Supersymmetry Searches and itsimplications

Monoranjan GuchaitTIFR, Mumbai

From Strings to LHC III 8-14th December, 2012 Puri

Outline

Introduction: SUSY

Results from LHC

Constraining SUSY models

Future

Outline

Introduction: SUSY

Results from LHC

Constraining SUSY models

Future

Apologies to, whose work is not referred/discussed

Why SUSY

Stabilization of Higgs Mass

Coupling unification

Dark Matter Neutrino Mass

The MSSM: particle content

Couplings are parameter space dependent

Play important roleIn collider searches

Discovery of Charged Higgs..an unambigoous signal for NP

Supersymmetry: A broken Symmetry

m(e) ≠ m(e)~

SUSY is not exact SUSY has to be broken

Soft Mass terms:

Origin of these mass terms are yet to be understood

100+ parameters

SUSY breakingSSB is done using MSSM fields:

Mass scale FMass scale M

Gravity mediation Gauge mediation

Anomaly mediation Gaugino mediation

Softmasses~ F/M ~ 1 TeV

Not supported by Expt!!.

mSUGRA/CMSSMSUSY breaking is mediated by Gravitational interactionBreaking scale ~1010 GeV

Model defined by:m0, m1/2, A 0, tanβ and sign(µ)

Low Energy masses and couplings spectrum FCNC natural

RG

EWSB is automatic

Mass Matrices

R

L

ff

ff

mX

Xm3rd Generation mass matrices

)cot/tan( fff AmX

)~,~,~( bt

Chargino mass matrices is a 2X2 mass matrices:

tan,,,2MNeutralino mass matrices is a 4X4 mass matrices:

tan,,, ,21 MM

21~,,~

~,

~ HW

04

03

02

01

02

01

~,~,~,,~,~,

~ HHZ

Mass Pattern

MSUGRA mGMSB

mAMSBPhenomenology is different

SUSY at the LHC

SUSY particle production at the LHCStrongly interacting particles, like squarks and gluinos are produced dominantly.

Gluinos and Squarks cascade through lighter particles. Signatures are very diverse.

Gluino+Gluino

stop+stop

M 1 TeV ̴�

σ 0.2-0.3 pb ̴�

8 TeV

SUSY signals in Colliders

g

02

~

~q1

Leptons+photons+jets+Missing energy,

∆m

∆m

Model Dependence

Model Dependence

At the LHC, gluinos and squarks are produced domminantly

W/Z

W/Z

Inclusive signalsGluino/Squark + Gaugino cascade

0 lepton + jets + METGluino/Squark + leptonic decay Gaugino/slepton

1 lepton + jets + MET2 leptons(SS/OS))+jets+MET

Gluino/Squark cascade in GMSB modelLepton(e,μ,τ) + jets + METphoton+MET

Rates production cross section X BR ̴�

Signal and Backgrounds

Cuts are used:)( jetspH TT METHM Teff

Missing transeverse energy(MET)

TpMHT → 2MT

+ b-tagging Razor

SM Bg cross sections are:(7 TeV)

Results from CMS and ATLAS

Squark and Gluino Searches

mSUGRA/CMSSM

2011 searches by CMS

CMS

M(gluino) > 1. TeVOtherwise, m(gluino) 820 ̴��GeV

Simplified Model Spectra(SMS)

T1tttt

SMS summary Plots

Exclusion limit: m(mother)-m(LSP)=0 and 200GeV

m(gluino) 1 TeV, excl ̴�

7 TeV, <4.98/fb

Chargino and Neutralino ProductionIf colored sparticles are very heavy, then looking for Gauginos is another way to find SUSY Productions are mediated bymostly quark and anti-quark Annihilation, pure EW interactions,Cross sections are expected to be low

M(chargino) 400 GeV, ̴� c.s 10 fb ̴�

Chargino- Neutralino Searches

3 leptons + MET, no jets

4 leptons + MET, no jets

03,21 ,

ZW ,,01

W/Z/slepton

Chargino and Neutralino: 3 lepton

tau enrich final states

Chargino, Neutralino, Slepton Searches: Summary

CMS

01

5.05.0

mmml

m(C1) m(N2) >650 GeV ̴�If M(LSP) GeV ̴�and BF(l+l-)=0.5

3 leptons, four leptons,two SS,OSSF,+2 jets, two non-resonant (OS)

SUSY particle production

Stop pair production

Stop pairs are produced via strong interaction

500 GeV stop mass 100 fb ̴�

21

~,~~

,~

ffff RL

Stop: SignalGluino mediated,

01~~~ ttttg

Direct Production

Many b jets in the final states,

Stop Search: Gluino mediated01

~ bbg 01

~ ttg

8 TeV, L=12.8/fb

gm~ 1.2 TeV GeVmb 6001

GeVmt 4001

ATLAS

Direct stop productionATLASjets, leptonic channels

Work in progress to increase sensitivity

Direct stop production at CMS

Direct Sbottom Production

0,5001

xb mGeVm GeVmGeVm xb 175,4001

Photons+METPhotons can be reconstructed and identified with high purity-> clean experimental signature Gauge mediation is one of the SUSY model where SUSY breaking Is transmitting SUSY breaking to MSSM Gravitino LSP G

~01

Biggest Bg: QCD jets fake as photon

Single photon+MET+jets

Di-photon

Constraining SUSY

Energy

Luminosity

Cosmic

Constraints on NPFlavour Physics

SM Value:

LHCb value:

910)38.053.3( 95.1

2.1 102.3)(

sBBr

Flavour PhysicsBs->s + gamma

44 1037.4)(1077.2 sbBr

Cosmic Connection:Dark Matter

SM cannot offer a Dark Matter candidate

Lightest Neutralino is a DM candidate

155.010 24 h

SUSY Higgs bounds

MA<140 GeV=> MH+< 160 GeVMA<200, tanβ<10MA>200, tanβ is large

Higgs Mass Discovery

ATLASCMS

GeVMGeV h 129123

Higgs Mass and 3rd GenerationAt the tree level, Higgs mass, 2cosZh mm

4

4

2

2

2

4

2

2

22

42

122

3ln

2

3

MS

X

M

X

v

m

m

M

v

mm t

S

tt

t

Sth

Loop level,

Higgs mass is sensitive to stop mass, maximized for maximal mixings: Accurate loop calculation is needed to determine stop massesfor 125 GeV Higgs.

Higgs in MSSM

Large top squark mixing leads to lower and more natural top squark mass

In maximal mixings Needs stop mass heavier than the current bound.

SuSpect and FeynHiggs has disagreement

Higgs mass and FTHeavy stop mass are required to boost Higgs mass to 125 GeV.

In SUSY theories,

Top-stops-Higgs loop,

Right hand side needs some tuning to achieve the correct scale of EWSB

Fine tuningThe amount of FT is determined by the size of the Higgs mass relative to the size of corrections to the quadratic term of potential.

The fine tuning parameter:

Fine Tuning

FT >100(200) for Xt <0(>0)

Λ=10 TeV

Stop mass can be as low as 500 GeV at maximal mixings

Hall, `11, Nomura ,`06..

FT: Spectrum

FT: Spectrum

Looking for 3rd generation squarks, also charginos and Neutralinos, an urgent need.

Constraining mSUGRA

mSUGRA: Constraining

)sgn(,tan, ,0,2/10 Amm

Sensitive SM parameters: ewsbt mm ,,,

)(

)())(|()|(

dp

dpdp

Bayes theorem,

Experiment

Observables

SUSYKIT, Multinest, SOFTsusy, Micromega SuperBayes. Eliis et. al ’11,’12

Ghosh,MG,Raychaudhuri,Sengupta,’12

P.Nath et al. 1207.1839

Prediction Gluino-Squark Mass

Best Fit point: TeVmTeVm qg 5.6,8,3 ~~

MA-tanβ

Decoupling Limit, (MA>>MZ) is favoured

Stop-stau mass

μ-gluino mass

Summary for mSUGRA

Gluino mass > 690 GeV, M(squark)>1.5 TeV,

M(chargino)>95 Gev, m(slepron)>580 GeV

M(stop)>580 GeV, m(stau)>310GeV

M(Heavy Higgses)>540 GeV

P.Nath et al. 1207.1839

Constraining pMSSM

Constraining pMSSM

o All soft masses are real o Sfermion mass matrices and trilinear couplinsg are all diagonal i.e no flavor changing at tree level. o soft SUSY breaking and tri-linear couplings of the first and second sfermions generations are the same at the EW scale. 22 parameters.

pMSSM

Constraints: pMSSM

95.12.1 102.3)(

sBBr Xenon100 +others

XXSMXX RHH )(/)(

SMXX XXhBrXXhBrR )(/)(

Mahmoudi, et .al 1211.4004

pMSSM: MA-tanβ

MA > 400 GeV is preferred, decoupling regimes for all tanβ

pMSSM:Lighter Stop mass cot tt AX

St MX 6Strong mixing are required for 126±3 GeV Higgs.

Top squark mixing parameter

pMSSM: Sbottom

Low sbottom mass with a moderate mixingis preferred.Di-photon rate is increased.

Sbottom mixing parameter: tan bb AX

pMSSM: Stau

Low values of stau mass100-200 GeV, is preferred,di-photon rate is enhanced, Large values of stau mass, is preferred for large Values of Rbb, via ∆b

tanAXstau mixing parameter

pMSSM: EW sector

For M1 and M2, the trend is due to the ∆b

where the contributions are tan2M tan1M:Wino :Bino

Higgs Mass and Dark Matter

Higgs Mass and Dark MaterSpin independent cross sections depend sensitively on the Higgs mass:

WMAPh

hR

)( 2

2

Bulk of the allowed regionLie in between XENON100 andXENON-1T and SuperCDMS P.Nath et al. 1207.1839

Higgs as a PortalHiggs boson may connect the SM to other “sectors”

SMSU(3)X SU(2)XU(1) Quarks+leptons

Higgs sector Hidden sector

Higgs couple with non SM particlesHiggs decays in invisible channel

h

Constraining Invisible width

Br(h→f) = (1 – Brinv ) BrSM(h→f)

Still room for a sizable Invisible BR < 0.4 at 95% CL

No effect in cross sections

Despite a suggestive hints in the data for Higgs like scalar, invisible Br remains essentially unconstrained.

Espinosa, Grojean, Muhlleitner, Trott,1202.3697,1205.6790

Prospects at the LHC

H→ invisible

Detail Signal and BackgroundAnalysis is performed for 8 and 14 TeV.

VBF: 2 jets +MET

ZH: Z→l+l-, bb, H→MET;

Ghosh, Godbole, MG, Mohan,Sengupta, ‘12

Prospects at the LHC

VBF: 2 jets +MET

Inv Br>0.80, for L=20/30/fb for 8 TeV >0.25 for L=300/fb for 14 Tev.

ZH: Z→l+l-, bb, H→MET;

Di-lepton mode̴�3.5σ sensitivity expected for 8 TeV and L=20/fb ̴� 5σ for 14 TeV and L=100/fb bb mode is not that promising, even using substructure method

Ghosh, Godbole, MG, Mohan,Sengupta, ‘12

Squark and Gluino Searches:Future prospects

8 TeV

Chatterjee, Sengupta, MG,’12More on D.Sengupta’s talk.

Event Shape Analysis

Prospects at LHC14

Baer et. al 1207.4846

qg mm ~~ ̴� 3 TeV

qg mm ~~ ̴� 1.8 TeV

14 TeV, L=300/fb

14 TeV, L=300/fb

LHC14 Discovery Potential

Baer et. al 1207.4846

Very likely LHC will run at 13 TeV

Top squark:Future A)

B)

C)

∆m plays a major role for detection

Phenomenology depends on the mass difference200—300 GeV masses, ∆m is not so large. and also less avaiilbility of parameter space in mSUGRA

Ghosh, Sengupta, MG, Godbole in progresss

Very difficult to find stop at the 8 TeV LHC in mSUGRA framework.

SummaryLHC is cornering SUSY, Gluino and squarks towards large values, needs very high energy and luminosity

Discovery of lighter stops may be channel to find SUSY, as well charginos and NeutralinosBut need favourable masses.Hope to listen some new results at the end of 2012

Precise measurements of Higgs properties may give us some hints.

Variation of SUSY, like NMSSM, NUHM, NUGM…..are not discussed,,.

Courtesy: H. MuryamaBefore..

Courtesy: H. MuryamaNow...

Thank you

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Gluino mediated: Summary