Yoshitaro Takaesu U. of Tokyo LHC limits on the Higgs-portal WIMPs arXiv: in collaboration with M. Endo (U.Tokyo)

Portal models to Hidden Sector 2 Consider another world where particles are SM singlets (Hidden Sector). The particles interact to our SM world through Gravity. Also, they may interact through… DM ? Neutrino Portal Vector Portal Axion Portal Higgs Portal Sterile neutrino Dark Photon Axino-like particle Higgs invisible decay SMHidden G In this talk, we discuss the Higgs-portal possibility.

Constraints on Higgs-portal models 3 Relic abundance Direct detection Collider search Tight constraints on Higgs-portal “DM”. Still important to know to what extent LHC can explore the heavier Higgs-portal models. Heavy Higgs-portal WIMP search [Simone, Giudice, Strumia: ] Need not to be the DM

Collider search for Heavy Higgs-portal WIMP 4

Higgs-portal models to be studied 5 Scalar Vector Anti-sym. Tensor are SM singlets. parity is assumed for and to ensure their stability. after EWSB Fermionic hidden particle is not considered for simplicity. ( SM singlet is stable without imposing parity by hand ) [A. Djouadi et al , S.Kanemura et al ] [O.Cata, A. Ibarra: ]

Cross section of WIMP-pair production 6 We can express the WIMP pair production cross section as This is the basic formulae for our analysis.

Experimental searches 7 VBF Higgs invisible decay Mono-jet Mono-Z

Searches for Higgs invisible decay at the LHC 8 Vector Boson Fusion (VBF) BR_inv < 0.65 [CMS: 8TeV 19.5 fb^-1: ] Z associated production (ZH) BR_inv < 0.75 [ATLAS: 8TeV 20.3 fb^-1: ] BR_inv < 0.81 [CMS: 8TeV 19.5 fb^-1: ] Good S/B (Z-mass constraint, 2-lepton +missing) Cross section is small (Useful at high luminosity) 2 nd largest Higgs production process Good S/B (large rapidity gap of 2 energetic forwarding jets)

Mono-X searches 9 Mono-X searches (X +missing pT) are also sensitive to Higgs-portal models. Mono-jet Large Cross section Main mono-X mode so far S/B is not good Gluon-fusion Higgs production Mono-Z Same topology as ZH for Higgs-portal model Mono-lepton Mono-photon Mono-top Mono-Higgs etc …

VBF analysis (CMS, ) 10 We calculate under the following cuts (w/ MCFM-6.8): Compare to the upper bound on the signal events. 95% CL upper bound

8 TeV LHC constraints 11

Limits for the Heavy Higgs-portal WIMPs 12 TensorVector Scalar Data : BG VBF 390 : 332(58) Mono-jet 1772 : 1931(131) Mono-Z 45 : 52(18)

14 TeV LHC prospects 13

How to perform (rough) projection 14 We need to know and to estimate the 14 TeV constraints on. is roughly estimated with the following assumptions: 95% CL (simple Gaussian) Relative does not improve Relative reduces as. increases due to PDF (luminosity ratio) and integrated luminosity is estimated by theoretical calculations with experimental cuts.

Sensitivity Summary (Mono-j, VBF, Mono-Z) 15 MJMZVBF MJMZVBFMJMZVBF * Rough Estimate Tensor MJMZVBF

Summary 16 LHC constraints on the Heavy Higgs-portal WIMP have been Studied. 8 TeV LHC results can access the Higgs-portal couplings below 1 for the vector and tensor case. Scalar coupling limit is very weak. 14 TeV LHC can reach at O(0.1) couplings for vector and tensor case. The scalar coupling below O(1) will be remained unexplored. VBF channel already shows good performance in 8 TeV LHC, replacing the mono-jet channel. ZH, Mono-Z channel will also be a important channel in 14 TeV LHC.

Backup Slides 17

Mono-jet analysis (CMS-PAS-EXO ) 18 We calculate under the following cuts (w/ MCFM-6.8): Taming the infinite top mass effects Avoiding large region giving the most stringent limit (* 2 nd jet with pT > 30 GeV (from NLO real emission) is not vetoed, due to technical reason. )

Mono-jet analysis 19 We would like to evaluate the cross section at least NLO QCD order. However, NLO cross sections are only known in limit. We approximate the NLO cross section as LO K-factor [R.V.Handler et al ] [L.Altenkamp et al ]

20

21

Mono-Z analysis (ATLAS, ) 22 We calculate under the following cuts (w/ HAWK-2.0): giving the most stringent limit

Mono-jet channel: 14 TeV LHC 23 Cross Sections at 14 TeV Cx < 1 (100 1/fb) Cx < 0.2 (100 1/fb)

Mono-Z channel: 14 TeV LHC 24 Cross Sections at 14 TeV

VBF and ZH channels 25 [5] ATLAS, [6] CMS, [16] D.Gosh et al., [17] ATL-PHYS-PUB [18] Snowmass, % Upper bounds on the Higgs inv. decay ratio at mH = 125 GeV The VBF bound will be improved by a factor of 4 at mH = 125 GeV. The Upper bound on improves a factor of 2. The ZH bound will be improved by a factor of 2 ~ 4 (300 1/fb) and 4 ~ 12 (3,000 1/fb). The Upper bound on will be improved by a factor of 1.5 ~ 2 (300 1/fb) and 2 ~ 3.5 (3,000 1/fb). If this level of improvement holds for any mH, the Upper bound on improves a factor of 4. Profile-based Cut-based

Higgs production Cross Sections Gluon-fusion VBF WH ZH

27

28

29

30

31

32

33

34

35

How to estimate 36

37

archive 38

We will investigate the constraints of the LHC invisible searches on Heavier Higgs-portal WIMP models.

Mono-X searches 40 Mono-X searches (X +missing pT) are also sensitive to Higgs-portal models. Mono-jet Large Cross section Main mono-X mode so far S/B is not good Gluon-fusion Higgs production Mono-Z Same topology as ZH for Higgs-portal model Mono-lepton S/B is good Cross section is small Useful for high luminosity WH production

Direct searches for Higgs invisible decay at the LHC 41 Vector Boson Fusion (VBF) BR_inv < 0.65 [CMS: 8TeV 19.5 fb^-1: ] Z associated production (ZH) BR_inv < 0.75 [ATLAS: 8TeV 20.3 fb^-1: ] BR_inv < 0.81 [CMS: 8TeV 19.5 fb^-1: ] Good S/B (Z-mass constraint, 2-lepton +missing) Cross section is small Useful for high luminosity 2 nd largest Higgs production process Good S/B (large rapidity gap of 2 energetic forwarding jets) SM prediction: Sizable BR_inv is an evidence of BSM models!

Mono-jet Sensitivity 42 * Rough Estimate Tensor

Sensitivity Summary (Mono-j, VBF, Mono-Z) 43 * Rough Estimate

How to perform (theorist’s) projection 44 We need to know and to estimate the 14 TeV constraints on. is roughly estimated with the following assumptions: 95% CL (simple Gaussian) does not improve reduces as increases due to PDF (luminosity ratio) and integrated luminosity is estimated by theoretical calculations with experimental cuts. 8TeV data

How to perform (theorist’s) projection 45 We need to know and to estimate the 14 TeV constraints on. is roughly estimated with the following assumptions: is estimated by theoretical calculations with cuts.

Searches for Higgs invisible decay at the LHC 46 Vector Boson Fusion (VBF) BR_inv < 0.65 [CMS: 8TeV 19.5 fb^-1: ] Z associated production (ZH) BR_inv < 0.75 [ATLAS: 8TeV 20.3 fb^-1: ] BR_inv < 0.81 [CMS: 8TeV 19.5 fb^-1: ] Good S/B (Z-mass constraint, 2-lepton +missing) Cross section is small Useful for high luminosity 2 nd largest Higgs production process Good S/B (large rapidity gap of 2 energetic forwarding jets) SM prediction: Sizable BR_inv is an evidence of BSM models

Direct searches for Higgs invisible decay at the LHC 47 Upper bounds on the BR_inv have been obtained using invisible decay modes Vector Boson Fusion (VBF) BR_inv < 0.65 [CMS: 8TeV 19.5 fb^-1: ] Z associated production (ZH) BR_inv < 0.75 [ATLAS: 8TeV 20.3 fb^-1: ] BR_inv < 0.81 [CMS: 8TeV 19.5 fb^-1: ] Good S/B (Z-mass constraint, 2-lepton +missing) Cross section is small Useful for high luminosity 2 nd largest Higgs production process Good S/B (large rapidity gap of 2 energetic forwarding jets) Useful for high luminosity

Caveats: Constraints on Higgs-portal DM models 48 Relic abundance Direct detection Collider search Tight constraints on Higgs-portal DM. Collider search is powerful, but Heavy Higgs-portal WIMP direct detection Small abundance Heavy Higgs inv. decay [Simone, Giudice, Strumia: ]

Constraints on Higgs-portal DM models 49 Relic abundance Direct detection Collider search There are severe constraints on the Higgs-portal DM models. However, this is applicable only if the hidden particle is the dominant component of the DM. Not rule out less abundant components (Higgs-portal WIMPs) at the same level. Collider WIMP searches is the right way for such possibilities.

Interpretation for Higgs-portal WIMPs 50 How about for Heavier Higgs-portal DMs? No explicit analysis. We will try to re-interpret the direct Higgs invisible decay and mono-X limits for Heavier DM case.

Indirect searches for Higgs invisible decay 51 ATLAS-CONF The ATLAS and CMS collaborations have used the visible decay modes to infer limits on the invisible branching fraction of the 125 GeV Higgs boson: ATLAS: upper limit of 60% (ATLAS-CONF ) CMS: upper limit of 64% (CMS-PAS-HIG )

Limits for the Heavy Higgs-portal WIMPs 52 Data : BG VBF 390 : 332(58) Mono-jet 1772 : 1931(131) Mono-Z 45 : 52(18)

Sensitivity Summary (Mono-j, VBF, Mono-Z) 53

Tensor Sensitivity (Mono-j, VBF, Mono-Z) 54 14T * Rough Estimate Mono-jet Mono-ZVBF 14T T T T T T T T T

Tensor Sensitivity (Mono-j, VBF, Mono-Z) 55 * Rough Estimate

Higgs is more and more SM like 56 Is there any room for BSM physics in higgs property measurements?

Direct searches for Higgs invisible decay at the LHC 57 Higgs is more and more SM like. But there are still room for New Physics. Higgs invisible decay width still allows New Physics (NP) contributions a lot. SM prediction is small: Sizable BR_inv is an evidence of BSM models!

Higgs width measurements 58 Higgs width is less constrained among Higgs properties.

Direct searches for Higgs invisible decay at the LHC 59 Higgs is more and more SM like. But there are still room for New Physics. Higgs invisible decay width is such a place : [ATLAS: ] [CMS: ] Higgs invisible decay width allows New Physics (NP) contributions. SM prediction is small: Sizable BR_inv is an evidence of BSM models!

Cut-based vs. profile-based analysis 60 In this study, we re-interpret the latest cut-based results of 8 TeV LHC for each channel. Cut-based analysis Profile-based analysis Both analysis set limits on pp > chi chi +X (X = j, jj, Z, …) cross section, but profile-based analysis limits are depend on the topology, on-shell higgs production with m_H and its decay to DM pair.

Cut-based vs. profile-based analysis 61 In this study, we re-interpret the latest cut-based results of 8 TeV LHC for each channel. Cut-based: Use event numbers after experimental cuts (one-bin analysis) Topology independent (only uses cross section information) Weaker limits than profile-based analysis Profile-based: Use event distributions after experimental cuts (multi-bin analysis) Topology dependent (distribution changes for different topologies) Stronger limits than profile-based analysis Both analysis set limits on pp > chi chi +X (X = j, jj, Z, …) cross section, but profile-based analysis limits are depend on the topology, on-shell higgs production with m_H and its decay to DM pair.

62 We use Profile-based analysis put limits on the cross sec * BR and is depend on the higgs mass. Need to convolute in the above integration for the heavy DMs. But those limits are limited up to m_H < 150 GeV. Difficult to re-interpret profile-based limits. So, we restrict our analysis to use only cut-based results: VBF, mono-jet, mono-Z searches. Obtained constraints is conservative limits for the 8 TeV LHC. Profile-based analysis optimized to the heavy higgs-portal DMs will give more stringent constraints.