SUSY Discovery at 10 TeV?

UCL Atlas Meeting 2nd May 2008

Introduction 10 TeV run coming soon (3-4 months long? Could get 100 pb-

1?)

Our low-jet-multiplicity SUSY studies have potential for early data

- so what about at 10TeV… could we hope to see something? Currently no Monte Carlo…… BUT can reweight existing 14TeV MC

' 2 ' 21 1 2 2

2 21 1 2 2

PDF(x ,Q ,f )×PDF(x ,Q ,f )Weight =

PDF(x ,Q ,f )×PDF(x ,Q ,f )

2 21 1 2 2= (s,t,u)×PDF(x ,Q ,f )×PDF(x ,Q ,f )dxˆˆ ˆˆ

For particular configuration with s,t,u should just need to change the probablity that incoming partons had that configuration i.e. just a PDF reweight

xi : x of parton i at 14TeVx i’: x of parton i at 10TeV

Check of MethodExample Check: SU3 SUSY events generated in ATLFAST

pretty good agreement!

weights all < 1

Red is the reweighted sample

Event SelectionCSC5 2-/3-Jet+0lepton+MET SUSY analyses:

Cut No. 2-Jet 3-Jet

0 J70-XE70 trigger J70_XE70 trigger

1 pTJet,1 > 150 GeV pT

Jet,1 > 150 GeV

2 pTJet,2 > 100 GeV pT

Jet,3 > 100 GeV

3 MET>max(100,0.3*Meff)

MET>max(100,0.25*Me

ff)

4 |phi(Jet1,2)-phi(MET)| > 0.2

|phi(Jet1,2,3)-phi(MET)| > 0.2

5 no isolated lepton no isolated leptonFor simplicity, just use our CSC5-style 2- and 3-Jet analyses – full details in noteEffective Mass: Meff = ∑ pT

Jet,i + MET (sum runs over 2(3) highest-pT jets)

Results: 2-Jet+0-lepton+METCSC5 analysis: 14 TeV, 100pb-1

s = 14 TeV

REWEIGHTED to: 10 TeV

SUSY signal (SU3) reduced by factor of ~ 2.9

SM background reduced by factor of ~ 2.3

s = 14 TeV

s = 10 TeV

Results: 2-Jet+0-lepton+METCSC5 analysis: 14 TeV, 100pb-1

Compared to 14 TeV

REWEIGHTED to: 10 TeV

a few other mSUGRA points

s = 14 TeV

s = 10 TeV

Results: 2-Jet+0-lepton+METCSC5 analysis: 14 TeV, 100pb-1

14TeV 10TeV

SU1 23 12SU2 < 1 < 1SU3 39 22SU4 106 67SU6 16 8SU8 24 12

BackUps

REWEIGHTED to: 10 TeVCSC5 analysis: 14 TeV, 100pb-1

Results: 3-Jet+0-lepton+MET

s = 14 TeV

s = 10 TeV

REWEIGHTED to: 10 TeVCSC5 analysis: 14 TeV, 100pb-1

Results: 3-Jet+0-lepton+MET

s = 14 TeV

s = 10 TeV

14TeV 10TeV

SU1 11

SU2 < 1 < 1SU3

SU4

SU6

SU8