ATLAS and CMS activities

1
ATLAS and CMS activities

• Albert De Roeck
• CERN

ECFA/DESY meeting St Malo 12-15
April 2002
2
LHC Prospects

• New date for first beams/collisions 1/4/2007
• Initial physics run starts in 2007 ?? 10 fb-1
  (2.1033cm-2 s-1)
• Depending on the evolution 200-300 fb-1 in 5-6
  years
• (3.4-10.1033cm-2 s-1 )
• Studies ongoing for 1.1035cm-2 s-1 (SLHC)
• Needs changes in machine and detectors
• ?? 3000 fb-1 in 3-4 years, i.e. by the end of
  2010 or so
• CMS ATLAS preparing for first beam in 2007
• Concentrate on hard software
• Main questions are on trigger/DAQ, using gold
  plated physics channels
• Exploring of new physics studies not main
  activity now
• Discovery potential has been demonstrated
  for key processes
• Planned/existing physics review studies
• ATLAS physics TDR exist since 2000, may be redone
  in 2005
• CMS physics TDR planned for 2005, starting to
  prepare during 2002

3
ATLAS and CMS Plans

• Common LC/LHC studies
• There is interest but not yet much activity (5-10
  people/exp for now)
• We need to start with a fewspecific
  questions/studies
• (Agree on luminosities etc.)
• ATLAS Global fits using masses of measured
  particles, to scan
• and constrain the susy space ? Expect gain
  due to sleptons on M0
• Add branching ratio cross section
  measurements
• Will be initially based on the old LHC
  benchmark points
• CMS interest to start such activity/using
  new benchmark points
• ATLAS CMS check on gain of precise
  measurements of ?01 (and other gauginos) for
  reconstructing squark masses (mass splitting)
• CMS Combining heavy higgs (LHC) with light higgs
  (LC) measurement

4
ATLAS and CMS Plans

• Benchmark points
• ATLAS so far study of point E() (SPS 2()),
  maybe B (SPS 1a) next
• CMS point B, C (SPS 3) , E and G for trigger
  studies and reconstruction points I,L (SPS 4) for
  heavy Higgs to Tau
• (? point I could be replaced by SPS1b )
• SLHC study points M, K, H used (no SPS
  equivalent)
• Non-mSUGRA models take SPS selected points
• CMS Combined studies of extra dimensions ?
• Plan for first results
  end of June
• In the following
• A reminder of LHC reach, relevant for this group
• New studies in CMS, e.g. on susy mass
  reconstruction

() BDEGMOPW points () Snowmass points
slopes
5
Example LSP from LC
Impact of the precise knowledge of the LSP from
the LC on the neutralino two and
slepton masses
LSP mass
LSP mass
6
CMS
Visiting IP5 CMS getting into shape
7
Example The CMS experiment

• Tracking
• Silicon pixels
• Silicon strips
• Calorimeters
• PbW04 crystals
• for Electro-magn.
• Scintillator/copper
• for hadronic part
• 4T solenoid
• Instrumented iron
• for muon detection
• Jet Energy scale
• to 1.0
• EM energy scale
• to 0.1
• Luminosity
• to better than 5

8
Expected Event rates
Huge event rates The LHC will be a W-factory,
a Z-factory, a top factory, a Higgs factory etc..
9
SM Higgs search
Production and decay modes
10
Expected Results for the Higgs
- Will discover the Higgs in the range 100 GeV ?
1 TeV (if exists) - Precision on the measurement
of the mass between 0.1-1
11
H ? ZZ() ? 4 leptons

• clean signal, mass resolution 1
• precision on muon momentum comes from combining
  muon chamber with tracker info

12
Light Higgs search
If mh lt 140 GeV gg ? h ? ?? most promising
channel, although BR only 10-3
motivation for high resolution ECAL
(PbWO4 crystals 1 at 100 GeV)

13
Light Higgs search
_
Recent h ? bb in tth production
Also results on H? ??
14
Exclusive Higgs
A recent development search for exclusive Higgs
production pp? p H p
-jet
gap
gap
H
h
p
p
beam
-jet
Needs roman pots Cross section 1 fb
Khoze et al.
p
dipole
roman pots
dipole
p
roman pots
15
Invisible Higgs
16
Heavy Higgs

• at large tan ?, bb A/H and tb H? production
  strongly enhanced!!
• assume Msusy 1 TeV
• important channels

COVERED

• A/H ? ??
• A/H ? ??
• H? ? ??
• H? ? tb

Working hard to cover low tan? - high mA region
17
Heavy MSSM Higgs search (3)
NEW at low tan ?, we may exploit the sparticle
decay modes
A, H ? ?20 ?20 ? 4l ETmiss
F. Moortgat
18
Susy measurements
Atlas physics TDR
19
Susy
Mostly ? complicated decay chains
20
Susy
Decay chain example
21
Susy discovery limits
S. Abdoulin
22
Susy discovery Limits
S. Abdoulin
23
Susy measurements
Atlas physics TDR LHC Point 5
m0100 GeV m1/2300 GeV tan?
2.1 sgn(?) A300 GeV
24
Susy measurements
Atlas physics TDR
25
Benchmark points
26
Benchmark Points
27
Study of point B (SPS1)
M. Chiorboli
28
Decay chain

• Event final state
• ? 2 high pt isolated leptons OS
• ? 2 high pt b jets
• missing Et

29
First step c20 ? ll- c10
10 fb-1
Fit result
Etmiss gt 50 GeV
30
Sbottom reconstruction
Assuming M(c10) known!
31
Sbottom mass
10 fb-1
Result of fit
Generated masses
32
Gluino reconstruction
Etmiss gt 150 GeV
33
Gluino mass
10 fb-1
34
with 60 fb-1
60 fb-1
Result of fit
35
Point G
36
Sbottom peak
Result of fit
Generated masses
37
Guino peak
Result of fit
Generated mass
38
estimation

Generated values
This needs better understanding of the SM bkg
behaviour!
39
Conclusions
Point G, with 60 fb-1

• Sbottom and gluino seem to be visible

40
Stop Searches
Missing ET and transverse l? mass
Stop mass and cross section
Channels
S/?B for SM and SMSUSY
41
Rare Top Decays
S. Slabospitsky
42
Graviton Searches
Traczyk, Wrochna
MG1000 GeV C0.01
KK excitations in the RS model
Search Reach
MG2000 GeV C0.01
43
?? physics

• observation provided efficient measurement of
  forward scattered protons, one can study
  high-energy ?? collisions at the LHC

• Highlights
• gg CM energy W up to/beyond 1 TeV (and under
  control)
• Large photon flux F therefore significant gg
  luminosity
• Complementary (and clean) physics to pp
  interactions, eg studies of exclusive production
  of the Higgs boson, W pairs might be possible
  opens new field of studying very high
  energy gg physics

44
Two-photon interactions at the LHC
total ?? cross section .
45
?? physics
SUSY
Higgs
H0
s 10 pb (at WMH200 GeV)
clean signatures both transversal and
longitudinal missing energy !
it cannot be missed!!
46
And more
-Precision measurements MW to 15 MeV, Mtop to
1.5 GeV anomalous gauge couplings, sin2?W,
rare top decays, B-physics, CP violation
studies -MSSM Higgs bosons -Extra dimensions -New
heavy gauge bosons -Strong interactions in the W
sector -Technicolor -Compositeness up to scales
of 40 TeV
MSSM Higgs
New W boson
W mass
Top quark mass
LHC detectors must be prepared for the unknown