Inclusive susy reach of cms during early lhc running in the jets met n leptons topology
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Inclusive SUSY Reach of CMS during Early LHC Running in the Jets + MET + N Leptons topology. Bobby Scurlock Darin Acosta Richard Cavanaugh. University of Florida. Overview. Motivation Phase 1 : Prelude Establish “full-chain” Verify CMS Note 98-073 with “full-chain”

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Inclusive SUSY Reach of CMS during Early LHC Running in the Jets + MET + N Leptons topology

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Inclusive susy reach of cms during early lhc running in the jets met n leptons topology

Inclusive SUSY Reach of CMS during Early LHC Running in the Jets + MET + N Leptons topology

Bobby Scurlock

Darin Acosta

Richard Cavanaugh

University of Florida


Overview

Overview

  • Motivation

  • Phase 1 : Prelude

    • Establish “full-chain”

    • Verify CMS Note 98-073 with “full-chain”

  • Phase 2 : Main emphasis

    • Study systematic effects on reach

    • Establish reach scenarios

  • Phase 3

    • Write contributions for Physics TDR

    • Defend PhD !


Our interest

Our Interest

  • Extend earlier Florida JetMET BSM analysis efforts from CDF to CMS

  • Collaborate with other CMS members:

    • Florida Colleagues on SS 2μ Inclusive SUSY Reach Analysis:

      • A.Drozdetski, Y.Pakhotin, P.Bartalini, D.Acosta, G.Mitselmakher

    • JetMET Group:

      • Haifeng Pi, Arno Heister, Rob Harris, et al.

    • UF SUSY/BSM Theorists:

      • P. Ramond, R. Field, and K. Matchev

  • Focus on early (~10 fb-1) LHC physics

    • Establish realistic reach expectations

      • Study systematic effects

      • Consider “What if…” scenarios

    • Probe quasi-model-independent reaches


Earlier cms work

Earlier CMS Work

Abdullin & Charles (CMS Note 98-073)

  • Used Fast Sim. (CMSJET) of CMS detector

  • Established reasonable criteria for signal selection & background rejection, and sensible expectations for signal & background distributions

  • Studied some simple systematics

    • Signal & Background variations

    • Pile-up effects

  • QCD background was (remains) a serious challenge

  • DAQ TDR

    Gives idea of Level-1 Trigger and HLT requirements for good efficiency for SUSY events over several representative points in mSUGRA space


What if

What if…

…we assume a well understood detector?

  • 0 leptons + Jets + MET has most significant reach

…we assume, e.g., that calorimeter responses are not well understood?

  • Would n muons + Jets + MET be more significant?

  • If so, at what level of jet energy scale uncertainty?

Abdullin & Charles

(CMS Note 98-073)


Phase 1 analysis set up

Establish “full-chain” analysis

CMKIN 3+

OSCAR 3+

ORCA 8+

Develop RootMaker

Defining our own currently

Investigating JetMET ntuple

Run on Digis (baseline)

Run on DSTs (when stable)

“Full-chain” important for systematic studies !

Modify physics process

Perturb detector response

Change reconstruction

RecCollections

minbias

DST

Digis,Assocs

Stream

signal

Phase 1 : Analysis set-up

OSCAR

CMKIN

Simulation

Generation

MCinfo,G4 Vtx, Tk

SimHits

HEPEVTNtuple

MC generator

Production

ORCA

Analysis or Calibration

Reconstruction

Digitization

RecReader

SimReader

RecReader

Histo/Tree

Histo/Tree

RecColl, Digis

Histo/Tree

Digis

Histo/Tree

RecColl, Digis

User

Production

RootMaker

Tree


Phase 1 digi datasets signal

Phase 1 : Digi Datasets - Signal

Need more signal !


Phase 1 digi datasets ew background

Phase-1 : Digi Datasets – EW Background

Z+jets lagging a bit !


Phase 1 digi datasets qcd background

Phase-1 : Digi Datasets – QCD Background

Need inclusive TTbar !

Need more high PT QCD !


Phase 1 digi datasets higher order ew background

Phase 1 : Digi Datasets - Higher order EW Background

Location of inclusive

WW, ZW ?


Phase 1 confirm abdullin charles

Phase 1 : Confirm Abdullin & Charles

  • Examine distributions after full simulation:

    • Jet multiplicity, ET, ETMiss, Δφ(ETjet1, ETMiss), etc…

  • Simple optimised cut set based on significance = Ns / √(Ns+Nb)

    • Try/use initial selection criteria from Abdullin & Charles

  • Produce preliminary expected reach in m0 vs m1/2 plane

    • 10 fb-1

    • 100 fb-1

  • Ultimately, would like to limit number of cut sets used, by carving out regions in mSUGRA space rather than optimizing cuts for each particular point – this reduces systematics…


Phase 2 systematics the main emphasis of this work

N = (εSσS + εBσB) L

Estimate uncertainties in cross-section σB

Treat QCD differently from EW

K-Factors

Guess at uncertainties in Luminosity L

Estimate uncertainties in efficiencies εS , εB

MC statistics

Detector Effects

Reconstruction Effects

JetMET

Muon

Electron

Theory

Examine uncertainties on backgrounds in control regions

Phase 2 : Systematics: The main emphasis of this work


Phase 2 systematics triggers

Phase 2 : Systematics – Triggers

  • Jet Corrections at L1?

  • Trigger Efficiencies:

    • Jet+ETMiss

    • Muons

    • Electrons

    • Inclusive SUSY


Phase 2 systematics reconstruction of physics objects

Phase 2 : Systematics – Reconstruction of Physics Objects

  • Jets:

    • E/HCAL Calibration

    • Tracking Uncertainties

    • ET vs. h

  • ETMiss:

    • Calibration

    • Fake Rates

    • Azimuthal Isolation

  • Muons

    • B-Field

    • Detector Alignment

    • Brem

  • Electrons

    • B-Field

    • ECAL Calibration

    • Brem


Phase 2 significance estimator

Phase 2 : Significance Estimator

  • Estimate reach at 95% CL using likelihood

  • Include systematic effects via convolution

Likelihood for SUSY Signal hypothesis, given Experimental Data and assuming knowledge of Standard Model Background

Systematic Gaussian PDFs

Statistical Poisson PDF


Phase 2 quasi model independent studies

Phase 2 : Quasi-model-independent studies

  • “What if…” mSUGRA is not the SUSY breaking model realised in Nature?

  • Investigate more model independent approaches for setting reaches

    • Physical squark and gluino masses

    • Cross-section x BRs

    • Validate against several different SUSY models at generator level


Phase 2 famos

Potentially very useful for:

mSUGRA parameter sweeps

Estimates of systematic effects which are otherwise to costly

Investigate Distributions of Physics Objects:

JetMET:

ET of leading jet, ET of next leading jet, MET of event, Jet multiplicity, etc…

Muons:

PT of leading muon, PT of next leading muon, Muon isolation, etc…

Electron:

ET of leading electron, ET of next leading electron, Electron isolation, etc...

Phase 2 : FAMOS


Synergy with inclusive ss 2 susy reach

Synergy with Inclusive SS 2μ SUSY Reach

  • Authors:

    • Alexei Drozdetski (see today’s talk), Yuriy Pakhotin, Paolo Bartalini, Darin Acosta, Guenakh Mitselmakher

  • Many systematics are the same (or similar) for both analyses

    • Division of labor

    • Agree on a common Root Tree

  • Etc…


Conclusions

Conclusions

  • Interested in conducting inclusive SUSY search in the Jets + MET + Leptons topology to establish realistic reach expectations

  • In process of mastering analysis chain and crating analysis tools

  • Will conduct sanity checks against previous studies

  • Consider various “What if …” scenarios, and systematic effects

  • Would like to evolve to a model independent study


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