Contributions by M. Peskin, E. Baltz, B. Sadoulet, T. Wizansky

Transcription

1 Contributions by M. Peskin, E. Baltz, B. Sadoulet, T. Wizansky

2 Dark Matter established as major component of the Universe: CMB determination of its relic density further confirmed by SNs and galaxy clusters; Additional astrophysical data manifest possible evidence of DM annihilation: EGRET data show excess of γ emission in Inner Galaxy; WMAP data may show excess of synchrotron emission; Picture of structure formation in weakly interacting matter may explain structure in Universe from scale of CMB fluctuations to that of Galaxies; < Ω CDM h 2 < Finkbeiner, astro-ph/

3 Cosmology tells us that a significant fraction of the Universe mass consists of Dark Matter, but does not provide clues on its nature; Particle physics tells us that New Physics must exists at, or just beyond, the EW scale and new symmetries may result in new, stable particles; As the generation of collider experiments will access TeV scale, we have the opportunity to directly produce and precisely study microscopic properties of dark matter candidate particle and to compare these data to what we are learning from satellite and direct detection experiments. From WMAP determination of DM density and infer that DM particle mass should be Ο(100 GeV)

4 Several models of New Physics beyond the Standard Model offer viable candidates for weakly-interacting, neutral, heavy DM particle; Supersymmetry with conserved R-parity: Lightest supersymmetric particle (LSP) stable can be DM candidate; Main candidate is lightest neutralino χ 0 1 whose relic density depends on mass and interaction with other particles (annihilation cross section) Universal Extra dimensions with conserved KK-parity Warped Extra dimensions with conserved Z 1 parity

5 WIMP Dark Matter in cmssm SUSY models analysis simplified within cmssm: dimensionality of parameter space reduced by one (m 1/2 ): four regions emerge: m 0 Cosmologically interesting regions in cmssm parameter space: Bulk Region Co-Annihilation Region A 0 Funnel Region Focus Point Region m 0 No EWSB LCC2 m h, b sγ g 2 Focus Point Region LCC4 Funnel Region LCC3 Bulk Region Charged LSP LCC1 co Annihilation Region m 1/2 Constrained MSSM useful template to define benchmarks, signatures; assessment of physics reach must be performed on full MSSM.

6 Accelerator Physics and Cosmology If SUSY neutralino responsible for Dark Matter in the Universe may get discoveries in direct searches and Tevatron and expect highly significant signals at LHC; But to fully understand role of newly discovered particles in determining the Dark Matter, is crucial to achieve the accuracy provided by the ILC in studying its microscopic properties and those of other particles relevant in defining its relic density.

7 Dark Matter Direct Searches Sensitivity of direct DM searches reaching region of interest for SUSY models of neutralino DM; Next generation of Expts to probe models concurrently with LHC; If WIMP is light may get estimate on its mass: CDMS current 25 kg 150 kg 1000 kg

8 Dark Matter Direct Searches and Tevatron Experiments at Tevatron currently probing high energy frontier searching for SUSY signals; LSP-nucleus scattering through t-channel A 0 exchange correlates DM direct searches to collider search for heavy SUSY Higgses; Exclusion regions for discovery of at Tevatron (2 x 4 fb -1 ) Negative CDMS results reduce likelihood of heavy SUSY Higgs discovery at Tevatron, while CDMS signal would make Tevatron discovery likely. Carena, Hooper, Skands, hep-ph/

9 International e + e - Linear Collider E cm adjustable from GeV Luminosity cm -2 s -1 Ldt = 500 fb -1 in 4 years Energy stability and precision < 0.1% Electron polarization of at least 80% Upgradeable to 1 TeV 2 IRs, tunnel dimensioned for 0.5 TeV ILC Baseline Design defined at Frascati GDE Meeting in December 2005

10 The GDE Plan and Schedule Global Design Effort Project Baseline configuration Reference Design LHC Physics Technical Design ILC R&D Program Bids to Host; Site Selection; International Mgmt from B. Barish

11 LHC Sensitivity Inclusive SUSY Sensitivity in Jets+E T miss Higgs Bosons Sensitivity in M A -tan β A 0 Funnel Region co-annihilation Region modified from S. Abdullin M.B., Hinchliffe, Tovey + ATLAS LHC reach limited towards high end of Focus Point Region where strongly interacting superpartners become too heavy to be produced.

12 Model-dependent LHC Measurements Availability of decay chains with multi-leptons, lepton+jets topologies allows to determine masses from kinematical endpoints (but significant correlations from sensitivity to mass differences): ATLAS Full Simulation Model-dependent Ω CDM predictions can be obtained, in some regions by reconstructing cmssm parameters from observed endpoints: SPS1a: δω/ω = (stat.) 300 fb -1 Polesello, Tovey, hep-ph/ LHC SPS1a cmssm

13 Model-independent LHC Measurements Determine sparticle masses from kinematical edges, neutralino mixing matrix from mass differences, tan β from Higgs sector and bound A mass; Benchmark point strongly constrained by measurements offer good accuracy in full MSSM: δω/ω=0.1 (stat)+/-0.1 (tan β)+/-0.04 (m(τ 2 )) ATLAS 300 fb -1 MSSM LHC SPS1a Nojiri, Polesello, Tovey, hep-ph/

14 ILC Measurements Colliding elementary particles of well defined, tunable energy, quantum Numbers ILC will allow to study production and decay properties of SUSY particles up to kinematical threshold (~500 GeV); Direct access to weakly interacting SUSY particles; Masses determined to O(0.1%) from kinematics and threshold scans; Couplings and quantum numbers measured using decay properties and production cross sections with polarized beams. Geant 4 simulation of heavy neutralino production in LDC detector

15 ILC-LHC Complementarity ILC precision and versatility crucial in extending discoveries and fully testing nature of physics at the new frontier first explored by the LHC: SUSY offers interesting template for complementarity in new particles to be discovered at LHC and ILC, but also for higher sensitivity to Cosmology-motivated scenarios at edges of phase space; ILC offers unique probe in measuring quantum numbers and coupling and thus unravel relation of new signals to Supersymmetry, Extra Dimensions and other scenarios

16 Bulk Point LCC1 In bulk region LSP mostly bino and DM density controlled by annihilation to leptons via slepton exchange: need to determine LSP and slepton masses but also ensure no other mechanisms contribute.

17 A Comparison of DM density accuracy at LHC and ILC in Bulk Region WMAP

18 Focus Point LCC2 In focus point DM density controlled by LSP annihilation to WW and ZZ, large mass splitting between gauginos and sfermions: While focus point always present, its localization in terms of m 0, m 1/2 depends crucially on m top m top Sensitivity

19 ILC Measurements at LCC2 Study of Focus Point at 0.5 TeV is based on five main reactions: e+e- χ + 1 χ 1, χ+ 1 χ 2, χ0 1 χ0 3, χ0 2 χ0 3, χ0 3 χ0 4 Determine mass differences from endpoint of ll and jj distributions and use kinematics to fix masses: Availability of polarised beams provides additional observables for establishing properties of gauginos; Alexander et al. ll Inv. Mass (GeV)

20 co-annihilation Point LCC3 DM density controlled by stau-lsp mass splitting and µ: sensitivity to small M depends on γγ background rejection:

21 LHC Measurements at LCC3 Analysis based on giving final states select signal events based on visible P t >20 GeV with ~50% efficiency and determine M from di-tau mass assuming gluino mass measured: ATLAS Fast Simulation Arnowitt et al., ArXiv:hep-ph M/M = 0.12 (stat) +0.14% (gluino)

22 ILC Measurements at LCC3 At 0.5 TeV production of τ 1 τ 1 and χ 1 χ 2 resulting in ττ E missing final state; Important to reject γγ bkg ee eeττ by low angle electron tagging: Determine M(τ 1 ) - M(χ 10 ) from distribution of M(j 1 j 2 E missing ) Very Fwd. calorimetric coverage controls minimum reachable M: M/M = 0.10 (stat.) Dutta, Kamon, SUSY05

23 A 0 Funnel Point LCC4 DM density controlled by M(A)/2M(χ), Γ(A) and µ requires intensive program of measurements from 0.35 TeV to 1.0 TeV:

24 ILC Measurements at 0.5 TeV Determine M(τ 1 ) and M(τ 1 ) - M(χ 10 ) from stau threshold scan and stau decays; Estimate Γ(A 0 ) from precise determination of BR(h 0 bb) at 0.35/0.5 TeV; Stau Threshold Scan M(j 1 j 2 E missing ) M.B. hep-ph/

25 ILC Measurements at 1 TeV Determine M A from reconstruction in 4-b jet events at 1 TeV; Apply 4C constraints and determine M A and Γ A from 5-par fit to M jj spectrum using signal + quadratic background term: Determine M(χ 3 )-M(χ 1 ) from Z energy distribution in χ 3 χ 1 Ζ decays in χ 3 χ 2 events to fix µ value; At LHC M(A) measurable to 2 GeV but difficult to control Γ(A) and µ Entries / 2 ab Entries / 2 ab Fast Simulation Fast Simulation 100 HA Signal + Bkg 100 HA Signal + Bkg SM Background SM Background Mass (GeV) 500 Mass (GeV) M.B. hep-ph/

26 Dark Matter, SUSY and EGRET Possible interpretation as γ rays from DM annihilation defines new constraints and highlights specific cmssm regions; DM density controlled by χχ annihilation into bb pairs with gaugino cascade decays with real Z and W, well suited to ILC analysis: -6 m 1/2 E 2 * flux [GeV cm -2 s -1 sr -1 ] χ 2 : 9.5/7 χ 2 (bg only): 111.3/8 bb m h < GeV m A = 2 m χ boost > 100 excl. LSP no EWSB EGRET background signal bg + sig E [GeV] de Boer, SUSY M.B., L. Tompkins, M Freytsis m 0

27 Constraining tan β at 1 TeV 2 h Ω χ Points at large tan β, such as LCC3 and LCC4 and EGRET compatible region have large sensitivity on tan β; EGRET Region 2 h 0.25 Ω χ LCC 4 Point BR(H + τν) vs. tan β tan β tan β e+e- H+H- tbτν sensitive to tan β process produced with typical cross section of ~ 2 fb at 1 TeV giving BRs accuracy of O(3-6%).

28 Markov Chain Scans of MSSM Scan MSSM 24-parameter phase space using Markov Chain Monte Carlo technique: given a point i advance to new point i+1 if i) or ii) > rndm() where defined by SUSY measurements and anticipated accuracies; Markov Chain technique more efficient and has better statistical weight of relevant regions and can reach into topologically disconnected regions; µ LCC2 LHC Plot probability density function of Dark Matter relic density and other quantities based on LHC and ILC measurements. M 1

29 Collider Experiments on Dark Matter Dark Matter Density Baltz, M.B., Peskin, Wiszanski,hep-ph/

30 Collider Experiments on Dark Matter Effective Local WIMP Flux at Earth Baltz, M.B., Peskin, Wiszanski,hep-ph/

31 SuperWIMP Dark Matter at Colliders Possible scenario with WIMP decaying into superwimp, such as: long lifetime (~1 yr) WIMP produced at colliders could be detected as heavy charges particle in dedicated setup, its lifetime and mass difference to the Gravitino measured; J. Feng et al. hep.ph/

32 non-susy WIMP Dark Matter Several scenarios of New Physics may include a symmetry protecting a cold DM candidate: Warped Extra Dimensions, Radions, Universal Extra Dimensions,... Servant UED interesting case study, with a phenomenology close to SUSY and particle at a mass scale below 1 TeV to comply with WMAP constraint. CLIC Study Group Tait, Servant

33 UED at High Energy LC UED phenomenology closely resembles SUSY; If UED related to DM density expect signals at LHC, at a multi-tev LC, such as CLIC and possibly a 1 TeV ILC; Events / 1 GeV CLIC 3 TeV KK Particle masses determined very accurately, if kinematically accessible: M.B. et al, JHEP 0507:033, p Lepton (GeV)

34 UED at High Energy LC Nature of new particles can be clearly identified by a spin analysis, based on production properties and decay angles. Entries / 0.1 ab UED SUSY M.B. et al, JHEP 0507:033, cos θ µ cos θ

35 Understanding the nature of Dark Matter will require combination of data from satellites, direct searches and collider experiments; LHC expected to provide a major breakthrough by discovering signals of New Physics beyond the Standard Model and provide first quantitative data on dark matter candidate; A sample of scenarios, widely different in terms of phenomenology and requirements shows that the ILC has the capabilities to promote the study of SUSY Dark Matter to an accuracy comparable to that of present and future satellite CMB data.