1. 1 Determination of Dark Matter Properties in the Littlest Higgs Model with T-parity Masaki Asano (SOKENDAI) Collaborator: E. Asakawa (Meiji-gakuin), S. Matsumoto, T. Kusano,Y. Takubo (Tohoku)

2. 2 Dark Matter Hierarchy Problem + m02m02 Λ 2 correction m h 2 = related to quadratic divergence to the Higgs boson mass term.  Fundamental particle  composite particle The quadratic divergence has to be removed. SUSY There is no fine-tuning problem, if Λ ～ 1TeV LH Experimental results require R.Barbieri and A.Strumia (’00) SM is the successful model describing physics below ~ 100 GeV. But, Little hierarchy prob.

3. 3 Dark Matter Existence of cold dark matter is established by WMAP. WIMP are CDM candidate.  Neutral  Massive  Stable http://map.gsfc.nasa.gov/ However, There is no WIMP in the SM. (Weakly Interacting Massive Particles) ~ 0.1 the dark matter should be included in physics beyond the SM at TeV Hierarchy Problem + m02m02 Λ 2 correction m h 2 = related to quadratic divergence to the Higgs boson mass term.  Fundamental particle  composite particle The quadratic divergence has to be removed. SUSY There is no fine-tuning problem, if Λ ～ 1TeV Experimental results → LH R.Barbieri and A.Strumia (’00) SM is the successful model describing physics below ~ 100 GeV. But, Little hierarchy prob.

4. 4 Introduction Details of the Littlest Higgs model with T-parity Process and sample points Simulation results and cosmological connection summary The Littlest Higgs Model with T-parity is a new possibility for physics at TeV. This model can solve the little hierarchy problem. Moreover, there are new particles ( e.g. W H, Z H, …) including a DM candidate (A H ). We study the collider phenomenology of new particles in this model, and estimate the accuracy of extracted new particle mass (We mainly consider e+e-  W H W H process in this study). Using this result, we reproduce the DM relic abundance which can be compared with cosmological observations. Plan

5. 5 non-linear sigma model describing SU(5)/SO(5) symmetry breaking fermion EW gauge Higgs H ΦHΦH m ∝ f W SM WHWH ψ SM ψHψH Littlest Higgs Model with T-parity top t SM T+T+ T-T- tHtH t-T + mixing Little Higgs Mechanism Higgs is the pseudo Nambu-Goldstone boson Quadratic divergences to Higgs mass term completely vanish at one-loop level (collective symmetry breaking). W h h g2g2 + WHWH h h – g 2 e.g. N. Arkani-Hamed, A. G. Cohen, H. Georgi ( ’ 01) gauge group [SU(2)×U(1)] 2 VEV f ~ O(1) TeV SU(2)×U(1) U em (1) 〈 h 〉 NEW T-even T-odd T-Parity (Z 2 symmetry) ZHZH SM particle H. C. Cheng, I. Low ( ’ 03) dark matter candidate SM particles T-even New particles T-odd To confirm the Littlest Higgs model with T-parity, We should measure the parameters f. We will measure f using e + e - → W H + W H - in ILC.

6. 6 J.Hubisz and P.Meade (‘05) Allowed region for WMAP Lightest T-odd particle: A H 0.1 1 10 (TeV) W, Z h AHAH W H, Z H Φ Spectrum T-evenT-odd Lightest T-odd main ~g’ 2 /v ~m W 2 /v A H annihilates into W, Z In each branch, m h is determined by f. Relic density depends only on f & m h U-branch L-branch Allowed region for WMAP at 2σlevel Relic abundance M. A, S. Matsumoto, N. Okada, Y. Okada PhysRevD.75.063506

7. 7 Process & Sample Points  H, W H ±, Z H, Φ Gauge-Higgs sector Top sector t – T – b–b– ・・・ fermion sector T-odd In this model, there are many new heavy particles.

8. 8 Direct production of A H (e.g. e+e-  A H Z H ) will be possible in ILC.  Because AH is missing particle, it is slightly difficult to measure mA H precisely. Kusano san’s talk W H W H production (e.g. e+e-  W H W H  WWA H A H ) will be possible in the area. Relic abundance Which particle can produced at the ILC ? → It depends on VEV f.

9. 9 Direct production of AH (e.g. e+e-  A H Z H ) Kusano san’s talk WHWH production (e.g. e+e-  W H W H  WWA H A H ) will be also possible in the area.  we can measure the mAH precisely using the two standard weak gauge boson. Relic abundance Which particle can produced at the ILC ? → It depends on VEV f. We study the WHWH pair production process. Qing-Hong Cao et. al. 0707.0877  In this region, Higgs mass is also small. Small Higgs mass region is also favored by EW Precision Measurements.

10. 10 All sample points satisfy all experimental & cosmological constraints. Heavy gauge bosons turns out to be less than 500 GeV.  It is possible to produce them in pair at the ILC. We focuse on WHWH process in 1 TeV ILC. Our sample points f F O (f) O (v) Dark Matter 500 GeV Mass spectrum

11. 11 Simulation at ILC 125 GeV 375 GeV II e + e –  W + W – A H A H E W (energy of W) [GeV] Integrated Luminosity: 500fb - We have done the simulation using CalcHep. Because the simulation shows end points clearly, It allow us to extract the property of DM. f = 656.1 [GeV] f = 660 [GeV] δ= 0.6% accuracy From this E W, we get DM mass is determine less than 2% accuracy. [Model dependent]

12. 12 Because DM mass and Higgs mass is determined precisely, the DM abundance is also determined precisely less than 2%. It is possible to consistency check of the model using PLANCK. 96 98 100 94 92 0.10 0.09 0.11 0.12 ILC PLANCK WMAP mAH [GeV] Ωh 2 Cosmological Impact We reproduce the DM abundance from parameters which will be determined by ILC.

13. 13 Littest Higgs model with T-parity is one of attractive models for physics beyond the SM. From the WMAP observation, heavy gauge bosons will be copiously produced at the ILC. e + e - → W H W H is the best process to investigate the property of the DM predicted in the model. Simulation shows the clear edge in signal events, which allow us to extract the model parameters precisely. Results obtained from the collider experiments will be compared to those from astrophysical experiments DM abundance is determined precisely with uncertainty which less than 2%. It is possible to consistency check of the model using PLANCK. Summary