Photon + MET Analysis Bruce Schumm UC Santa Cruz / SCIPP 05 August 2013 SUSY Review Talk

Prior Analysis: Diphoton + MET A: Strong production, heavy bino B: Strong production, light bino C: Electroweak production Strong production EW production For strong production, high total-energy cut gives ~background-free analysis

8 TeV Analysis: Diphoton + MET “SPS8” Trajectory For 2012 (8 TeV) Data: Augment “constrained” weak production SPS8 model with wino/bino grid Bino =  1 0 Wino = degenerate triplet  1  and  2 0 Production through  1   2 0 and  1 +  1 - Signal region optimization points Low-mass, high-mass bino for Strong and EW production Resulting signal regions “Model-independent” selection  MET cut for which QCD, EW background are about the same.

Note: Photon ET cut up to 75 GeV (was 50 for 7 TeV analysis)

Results unblinded Tuesday 30 July after sign-off on background- estimation results Three components to backgrounds: 1)Jet  photon fakes (“QCD background”); use loose-tight control sample 2)Electron  photon fakes (“EW background”); use orthogonal eγ control sample scaled by measured e  γ fake rate 3)“Irreducible” backgrounds with two real photons + MET; includes Wγγ and Zγγ production with neutrinos in W,Z decays

“QCD” Background Define “control” photon as ET > 50 GeV almost-tight photon that fails at least one of two identification requirements: Shower shape in shower core (“fracs1”) Shower width (“weta1”) Define four control samples based on control-photon isolation and presence of 0 or 1 additional tight-isolated (signal) photons QCDg: non-isolated control, 0 tight photons QCDg+iso: isolated control, 0 tight photons QCDtg: non-isolated control, 1 tight photon (nominal sample) QCDtg+iso: isolated control, 1 tight photon In “blind” region (MET < 100 GeV), QCDtg+iso is seen to be good proxy for tight-tight sample (but statistics not adequate for high-MET background estimates)

Ratio relative to QCDtg+iso; Red is nominal QCDtg Intermediate MET discrepancy between γγ (QCDtg+iso) and QCDtg source of much discussion… improves as MET grows… we’ll get back to this.

30 July QCD backgrounds: basis is ABCD method (this is for nominal “QCDtg-noiso” control sample D = A B C __ * ABCD D A B C

SP1 Extrapolation Statistics are limited: Look at estimate for series of relaxed M eff cuts and extrapolate to cut value (1500 GeV)  More precise estimate of QCD background SP1 M eff cut value To guide the eye

SP2 Extrapolation

SP1 and SP2 QCD Background Estimates SP1 Direct estimate: < 0.11 at 68% CL Extrapolation confirms this level  chosen as estimate; subsumes other uncertainty sources to be discussed next SP2 Direct estimate 0.33  0.33 (gaussian errors) Choose exponential extrapolation for central value Choose 1 Poisson (asymmetric) 1-sigma statistical range for upper uncertainty range  chosen for estimate; again subsumes other uncertainty sources

Issue for Photon(s) + MET Analyses: What MET? Significant changes for p1328 relative to p1181 Use gamma-gamma MC as proxy for signal (can look at high MET) EG10NoTauPhotonLoose designed for photon analyses; performs worse in p1328 “Vanilla” MetRefFinal does well

Control samples for MetRefFinal “g” is control photon (loose but not tight); can be isolated or not “t” is isolated tight photon “QCDtg” is nominal diphoton control sample  Good agreement w/ signal MET, especially QCDtg

Challenges: “Irreducible” W  Background Sizeable for EW production and “model independent” selections Constrain with data looking at (e, )  events Expected signal (MC) 50 < MET < < MET < 250 Expect: ~1.5 Observe: 0 Constrains K-factor (currently assumed to be 3  3)

CMS diphoton+MET with 4 fb -1 at 8 TeV CMS diphoton analysis: Employs no “overall energy scale” observable (H T, M eff ) Single analysis similar to ATLAS “MIS” signal region Look at strong production only

Single Photon + MET Analysis Motivation: Diphoton analysis may not be sensitive if Neutralino is not NLSP (no photons; not for this session!) Neutralino is the NLSP but is not purely bino GMSB Neutralino NLSP Phenomenology Bino-like  diphoton final state Wino-like admixture  photon + lepton Higgsino-like admixture,  <0  photon + bjets Higgsino-like admixture,  >0  photon + jets Single Photon + MET analysis covers this final, missing signature

CMS single-  analysis Photon E T > 80 GeV 2 jets with p T > 30 GeV H T > 450 GeV MET in bins, but sensitivity arises for MET > 250 Set limit of m gluino > 1125 GeV for bino- like neutralino (4 fb -1 at 8 TeV) Single-Photon + MET Signal Regions Minimize model dependence by minimizing N jet requirement RT2 is fraction of total visible energy in two leading jets

Photon + MET Challenges / Next Steps Devising grid was significant development (tune gluino, neutralino BFs and lifetimes) but is now being submitted for generation. Next steps: understand backgrounds challenges, e.g.

Conclusions and Outlook For 8 TeV data, significant new model space has been introduced Weak production (decoupled strong partners) limits with diphoton analysis (bino-like neutralino) GMSB scenario with photon + jet signature Plan is summary paper with all four photon(s) + MET analysis, covering full range of neutralino NLSP possibilities, plus electroweak production for bino- and wino-like NLSP Distinction between pointing, non-pointing signatures is somewhat arbitrary and artificial  Combine into unified analysis for 2015 data?