 ~  UED q  near  l  far  l 1 Q 1 Z  1 l 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 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 LHC Next, measure the model parameters Only mass differences directly LHC: need to overconstrain the system Couplings are even more difficult The “inverse problem” is tough! Weiglein et al. (2004) HW

Contributions to Neutralino WIMP 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 MATTER Are  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 Calculate the new  hep Can you discover another particle that contributes to DM? Which is bigger? No  hep  cosmo Does it account for the rest of DM? Yes No Did you make a mistake? Does it decay? Can you identify a source of entropy production? No Yes No Yes Can this be resolved with some wacky cosmology? Yes 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 SuperWIMPS –gravitino, KK graviton SuperWIMPS inherit the WIMP miracle, but relic abundance is reduced by Salati 2002 Feng,Rajaraman,Takayama 2003 SM NLSP G̃G̃

Avenues for WIMP detection Potentially observable signals at colliders. SM     Potentially observable signals of direct DM detection. Potentially observable signals of indirect DM detection. SM    

Expected signal rates all over the place (Coherent) spin-independent scattering most promising for most WIMP candidates Theorists:  q scattering Experimentalists:  nucleus scattering Compromise:  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

HESS COLLIDERS ELIMINATE PARTICLE PHYSICS UNCERTAINTIES, ALLOW ONE TO PROBE ASTROPHYSICAL DISTRIBUTIONS Particle Physics 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 Cheng,Feng,KM 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 ) AMANDA in the Antarctic Ice Feng,KM,Wilczek 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