The inert doublet model in light of LHC and XENON

Transcription

1 The inert doublet model in light of LHC and XENON Sara Rydbeck 24 July 212 Identification of Dark Matter, IDM 212, Chicago 1

2 The CERN Large Hadron Collider Only discovery so far. If no new strongly interacting physics is found, how can we further test for new electroweak physics at the LHC? At 14 TeV and design luminosity, each experiment should accumulate 1/fb/ year. 2

3 The case for the inert doublet model Based on arxiv: in collaboration with Michael Gustafsson, Laura Lopez-Honorez and Erik Lundström. IDM is a simple extension of the SM that can incorporate dark matter (still needed) a large range of Higgs masses (most probably not needed anymore). With or without a Higgs at ~125 GeV, what is the status of the IDM in light of LHC Higgs-searches and XENON direct searches? What are the prospects for the IDM to show up in the 14 TeV LHC data? 3

4 The Inert Doublet Model (IDM) Deshpande, Ma (1978) An extension of the Standard Model Higgs sector to include a second doublet, odd under a discrete unbroken Z 2 -symmetry ( H 1 and all SM fields even) V = µ 2 1 H µ 2 2 H λ 1 H λ 2 H λ 3 H 1 2 H λ 4 H 1 H λ 5 Re[(H 1 H 2) 2 ] H 2 Only the SM-like Higgs doublet breaks the electroweak symmetry: H 1 = v + h/ (2) The inert doublet develops no vev and does not couple to fermions: H 2 = H + (H + A )/ (2) 4

5 The Inert Doublet Model (IDM) Simple model but rich phenomenology: Can allow for a heavy SM-like Higgs (16-6 GeV) without violating EWPT (improved naturalness?) Barbieri, Hall, Rychkov (26) Gives a viable WIMP dark matter candidate! m 2 h = 2µ 1 =4λ 1 v 2 m 2 H = µ 2 2 +(λ 3 + λ 4 + λ 5 )v 2 = µ λ H v 2 m 2 A = µ 2 2 +(λ 3 + λ 4 λ 5 )v 2 = µ λ A v 2 m 2 H = µ λ 3 v 2 Lopez Honorez, Nezri, Oliver, Tytgat (27) Gustafsson, Lundström, Bergström, Edsjö (27) We take the (CP-even) H to be the WIMP dark matter candidate. We impose conditions on the couplings to ensure vacuum stability, perturbativity and unitarity. 5

6 Constraints on IDM.1 pb Particle data (pre-lhc): 11 1 LEP excluded luded T Oblique parameter constraints A1 A2 C4 C2 C1B2 C3 m h = GeV S B1.8 pb Electroweak precision tests (EWPT) T (m H + m A )(m H + m H ).35 pb.2 pb.15 pb.1 pb.5 pb n cross section Collider upper data limits from as LEP extracted [16]. For models inside the (red) solid ntour the limits are rescaled by a factor ng applied to H A production. The solid Gustafsson et. al. 212 mass H [GeV] LEP I excluded LEP II energy reach m H ± 7 9 GeV Pierce, Thaler (27) mass A [GeV] Gustafsson, Lundström, Bergström, Edsjö (29) FIG. 7: LEP exclusion plot. The (red) dotted-shaded re indicates the region of the (m H,m A )planeexcludedbyl data. The lower left triangle, where m H + m A <m 6 Z excluded by LEP I data on the Z boson width. The remain

7 Constraints on IDM Dark matter: Relic density (WMAP-7) Ω m h 2 =.119 ±.56(1σ) Annihilation via Higgs Larson et. al. (211) Coanniliations m H m A or m H ± SI [cm 2 ] Dark matter direct detection limits 1 4 XENON1 (low mass) IDM XENON1 B2 B1 C2 C3 C4 C1 Gustafsson et al. 212 Annihilation to WW,ZZ,t t 1 48 Direct detection with XENON 1 5 Angle et. al. (211), Aprile et. al. (211) m DM [GeV] A2 A Indirect detection (gamma-ray constraints with Fermi-LAT) Abdo et. al. (21), Ackerman et. al. (211,212) 7

8 Constraints on IDM Allowed dark matter masses before LHC: m H 5 8 GeV new viable region ~1 GeV excluded m H Lopez-Honorez, Yaguna (211) 8 15 GeV SI [cm 2 ] Dark matter direct detection limits 1 4 XENON1 (low mass) IDM XENON1 B2 B1 C2 C3 C4 C1 Gustafsson et al m DM [GeV] A2 A Fermi-LAT collaboration (211) very high mass region ~5 GeV, not accessible at LHC 8

9 The role of multiple leptons at LHC The IDM has been shown before to predict signals in 14 TeV data: in the dilepton plus missing transverse energy channel Dolle, Miao, Su, Thomas (21) pp H A dominating process, m H <m A <m H ± in the trilepton plus missing energy channel Miao, Su, Thomas (21) dominating process pp A H ±,H ± H predict signal at 1-3/fb for needed for a detectable signal. 4 GeV < (m A m H ) < 8 GeV These signals have no direct dependence on the Higgs mass. 9

10 The role of multiple leptons at LHC IDM could give rise to even higher lepton multiplicities in the final state: f f f f q Z/γ/h W + Z A H q H + H W A Z H f f f f The tetralepton plus missing energy channel has very low SM background. t tz, ZW W, ZZ reduced with b-jet veto, Z veto, missing energy, fakes may be important, for example t t 1

11 Production of four leptons via gauge bosons pp H ± A, H + H Depends only on the masses of the inert scalars. m H = 7 GeV f f l l lepton production, log 1 [ /1 fb] q W ± W ± H ± A Z A H l ± ν l + l q Z l l + H q q Z/γ W ± H ± H Z A H H W m H + [GeV] But the signal is weak. l ν m A [GeV] 11

12 Production of four leptons via SM-like Higgs pp A A, H + H m H = 7 GeV, µ 2 2 =,m H ± = 22 GeV Depends also on Higgs mass and coupling lepton production, log 1 [ /1 fb] 1.5 g g h A Z A H H Z l l + l l+ m h [GeV] m A [GeV] Connection to Higgs searches and dark matter direct detection... 12

13 Complementarity of LHC Higgs searches and dark-matter direct detection Higgs portal dark matter: Higgs-DM coupling constrained by direct detection experiments -> restricts the invisibility of Higgs to collider searches In the IDM: Farina et. al. (211), Mambrini (211), Raidal, Strumia (211), Baek et. al. (212), Djouadi et. al. (211), He et. al. (211), Lebedev et. al. (211), Lopez-Honorez et. al. (212), Djouadi et. al. (212) Direct detection constrains the coupling: λ H = m2 H µ 2 2 v 2 We have the relation: λ A = λ H + m2 A m 2 H v 2 The larger these couplings are allowed to be, the larger is the IDM contribution to the Higgs width the production cross section into A A at LHC (for heavy Higgs) 13

14 Complementarity of LHC Higgs searches and dark-matter direct detection With 7 TeV LHC data (~5/fb March 212) and maximum invisible width: Upper/lower limits on the Higgs signal in IDM for different H masses Upper/lower limits for m H = 7 GeV, under different assumptions T 1 m H = 45 GeV m H = 8 GeV m H = 15 GeV Gustafsson et. al a b Gustafsson et. al. 212 c / SM VVV / SM 1 1 Excluded by LHC Higgs searches CMS (dotted), ATLAS (dashed) Lower limits from XENON (H 1% of local DM) for m H = 8, 45, 15 GeV 1 1 Excluded by LHC Higgs searches: CMS (dotted), ATLAS (dashed) Lower limits from XENON for m H = 7 GeV (with H 1% of the local DM) (a) XENON limits shifted by syst. uncert. (b) If H constitutes 1% of the local DM (c) m h [GeV] m h [GeV] This is before checking the relic density. 14

15 16 14 Models with 1 H Gustafsson et. al. 212 Complementarity of LHC Higgs searches and dark-matter direct detection =1 CDM models passing XENON1 models passing LHC Allowed models by XENON+LHC Taking into account also the relic density: mh [GeV] 12 new viable region mh =8-15 GeV can now be ruled out only mh =5-8 GeV for Higgs masses mh [GeV] Intermediate Higgs masses could have been allowed if IDM explains only a fraction of the DM With mh 3-6 GeV, IDM could have been discovered at ~1-2/fb@14TeV. Models with 1H = 1ï1% of 1CDM 14 models passing XENON1 models passing LHC Allowed models by XENON+LHC 12 mh [GeV] we take into account systematic uncert. 16 Gustafsson et. al. 212 ~125 GeV, > 6 GeV (?) mh [GeV] 5 15

16 Complementarity of LHC Higgs searches and dark-matter direct detection Updated ATLAS- and CMS-limits with 8 TeV data: Upper/lower limits on the Higgs signal in IDM for different H masses Upper/lower limits for m H = 7 GeV, under different assumptions 1 m H = 45 GeV m H = 8 GeV m H = 15 GeV Gustafsson et. al a b c Gustafsson et. al. 212 / SM / SM 1 1 Excluded by LHC Higgs searches CMS (dotted), ATLAS (dashed) Lower limits from XENON (H 1% of local DM) for m H = 8, 45, 15 GeV 1 1 Excluded by LHC Higgs searches: CMS (dotted), ATLAS (dashed) Lower limits from XENON for m H = 7 GeV (with H 1% of the local DM) (a) XENON limits shifted by syst. uncert. (b) If H constitutes 1% of the local DM (c) m h [GeV] m h [GeV] On top of there being a really good Higgs candidate at 125 GeV now: Even if DM-density could be lowered even further, couplings are becoming dangerously large (problems with unitarity and perturbativity/triviality) if we are to evade these limits for large Higgs masses. 16

17 Conclusion and outlook IDM before LHC 8 TeV data: Could accommodate a heavy Higgs even though the SM could not. IDM with 1% dark matter and a heavy Higgs (16-6 GeV) could be ruled out by LHC Higgs searches + XENON1 direct-detection searches once all complementary constraints were combined. IDM with 1% dark matter and with Higgs masses 3-6 GeV predicted strong signals in the four-leptons+missing energy channel at LHC 14 TeV. IDM after LHC 8 TeV update and with an SM-like Higgs of ~125 GeV: The prediction for the dark-matter mass in IDM is 5-8 GeV (and LHC unreachable range ~5 GeV). Higgs branching ratios can be altered also at loop level (γγ). Should be searched for in the LHC 14 TeV data in channels with missing energy and two or three leptons. Dolle, Miao, Su, Thomas (21) Arhrib, Benbrik, Gaur (212) See also Andreas Goudelis talk. 17