Constraints on Darkon Scalar Dark Matter From Direct Experimental Searches

Transcription

1 Constraints on arkon Scalar ark Matter From irect Experimental Searches Based on PhysRev (arxiv: [hep-ph]) Ho-Chin Tsai National Taiwan University in collaboration with Xiao-Gang He, Tong Li, Xue-Qian Li, Jusak Tandean KEKPH09, 6 Mar 2009

2 Outline 1. Introduction 2. SM+ 3. THM II + 4. Conclusions

3 1. Introduction

4 Weak Interacting Massive Particles Observations indicate two large portion energy is unknown, dark. ark matter is cold (nonrelativistic), stable (longlived) and weakly interact still unidentified Too many for me to recognize them Many models are proposed and categorized into, Axions, Weakly Interacting Massive Particles (WIMPS), Lightest Supersymmetric Particle, Lightest Kaluza- Klein Particle, SIMPs, CHAMPs, SIM, WIMPzillas, Scalar M, Light M, also Modified Newtonian ynamics (MON) We focus on a real SM gauge singlet scalar field first proposed by V. Silveira and A. Zee (1985) which is the simplest model with a WIMP candidate, dubbed darkon.

5 Cold ark Matter Relic ensity To a good approximation the CM thermal relic can be calculated by (E.W.Kolb and M.Turner) T ~ m / 20,( x = m / T ~ 20) f f f Ω = 0.105(8) h 2 PG 2008 (1sigma)

6 WIMPs pair annihilation WIMP-Nuclei elastic scattering

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9 2. Standard Model + arkon

10 SM + Scalar Gauge Singlet arkon Standard Model Lagrangian (for demonstration only, color d.o.f. suppressed) + arkon Lagrangian Coupled to Higgs fields only To play a role of cold dark matter and restricted by renormalizability stable Z 2 symmetry to annihilate in pairs, weakly interact gauge singlet, no VEV to decay like Higgs, relic determine darkon-higgs coupling ( < 1 to be calculated perturbatively)

11 Features of arkon Sector Other SM sectors remain intact The darkon Lagrangian after SSB is 1 ( ) 1 L = λ + m0 + λv + λh + λvh m Interact with SM through Higgs

12 Coupling Numerical in SM+ With darkon Lagrangian determined, annihilation rate can be calculated f, V,V* s = 2m f, V,V* is virtual Higgs with mass The value of darkon-higgs coupling is inferred by reproducing the correct relic 1. Larger Higgs width smaller darkon coupling. 2. ips at m = mh /2. 3. Other effects can be calculated by known coupling, e.g. darkon-nucleon cross-section.

13 ark Matter irect Search Experiment To compare the experimental upper limits of spin-independent WIMP-nucleon elastic scattering cross-section λ h v h N g NNH Effective Higgs-nucleon coupling is needed N A barn is cm 2, approximately to the cross sectional area of a uranium nucleus 100 fm 2. ħ2 c2 GeV2, 1/GeV 2 =0.3894mb

14 Effective Higgs-Nucleon Coupling N h, H g NNH In SM or THM II N The coupling g NNH depends on its underlying Yukawa couplings Generic Yukawa couplings k SM u SM = k = 1 d Since the recoil energy of nuclei is low < 100keV we can use the chiral Lagrangian method to obtain the coupling g NNH physical mass of nucleon baryon mass in the chiral limit Numerically by adopting

15 Results in SM+ Background + signal describe EGRET data! by W. de Boer et al. Background + MA signal describe EGRET data! 50 GeV π 0 IC WIMPS Brems. π 0 IC WIMPS Brems. IC 70 Blue: background uncertainty Blue: WIMP mass uncertainty arkon mass of 10~(50,70, 80) GeV at Higgs mass (120, 200, 350)GeV is ruled out by upper limit 90% C.L. curves arkon as a potential explanation of the gamma ray excess observed by EGRET experiment which compatible with a dark matter with a mass in the range of 50 to 70 GeV Extend SM+ to two Higgs doublet model II plus a darkon (THMII+)

16 3. Two Higgs oublet Model II + arkon

17 Two Higgs oublet Model II + arkon Lagrangian in THM+ are by an analogy to SM+ argument Writing Higgs fields in component form we have H k + 1 2h k = 2 vk hk ii + + k Charged and imaginary components in term of physical Higgs H^+, A and would be goldstone boson z, w + + h cos sin 1 β β w + = + h sin β cos β 2 H I1 cos β sin β z = I 2 sin β cos β A where tan β = v1/ v2 Neutral Higgs mass eigenstates H and h h1 cosα sinα H = h 2 sinα cosα h

18 arkon Mass and Couplings arkon terms with of physical degree of freedom -- there is no A 2 couplings. -- since m, 0 λ, 1 λ, 2 λ3 are free parameters, we can treat as new free parameters m, λ, λ h H Two channels h, H for darkon pair annihilations can be calculated with Yukawa couplings known In quark degrees of freedom λ h v, H f f, V,V*,. f, V,V*,..

19 THM Type I, II, and III There are tree types of THM distinguished by Yukawa couplings THM type I -- second doublet couples to two iso-spin sectors, so couplings are unchangeable ( being fixed, like SM+ ) THM type II second Higgs to up and first to down sector THM type III, too many parameters and FCNC So we will only consider THM II further with an Z_2 symmetry to separate H1 H2 contributions

20 Yukawa Couplings (THM II) The Yukawa couplings of THM II are The ks can be read off λ h v h, H λ h v, H f, V,V*,. N g NNH N f, f V,V*,..

21 N-N Elastic Scattering in THM II+ Elastic scattering formula in THM II + h, H arkon-nucleon Coupling N g NNH N k-coefficients of THM II For simplicity drop H contribution by assuming H very small or H large λ m Coupling can vanish at tanα tan β = 0.405

22 Couplings in THM II+ We demonstrate two cases with partial cancelation in stead of tanα tan β = Larger virtual Higgs width implies smaller. And dips at m = m /2. λ h h

23 N-N Results in THM II+ The partial cancellation makes THM II+ escape the XENON and CMSII 2008 constraints Future experiments can give more stringent constraints SuperCMS at Soudan, SuperCMS at Snolab, and XENON

24 TEXONO, Small arkon Masses The TEXONO Collaborations explore the small darkon mass region but so far not constrain darkon. Their coming ultra low energy germanium detector (ULEGe) experiment can be sensitive enough

25 4. Conclusions

26 Conclusions SM+ with darkon mass in the range of 10~(50,70, 80) GeV at Higgs mass (120, 200, 350) is ruled out by XENON and CMSII The effective Higgs-Nucleon coupling in THM II+ can vanish due to some cancelation. The darkon mass region in SM+ excluded by XENON and CMSII 2008 can be restored in THM II+ extension. The future experiments XENON100 and SuperCMS can set stronger constraints. arkon dominated Higgs invisible width is implied and can be probed through missing energy processes at LHC.

27 Search arkon at LHC ALTLAS can study invisible Higgs decay signal by looking for missing energy of the Higgs decay from weak boson fusion processes. With this large invisible BR darkon can be probed by comparing to the SM invisible Higgs decay prediction at LHC. Invisible BR between 0.3 to 0.6 with m h > 160 GeV can be studied even with 30 fb 1 at ALTLAS. 1 With 300 fb, m 2m, say m = 300 GeV, the total width can be determined to an accuracy of 10%.. h Z h

28 Enhance Higgs Invisible Width Fsmall m, h dominate the decay, being stable so invisible. Make exclusive Higgs search harder. The total decay width is increased considerably to make resonance reconstruction more difficult. The increasing of the invisible width of Higgs boson can be compared with the SM prediction to probe the existence of darkon. Large m the h contribution become small and the Higgs decay is more SM like.