Download Zerwas_PASCOSMerida

Search for Higgs and Supersymmetry
PASCOS 2012
Merida
June 7, 2012
Dirk Zerwas
LAL Orsay
• Introduction
• Standard Model Higgs (low mass)
• Beyond the Standard Model Higgs
• Higgs couplings
• Supersymmetric particles
• Conclusions
The LHC
2011:
5.6fb-1
delivered,
4.6fb-1 to
4.9fb-1 for
analysis
Great
Startup
in 2012:
Gain
1TeV
4fb-1
2012:
conditions
becoming
more difficulty
but
manageable
2012: 3fb-1 for
ICHEP
The Standard Model Higgs at the LHC
• Signal dominated by gluon fusion
• VBF (qqH) next candidate
• VH smaller with large backgrounds
• ttH for higher energies
• exp: common analysis then separate gluon
fusion,VBF
• low mass: tau (but background)
• VH (difficult: only access to b)
• WW (leptonic): less mass info
• ZZ (leptonic): clean, low rate
• photons (rare, mass info)
NLO, NNLO, NNL QCD+NLO-EW, BR: Anastasiou, Dawson, Djouadi, Harlander, Kalinowski,
Kilgore, Melnikov, Spira, P. Zerwas and many more….
H ττ
• usually 1 hadronic tau
• transverse mass (W+misID-jet)
• tau mass via LL technique
• cat 1:VBF
• cat 2: boosted (1j > 150GeV)
• cat 3: 0/1 j >30GeV
• Z decays dominate (resolution)
VBF: Plehn, Rainwater, Zeppenfeld…
• VBF channel (2jets) as example
• better separation (recoil)
• MMC
• Z decays dominate
• 5x signal
• currently essentially inconclusive
W/Z+H W/Z+bb
• BDT used (jj, separation….)
• order 100-150GeV pT
• 2 b-tagged jets
• missing ET/Z-mass
• dominant BG: top, Z/Wbb
• similar approach
• order by V pT
• S/B 1% (lowest pT) - 10% (highest pT)
• BG normalization from data (sidebands)
boosted: Butterworth, Salam ….
H WW lνlν
Dittmaier, Dreiner…
• mass information: weak (neutrinos)
• Spin correlations (lepton acoplanarity)
• up to 2 jets
• separate by jet-multiplicity and flavour (e/μ)
• at least 20GeV proj ETmiss
• BDT used!
• WW dominates….
• no significant excess
Final yesterday
H WW lνlν
• good description of ETmiss necessary
• jet categories 0,1,2
• separated by flavor
• transverse mass final discriminant
• S/B order of 1/10
• compatible with bg only
• 1sigma (yesterday)
HZZ 4l
• good lepton ID down to low pT
• 7/5GeV (electron/muon)
• ZZ main background
• Z+jets secondary background
• clean channel
HZZ 4l
Excellent description of BG:
• on-shell Z ok (m12)
• off/on-shell Z ok
Low mass: width is
detector resolution
High mass: width is width
Hγγ
• vertex reco for mass resolution
• CMS: use of BDT based on the
reconstructed photons (higher sensitivity)
The complete picture
TeVatron: (W/Z)+H to b jets
• LEE!
• about 2 sigma
Supersymmetry
• fermion boson
• has “no” problems with radiative
corrections (quadrat. div.)
• has a light Higgs Boson (<140GeV)
• interesting pheno at the TeV scale
spin-0
squarks:
~ ,~
q
R qL
spin-1/2
spin-1
q
gluino: ~
g
g
sleptons:
~ ~
ℓR, ℓL
ℓ
h,H,A
neutralino
χi=1-4
Z, γ
H±
charginos:
χ±i=1-2
W±
3 (or more) neutral Higgs bosons: h, A, H
1 (or more) charged Higgs boson(s): H±
and supersymmetric particles
Many different models:
• MSSM (low scale many parameters)
• mSUGRA (high scale few parameters)
• DSS (SUSY with heavy scalars)
• GMSB
• AMB
Additional (s)particles:
• NMSSM
• MRSSM/N=1/N=2 hybrid
• and many more
Talk Pran Nath
V-Talk Pavel
R-parity
• production of SUSY particles in pairs
• (Cascade-) decays to the lightest SUSY particle
• LSP stable, neutral and weakly interacting:
neutralino (χ1)
• experimental signature: missing ET
Supersymmetry: neutral Higgs bosons
Higgs sector: mass of A, tanβ (vev ratio)
tanβ ↑: g(Hτ,b) ↑
D0:
• final states with τ and bbb
ATLAS and CMS:
• tau pair final states
• mA ↑ cross section ↓
• large exclusion with 4.6fb-1
SM-like h
mA up to 500GeV, tanβ down to 10
Supersymmetry: charged Higgs boson
Signature for m(H±) <m(top)
• top pair production
• increase decays of top to tau
• larger transverse mass
• no excess 
• exclude as function of BR
Interpretation in the MSSM:
Exclude down to 2%
Higgs couplings at the
SFitter (Lafaye, Plehn, Rauch, D.Z. and friends):
arXiv:1007.2645, arXiv:1205.2699,
LHC Contino,…
Define couplings as deviations from SM:
Restrict total width (LHC blindness):
• allow only tree-level deviations
• tree-level transported to loops
• no genuine deviations in loops
http://www.thphys.uni-heidelberg.de/~plehn/index.php?show=sfitter&visible=tools
Higgs couplings at the LHC
• near future couplings (if…)
• ultimate couplings (if…)
Higgs 125GeV and Supersymmetry
A. Djouadi et al.
hep-ph/1112.3028
• need to maximize the radiative corrections to
increase Higgs boson mass
• electroweak scale (3TeV: maximal mixing)
• mixing parameter
Large mixing, but no constraint on the stop mass:
Lindner (et al): 125GeV good for Standard Model up to GUT scale
Search for Supersymmetry: gluinos and squarks
Signature:
• colored particles  large (pb) cross sections
• many high transverse momentum jets
• large missing ET
Measure background from data (CRs)/
Extrapolate sensitive variable
• many cross checks possible
• no exciting deviations 
Equal squark and gluino masses: 1.4TeV
Search for Supersymmetry: 3rd generation
3rd generation:
• large mixing possible
• could be lightest squarks
• mSUGRA (cascade)
CMS:
• MSSM (direct)
• inclusive b-tagged analysis
ATLAS sbottom pair production:
• 2 b-tagged jets
• missing ET
Exclusion up to 400GeV
14TeV:
• sensitivity to 2.5TeV colored sparticles
Search for Supersymmetry: stops
New this month
Direct stop pair production:
• stop decay to chargino (100%)
• chargino (106GeV) W* decay
• 2lepton signature plus jets
• control regions for Z and top background
• exclusion zero-suppressed
• exclusion up to 140GeV (LSP: 45GeV)
Search for Supersymmetry: Electroweak Sector
Signature:
• associated production of charginos and neutralinos
• supersymmetric version of WZ (difficult)
• leptonic decays  3(and more) leptons (muons,e)
• missing ET
Example:
• Expect 26±5 Observe: 32 
MSSM limits:
• improve on LEP
difficult scenario: limits of order
300GeV obtained with increased
leptonic BRs (intermediate sleptons)
GMSB
Signature:
• 2 taus with jets and ETmiss
• effective mass
• transverse masses
Going beyond LEP significantly
Low tanβ region for 2lepton search
AMSB
Signature:
• long lifetime: chargino and LSP
degenerate winos
Talk D.P. Roy
• interaction with material
• bad tracks
Talk Manuel Gerardo Paucar Acosta for MSSM focus Point
Measure Supersymmetry
LHC:
• 5% level mass measurement
HL-LHC:
• improve to 1%
ILC:
• electroweak sector measurements
• precision 0.1%
SFitter: Lafaye, Plehn,
Rauch, D.Z. and friends
arXiv:1007.2190
arXiv:0709.3985
LHC:
• 12fold ambiguity
ILC:
• solves ambiguities
LHC
LHC:
• hint on Parameter unification
HL-LHC:
• increases precision
Dark matter (deduced):
LHC:
• % level with ambiguities
Talk Pran Nath
HL-LHC + ILC
Conclusions
• SM Higgs: more data is needed
• roughly >10% precision at LHC
• easy SUSY easily excluded
• difficult SUSY: +luminosity 14TeV-ε