SUSY Searches with One Photon at CMS

Valentina Sola(Universität Hamburg)

GMSB and GGM Photon Searches at CMS Results and Limits

FSP-CMS Meeting1-2 October 2012DESY Zeuthen

LHC Physics Discussion - 10/9/2012 2

GMSB and GGM Gauge-Mediated SUSY Breaking (GMSB) [ G. Giudice and R. Rattazzi, arXiv:hep-ph/9801271 ] = SUSY couples to normal matter through gauge interactions = Gravitino: LSP

General Gauge Mediation (GGM) [ P. Meade, N. Seiberg, D. Shih, arXiv:0801.3278 ] = neutralino NLSP a mixture of Bino, Wino and Higgsino = photon/Z+Gravitino or W+Gravitino final states -> one (or two) photon(s) + MET = focus on strong production: many jets

V. Sola

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GGM Phenomenology @ the LHC

V. Sola

Neutralino NLSP mixture of Bino, Wino and Higgsino Bino-like NLSP:

Wino-like (co-)NLSP:

Bino-Higgsino-like NLSP:

R-parity is conserved -> 2 LSPs per event ★ MET is defining signature

[ J. Ruderman, D. Shih, arXiv:1103.6083 ]

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GGM with One Photon at CMS

V. Sola

Final states with at least one photon γ + Jets + METIt includes the case ofBino-Higgsino-like NSLPγ + h + MET

Results presented in ICHEP 2012 ∫ L dt = 4.04 fb-1 2012 Data @ √s = 8 TeV [ CMS Collaboration, PAS-12-018; AN-2012-154 ]

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Trigger Efficiency

V. Sola

Analysis trigger: HLT_Photon70_CaloIdXL_PFHT400Baseline triggers: HLT_Photon50_CaloIdVL (prescale = 900) HLT_Photon75_CaloIdVL (prescale = 150) HLT_PFHT350 (prescale = 1000)

Trigger is fully efficient within an uncertainty of 4%

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Event Selection

V. Sola

Jets = particle flow jets, anti-kT (R=0.5), photon rejectedHT = scalar sum of pT of all jets with pT>40 GeV and |η|<3, no photon rejection

Photons ≥ 1ET > 80 GeVEiso

(∆R<0.3) < 6 GeV|η| < 1.442Jets ≥ 2pT > 30 GeV|η| < 2.6HT > 450 GeVMET > 100 GeV

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Standard Model Backgrounds

V. Sola

Fake photons -QCD (jets)

Fake photons –EWK (electrons)

Irreducible(photons)

γ + Jetj → γ

Dominant Background

Data - Driven

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QCD Background

V. Sola

Mis-measurement of MET in QCD processes-> direct di-photon, photon+jets, and multijet production with jets mimicking photons ✓ looser γ isolation requirements (γjet) orthogonal to signal selection ✓ pT spectra reweighted in low MET region (MET<100 GeV) ✓ systematic uncertainty of 10% assigned

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Standard Model Backgrounds

V. Sola

Fake photons -QCD (jets)

Fake photons –EWK (electrons)

Irreducible(photons)

γ + Jetj → γ

W, tope →γ

Dominant Background

Sub-dominantBackground

Data - Driven Data - Driven

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EWK Background

V. Sola

Events with true MET and an electron misidentified as a photon-> compare Z→ee events to Z→eγ to obtain e→γ fake rate

Ratio of signal used to estimate fake rate fe→γ

pT > 80 GeV: fe→γ = 0.011 ± 0.002 (stat) ± 0.001 (syst)Inclusive electron spectrum scaled by fe→γ to obtain EWK bkg

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Standard Model Backgrounds

V. Sola

Fake photons -QCD (jets)

Fake photons –EWK (electrons)

Irreducible(photons)

γ + Jetj → γ

W, tope →γ

ISR/FSRZ/W/top + γ

Dominant Background

Sub-dominantBackground

Sub-dominantBackground

Data - Driven Data - Driven Simulation

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Standard Model Backgrounds

V. Sola

MadGraph50% uncertainty

on the Xsec

Fake photons -QCD (jets)

Fake photons –EWK (electrons)

Irreducible(photons)

γ + Jetj → γ

W, tope →γ

ISR/FSRZ/W/top + γ

Dominant Background

Sub-dominantBackground

Sub-dominantBackground

Data - Driven Data - Driven Simulation

LHC Physics Discussion - 10/9/2012 13

Single Photon MET Spectrum

No excess observed over SM expectations

Six bins in MET > 100 GeV used to set limits [100, 120, 160, 200, 270, 350, ∞)

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Single Photon Event Display

V. Sola

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Limit Calculation

V. Sola

Systematic errors

= Uncertainty on trigger efficiency 4% = Theory errors: scale and PDF errors combined at each point and cross section varied by 1σ Limit calculation = CLS method with likelihood-ratio test statistics at 95% = full propagation of errors = GGM Signal Monte Carlo (grid scan) Prospino used for NLO cross section

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Interpretation: Bino-like NLSP

V. Sola

Bino-like GGM scanmχ0 = 375 GeV, msquark,gluino = 400-2000 GeV (step 80 GeV)sleptons and all gauginos except NLSP @ 3.5 TeV

γ + ≥2 jets + MET γ + ≥2 jets + MET

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Interpretation: Wino-like NLSP

V. Sola

Wino-like GGM scanmχ0 = 375 GeV, msquark,gluino = 400-2000 GeV (step 80 GeV)sleptons and all gauginos except NLSP @ 3.5 TeV

γ + ≥2 jets + MET γ + ≥2 jets + MET

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Updated MET Spectrum

V. Sola

Json: 27Aug ∫L dt = 9.4 fb-1

CMSSW: 532patch1

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Summary and Outlook

V. Sola

CMS analysis designed to cover a broad range of final state SUSY GMSB scenarios = Preliminary results with 4 fb-1 of 8 TeV data collected in 2012 = data-driven background estimate for QCD/EWK sources = no excesses seen over SM predictions

Exclusion limits set in bino- and wino-like neutralino NLSP = Bino like: msquark < 1.2 TeV, mgluino < 1.1 TeV excluded = Wino like: msquark < 900 GeV, mgluino < 800 GeV excluded

Results with full 2012 statistics foreseen in Moriond2013 = increased statistics = optimised analysis = b-tagging and angle variable investigation will be included