Hasty Overview of Photon + MET Studies in the Context of GMSB Bruce Schumm Joint SUSY/UED Meeting 23 November 2010

Significant Transition: MGM to GGM Tevatron analysis based on “Snowmass Points and Slopes” trajectory that is essentially Minimal Gauge Mediation (MGM) MGM ties strong (gluino) and EW (neutralino) partner scales together, and leads to very massive gluino  Tevatron analyses exploited weak production (lot of data at low energy); sets limits on neutralino mass MGM not particularly well motivated  look at Generalized Gauge Mediation (GGM) which decouples strong, EW scales Re-cast in terms of limits in M g -M  plane for each of three possible neutralino species: Bino-, Wino-, Higgsino-like

Production cross-section (7TeV) Bino - like Neutralino: |M1| <<  and |M1| < |M2|; M of Neultralino NLSP ~ M1, Neultralino NLSP   + Gravitino (76%) For Bino-like neutralino, two photons + MET is most promising but lose coverage if hadronic activity is required (jets, HT, etc.) No visible jet activity when M g ~ M  Thanks to Shih/Ruderman, ArXiv MGM trajectory

p T of photons M bino = 150 – 580 GeV M gluino = 600GeV (  = 0.26pb ) M bino = 200 GeV M gluino=400–700GeV (  =6–0.07 pb) BR doesn’t change ~ 80% p T of photons ~ similar BR changes vs. M bino: 90% (M bino = 150GeV) 65% (M bino = 580GeV) p T of photons!

P T neutralino M bino = 200 GeV M gluino = 400 – 700 GeV M bino = 150 – 580 GeV M gluino = 600GeV

Production cross-section (7TeV) Wino - like Neutralino: |M2|<<  and |M2| < |M1| Natural for photon+lepton channel Not shown: Higgsino, which has no photonic decay, but a partial admixture might show up in photon + jet(s)

Analysis Details (largely a list of items without specifics; see sharepoint(?)… not optimized yet since signal MC just becoming available) Trigger: EF_g10_loose period E2 and before EF_2g15_loose after period E2 Data streams: various (AOD, Susy D2PD, SUSY D3PD) SUSY Good-Run-List (GRL) Photon Defintion: RobustTight |  | < 2.37 and not in crack region Isolation: EtCone20/Et < 0.1(see next slide) Require two photons: E  1 > 30 GeV; E  2 > 20 GeV Overlap removal Jet cleaning, OTX, good primary vertex…

Real photons (signal, QCD direct-  ) Fake photons (jet  ) Photon Isolation Requirement Fairly strong preference for E T Cone/E T. Since jet  backgrounds not expected to dominate, choose loose cut E T Cone/E T < 0.1.

MET We will use RefFinal MET cut not yet chosen; typically would be ~100 GeV (or: use no MET cut?) SUSY “standard” is SimpRefFinal, but this contains no explicit photon term

BACKGROUNDS – ROUGH OUTLINE Basic Idea: Use control samples to constrain MET shapes of various background processes. Normalize to data in control regions. Backgrounds without instrinsic MET Two real photons: MET from Z  ee One photons, one jet  photon MET from tight/loose photon control sample Two jet  photon MET from loose/loose control sample? Fit region MET < 30 GeV (?) to normalize separate contributions

Composition of Photon-Loose Control Sample (Single photon)

Single-photon control sample: Data vs. MC We know there are K-factor uncertainties, but we can see that jet   fakes are not horribly out of whack. Next up: di-photon control sample

Backgrounds with intrinsic MET Assumption that this is dominated by e   fakes in W , ttbar, etc. MC suggests 85-90% of background is e   ; remainder is jet   Control sample is e  (veto if second  ) Have started with tight photon + medium electron, but are wondering if tight/tight is better (future triggers a consideration) Derive  fake content by applying e  rate measure via Z sample tag-and-probe Still need to separate out component with intrinsic MET from that (such as Z  e  ) without, since the Z  fakes will be accounted for in the no-MET control sample

GMSB1SPS8 BG (Z,W,Z ,W , ttbar) 0e2p1e1p1e1p(ex cl) 0e2p1e1p1e1p(ex cl) 0e2p1e1p1e1p(ex cl) All62 +/ / / EventE mFract > / / /- 715 Npho/ Nelec 29.0+/ / / / / / / / /- 94 Met > 50 GeV 23.4+/ / / / / / /- 477+/- 976+/-9 HT > 150 GeV 23.3+/ / / / / / /- 467+/-866+/-8 e  Control Sample Composition (helps to reject events with second hard photon)

Electroweak contribution to the e  control sample Dominated by Z at low MET Use to estimate background for MET about ~100 GeV Comparison of “signal” (two photons) to “control” (one electron/one photon; reject if second photon)

Systematics to Consider Event Selection Systematics Trigger (and skim if used) Photon identification and selection Et scale (Et cut) MET response (MET cut) Isolation cut (Model dependence) Object quality (OTX cut) Pileup effects Cross Section Uncertainties Parton distributions K Factors

More Systematics to Consider Background Systematics Control sample statistics - low MeT normalization of QCD background - e  sample - e   rate determination Relative amount of jet   vs. direct photon in QCD background Non e  backgrounds with intrinsic MET Luminosity Uncertainty

Additional needs/opportunities Photon efficiency from Z  ee? Limit formalism (fit to MET spectrum?) Trigger studies Strong ISR Other discriminating varilables (HT, , M , …) Non-pointing photons Wino/Higgsino-like analyses (single-photon + XXX?) Work on reducing e  rate (extra hits, B-layer outliers…) Other ideas…