Di-Higgs Production

New boson → New Probe for BSM Increase in collision energy → Higher sensitivity

Search for BSM with Higgs final states!

Cigdem Issever

Transition from Run1 to Run2

Oxford’s Exotics Group’s Run1 activities Resonance Searches and Threshold Effects

Dijet final states mjj ~ 5 TeVLeading ATLAS dijet search paper (Kate)

Dijet Angular distribution searches (Ryan)Boosted ttbar final states (Jiahang, Sarah, Katharina)

Jiahang: Exotics HQT convener Performance work

Jet algorithms (Lucy, Katharina, Jeff,Cigdem)Jet calibration (Lucy)Jet punch-through (Shaun, Todd)

C. Issever, University of Oxford 2

Direct Searches for BSM → 2H

Resonance Searches CMS excludes < 360 GeV

CMS-PAS-HIG-13-025 Two Higgs Doublet Models (2HDMs) Multi-lepton final states

ATLAS excludes < 790 GeV ATLAS-CONF-2014-005 2H →4b, resolved KK Graviton G* → 2H →

C. Issever, University of Oxford 3

m(HH)m(X)

Num

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f obs

erve

d ev

ents

Oxford Run2 Plans: Search for BSM in 2H → final states• Semi-boosted regime: 150 GeV < pT(H) < 250 GeV

• Boosted regime: pT(H)>250 GeV

• Matches our Run1 experience: dijet and ttbar searches, jets

Non Resonant Searches

Assume BSM sector is heavy → HEFT Deviations in kin. distributions and cross sections predicted

Search for deviations from the expected shape mHH

Pt(H) …

C. Issever, University of Oxford 4

Non-Resonant Searches

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Towards end of Run2 – Higgs Self coupling Currently studies suggest 600 fb-1 needed.

Assumes state of the art experimental techniques Uses easy final states with low backgrounds 4b high rates – backgrounds a problem

Group is working and developing new techniques Jets Boosted particle ID

Future add Boosted b-tagging Colour flow variables …

Improvement of the state of the art Essential Non-trivial

C. Issever, University of Oxford 6

Feasibility study with Juan

Objectives for Run2

Add Searches in 2H → 4b to Exotics program (potentially also 2b+2W, 2b+2tau) Resonance Non resonance

Measure 2H rate to constrain λ Performance

Jet algorithms (Variable R jets, SC-Jets, see Jeff’s talk) Jet calibration Boosted b-tagging (Variable R TRACKjets) Jet-Pull (colour flow) variables (Background reduction)

C. Issever, University of Oxford 7

C. Issever, University of Oxford 8

Backup Slides

Variable R Jets – boosted tops – jet mass cut

C. Issever, University of Oxford 9

1000 GeV < pTjet <2000 GeV 2000 GeV < pT

jet < 3000 GeV

B-tagging

C. Issever, University of Oxford 10

Colour Flow

C. Issever, University of Oxford 11