Teoretyczne podstawy informatyki

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Physics Program of the experiments at Large
HadronCollider
Lecture 5
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Outline of this lecture
Physics programme ? Higgs boson in SM and
MSSM model
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Theoretical basics
Fermions
Symmetries
Bosons, Interactions
Three families, with leptons and quarks
1) Poincaré Group 2) Gauge Symmetries
U(1)Y SU(2)L SU(3)c
? QED, g Z, W? Weak, g (electroweak
unification) 8 gluons QCD, gs
?eL eL
?? ?
?? ?
, ?R, eR,
c s
t b
uL dL
, uR, dR.
Only known solution the Higgs Mechanism
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Theoretical basics
Matter interacts with the quantum fluctuations of
the vacuum as well as with the vacuum itself

m2 /v
Empty vacuum
W,Z
mf/v
Ad hoc coupling
(Our vacuum)
-?v4/24
Self-interaction via V(?)
All couplings predicted
m2 /v
(unknown)
H
m2 ?v2/3
Mass unknown
??m2 /v2
H
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Theoretical basics are there bounds on mH?
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Higgs Introduction
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Higgs Present status of knowledge
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Higgs production at hadron colliders
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Higgs boson branching fractions
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How can one claim a discovery?
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Maximising significance
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H ? ??
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Simulated H ? ??
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H ? ????backgrounds
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H ? ????irreducible backgrounds
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H ? ????expected performance
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As example LAr electromagnetic calorimeter
H??? needs mass resolution 1
e.m. calorimeter energy
response uniformity 0.7
over ? lt 2.5
H ? ??
EM LAr Endcap
EM LAr Barrel
Had. endcap
Forward calo
135
120
105
Tile Calorimeter
m??(GeV)
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EM Endcap Construction requirements
e
End-cap wheel in vertical position (24/6/03)
?2.2 mm
? 9 ?m

• Thickness of 1536 plates for EM endcap

measured with ultrasounds during construction
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EM Barrel 1999-2002 test beam
S1
Fe
S3
,4
Pb
H8 beam line
BC1
BC2
BC3
BC4
muon counter
pion counter

• Test of 4(out of 32) barrel, 3(out of 16)
  end-cap final modules

• Required uniformity in regions of size ?? x ??
  0.2 x 0.4 0.5

(440 regions in the full ECAL)
Barrel module scan with high E electrons
?46
?15
?0
?0
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Toward Physics 2004 ATLAS Combined Test Beam
O(1) of ATLAS tested on CERN H8 beam line

• final detector

modules

• final electronics 

monitoring

• ATLAS software

to analyze data.
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Toward Physics 2004 ATLAS Combined Test Beam
beam

• 90 millions events collected( 4.5 TB)

• e, ?, ?, ? _at_ various energies, B0?1.4 T

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CTB electron studies(preliminary results)
Linearity
9 GeV beam energy pb?
E/Ebeam
points well within 1
100
200
Uniformity 0.5
Ecell(GeV)
constant term0.7
Electronics calibration pb
E(GeV)

• Work in progress to understand the material in
  the beam line

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H ? ZZ()? llll
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Simulated H ? ZZ()? llll
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Simulated H ? ZZ()? llll
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H ? ZZ()? llll control of reducible background
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H ? ZZ()? llll analysis
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Vector boson fusion
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Forward jet tagging
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Example qqH ?qqWW ?qql?l?
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Overall SM Higgs discovery potential
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Overall SM Higgs discovery potential
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Determination of Higgs boson parameters
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Higgs mass determination
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Higgs width determination
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Determination of couplings
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Determination of couplings
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Measurement of partial widths ratios
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Higgs pair production and self couplings
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MSSM Higgs sector
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Production cross-section
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Higgs decays
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h ? ??, bb
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A/H ? ??
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A/H ? ?? mass reconstruction
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A/H ? ?? lepton-hadron analysis
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A/H ? ??
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Charged Higgs
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Summary 30fb-1
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LHC discovery potential for SUSY Higgs bosons
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What can we do in one year?
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Conclusions