supersymmetry searches and its implications monoranjan guchait tifr, mumbai from strings to lhc iii...
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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