1 Hamburg SUSY search strategies, Sergei Bobrovskyi, Ulla Gebert, Kolja Kaschube, Gordon Kaussen, Benedikt Mura, Friederike Nowak, Christian Sander, Hannes Schettler, Peter Schleper, Matthias Schroeder, Torben Schum, Jan Thomsen Universität Hamburg Early Analyses SUSY Model and Parameter Determination
Outline Early Analyses Release validation All-hadronic analysis QCD background estimation methods Optimize selection, estimate reach Leptonic analyses Cross cleaning, e.g. removal of electron-jet overlap Determination of SUSY Model and its Parameters Local fits, Likelihoods, i.e. event-by-event Global fits 2
Release Validation 3 Christian Sander, C.A. Ensure MC is simulated correctly Check RelVal background & signal Ensure Data is reconstructed correctly Online monitoring Fast offline analysis to track down problems Example: Is Simulation bug still present in 2.1.X? http://indico.cern.ch/conferencedisplay.py?confid=42240 phi dependent noise?
All-hadronic analysis PTDR2 plot, reach for 10 TeV is reduced Reach vs luminosity 4 Torben Schum, Benedikt Mura Christian Sander, C.A. Ratio parton luminosities 10 TeV/14TeV Sterling J.J.Sterling The inclusive searches have the best reach for SUSY With ~10 pb-1 reach can be beyond Tevatron limits If squark and gluino masses are below ~1 TeV SUSY can be discovered with ~1 fb-1
QCD: ABCD -method (1/3) 5 Torben Schum Extended method: Need not to be entirely uncorrelated! Determine the correlation of NB/NA w.r.t. one variable Fit this ratio in control-region Extrapolate to signal-region, and correct NC accordingly Extra
Linear Extrapolation, Δφhemisphere MET Torben Schum 6
QCD: ABCD -method (3/3) Torben Schum 7 Studied so far four variables (MET, Δφmin, Δφhemisphere, ηjet) in different pairings If the shape of at least one pair in the data, is as simulated, then QCD can be predicted in the all-hadronic channel
QCD Antenna 8 Sergei Bobrovskyi The QCD cross section has a factor which is a sum over all pairs of external lines color-weighted sum of radiation functions (antenna pattern) n: multiplicity Promising QCD sensitive variable, uncorrelated to MET. Some similarity to Event-shape variables (Sphericity)
QCD: Smearing -method 9 Torben Schum, Benedikt Mura, Christian Sander, C.A. 1. From data events: jet 2 MET ν or σjet smearing pt pt MET f pt =1 function: pt MET 2 smearing function jet 1 Either from data or MC-truth (ν pt) 2. Create new QCD sample Need high statistic of QCD events with low MET Smear jet energies, recalculate MET Normalize sample, e.g. using the ABCD method
Cross-cleaning 1/2 10 Benedikt Mura, Friederike Nowak,, C.A. Goal: implement event cleaning required by analyses, add and study at PAT-layer 2 remove/correct duplication across collections of Physics objects Implemented as a generic PatCrossCleaner, but should work on AOD objects, too. takes all input collections (muons, electrons, photons, jets, taus) calls individual cleaners at the moment: electron/jets, muons/jets, photons/jets resolves conflicts (ignore duplication with removed object) produces cleaned and dropped collections Reference: http://cmssw.cvs.cern.ch/cgi-bin/cmssw.cgi/usercode/bmura/patdev/physicstools/patcrosscleaner/ CMS Note in preparation
Cross-cleaning 2/2 Example: SusyAnalyzer like electron-jet Electron cleaning algorithm 11 Benedikt Mura, Friederike Nowak Jet Eshared > 0 Isolated Electron Eshared > 0.7*EJet Eshared < 0.7*EJet Remove jet Modify jet by - Eshared Non-Isolated Electron Remove Electron Modify jet by EElectron - Eshared Most matched electrons are isolated Cut on isolation effects determines final efficiency For parton matched electrons Eshared/Ejet is close to one See todays SUSY meeting for more details!
Kinematic fits 12 Hannes Schettler SUSY cross section is dominated by squark and gluino pair-/associated production Neutralino momenta unknown quark jet association unknown SUSY-Masses unknown (partly?) Fitting events with 7 jets to gluino-squark cascade Generator-level Reco-level Event-hypothesis with best χ² SUSY-masses except the one under study are assumed to be known, here m(neutralino 1) [GeV] m(gluino) [GeV] m(squark) [GeV]
Global Fits q~~ g 7 jets + ~~ χχ 13 Benedikt Mura Constraints Global parameters: SUSY masses
Conclusion 14 HH participates strongly in hadronic SUSY workgroup QCD background estimation methods MET validation JES Calibration Developing cross-cleaning algorithms, e.g. electron-jet Plan to expand analyses to electron final state Overlap with top or other german SUSY groups? Developing kinematic and global fits to measure SUSY Experience with Alignment (MillePede) Calorimeter calibration with global fit MET
Backup 15
msugra plane: Reach & x-section 16
Search strategies Large variety of BSM-theories Large variety of Search strategies: this talk Signature SUSY Scenario All-hadronic msugra, AMSB, split-susy,... msugra, UED, AMSB, splitsusy, LSCP, RPV, little Higgs jets + 1 lepton... jets + 2 lepton msugra, AMSB, GMSB ττ GMSB, large tanβ γγ GMSB 17
Putting it all together: Hadronic Analysis 1. Perform the Analysis t a 18
All-hadronic analysis in PAT 19