퐵푢푔푟푎 푌푖푙푑푖푧∗

Supersymmetry Content

 Introduction (SUSY)  Motivation (SUSY)  Stop Squark  Analysis  Samples  Cuts  Histograms  Conclusion

6 July 2015 Bugra Yildiz 2 Introduction

 SUSY is a proposed type of spacetime symmetry that relates and .  Each from one group is associated with a particle from the other, known as its , the spin of which differs by a half-integer.  If exists then it must be a spontaneously broken symmetry.

6 July 2015 Bugra Yildiz 3 Motivation

There are three principal motivations

 Naturalness : Radiative corrections are quadratically divergent in the ().

6 July 2015 Bugra Yildiz 4  Gauge coupling unifications : If the of the Standard Model are near the TeV scale, then measured gauge couplings of the three gauge groups unify at high energies.

 Dark : If R-parity is preserved, then the lightest superparticle (LSP) of the MSSM is stable and is a Weakly interacting massive particle (WIMP).

6 July 2015 Bugra Yildiz 5 Stop

 Stop squark is the superpartner of the top .

 It is a spin-0 (scalar).

 The is the heaviest known quark, the stop squark is actually often the lightest squark in many supersymmetry models.

6 July 2015 Bugra Yildiz 6  The stop is a key ingredient of a wide range of SUSY models that address the hierarchy problem of the Standard Model (SM) in a natural way.It would stabilize the mass against quadratically divergent quantum corrections, provided its mass is close to the electroweak symmetry breaking energy scale (246 GeV).  If this was the case then the stop would be accessible at the Large Collider.

6 July 2015 Bugra Yildiz 7  Depending on the specific details of the SUSY model and the mass hierarchy of the sparticles, the stop might decay into a and a , with a subsequent decay of the chargino into the lightest .

Bottom Quark

Neutrino

Stop

Neutrolino

Chargino

6 July 2015 Bugra Yildiz 8 Analysis

 Aim : We have to synchronize ourselves with single lepton stop analysis group.

 Software : CMGTools

 Samples : EOS /store/cmst3/group/susy/Phys14_V3/

6 July 2015 Bugra Yildiz 9  Sample Used : T1tttt_HL_1500_100

4 Top Quark

Gluino Mass : 1500 GeV Neutralino Mass : 100 GeV

High Mass wrt Low Neutralino Mass

6 July 2015 Bugra Yildiz 10 Cuts

0. No Cuts 1. 1 Lepton Cut 2. Lepton Veto 3. Njets ≥ 2 4. Njets ≥ 4 5. Leading jets pT > 80 unused 6. HT > 750 7. MET > 80 8. NbJet ≥ 1

6 July 2015 Bugra Yildiz 11 Cut Flow

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• I analyzed T1tttt_HL_1500_100 sample, applied the different cuts and checked the results. (https://twiki.cern.ch/twiki/bin/viewauth/CMS/ ACDSUSYSingleLepton) • Preparation for 13 TeV stop 1l analysis is continiue. (https://twiki.cern.ch/twiki/bin/view/CMS/Stop SingleLepton2015#Common_Baby_Format)

6 July 2015 Bugra Yildiz 31 Thanks

∗ This work has been supported by Hacettepe University, Scientific Research Projects Program through the Project: 014 A602 004-824.

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