Summary%20of%20the%20Electroweak%20Symmetry%20Breaking%20working%20group%20Part%201:%20Experiments

1
Summary of the Electroweak Symmetry Breaking
working groupPart 1 Experiments

• Dhiman Chakraborty
• Northern Illinois University
• WIN07, Kolkata, India
• 15-20 January, 2007

2
Informative, stimulating, engaging talks from
collider experiment collaborations

• Reports from the LHC, Tevatron, HERA
• Experiment status and commissioning (2)
• Electroweak measurements (3)
• Studies of the top quark (2)
• Higgs searches (1)
• Searches for physics beyond the Standard Model (3)

3
CMS status, commissioning and early physics
prospects (L. Malgeri)
4
CMS physics roadmap
Z
?f
_at_6TeV
Z
?f
_at_6TeV
ADD X-dim_at_9TeV
ADD X-dim_at_9TeV
SUSY_at_3TeV
SUSY_at_3TeV
3000
3000
Compositeness_at_40TeV
Compositeness_at_40TeV
H(120GeV)
H(120GeV)
?
??
gg
?
300
300
????????????
Higgs_at_200GeV
SUSY_at_1TeV
SUSY_at_1TeV
/yr
30
30
-1
200 fb
10-20
10-20
1000 fb
/yr
1000 fb
/yr
100 fb
/yr
-1
-1
100 fb
/yr
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fb
/yr
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First physics run O(1fb-1)
5
Summary

• CMS assembling and commissioning is going full
  speed
• No major obstacles foreseen on the road
• Recent MTCC, software challenges have proven
  that
• CMS can work with full magnetic field
• CMS sub-detectors can work as a single detector
• The DAQ and (new!) software is ready for
  prime-time
• CMS started to be lowered in the pit
• A full physics commissioning plan is setup
• alignment and calibration
• re-discover SM
• possible early discoveries

Initial CMS will be ready for collisions in 2007
6
ATLAS detector status and early physics (S.
Tanaka)
Length 45 m Height 25 m Weight 7000
tons Electronic channels 108 3000 km of
cables

• Inner Tracking (?lt2.5, B2T)
• Silicon pixels and strips
• Transition Radiation Detector (e/?
  separation)
• Solenoid B2T
• Calorimetry (?lt5)
• EM Pb-LAr with Accordion shape
• HAD Fe/scintillator (central), Cu/W-LAr
  (fwd)
• Muon Spectrometer (?lt2.7)
• Air-core toroids with muon chambers
  (Trigger Precise measurements)

7
ATLAS physics roadmap

• With early 14 TeV run,
• (10pb-1) Study minimum-bias, di-jet, pile-up
  events
• (100pb-1) Missing ET,, Jet Energy calibration
  (-gt SUSY, Higgs)
• Top , W, Z , QCD b-jet (SM
  processes)
• ( few fb-1) Early Higgs search (H-gtWW-,ZZ)
• SUSY, BSM search (Miss ET,
  Di-Jet, Di-Lepton..)
• End of 2008 will be record few fb-1 data.

8
ATLAS summary

• The ATLAS detector is well on its way to be ready
  in 2007.
• Magnets Solenoid, Barrel Toroid operation
  OK.
• End-cap Toroid will be install but
  some delay
• Inner Tracker SCTTRT Barrel installed
  (Cosmic ray test independently)
• End-cap will be install in Feb 2007.
• PXCEL will be install in April
  2007. (Schedule is tight)
• Calorimeter Barrel LAr Tile Installed and
  start cosmic run
• End-cap will start cold
  operation from April 2007.
• Muon Barrel parts (MDTRPC) installed (some
  segments start cosmic run)
• End-Cap 1 TGC Big Wheel (need 6
  wheels) has installed
• MDT Wheel is now installing
• (will be install before beam
  closing)
• From autumn 2007, we will start to record 900 GeV
  data and calibrate detector response for
  preparing 14 TeV run.
• ATLAS will be ready to enter the new high energy
  scale in 2008.

9
Electroweak results from the Tevatron (C. Hays)

• New CDF measurement of W mass is world's most
  precise

Central value up by 6 MeV to 80398 MeV World avg
uncertainty reduced by 15
SM Higgs mass constrained to 8036-26 GeV
10
Tevatron electroweak summary

• High-luminosity data samples are opening new
  physics windows.
• Most precise determination of W mass (CDF)
• Expect lt25 MeV precision with 1.5 fb-1 data
  already collected.
• First observation of WZ production
• Expect most sensitive probes to anomalous WWZ
  couplings.
• First hint of W??radiation amplitude zero
• Expect to observe this quantum interference
  effect.
• Many other measurements of W and Z boson
  properties constraining couplings and PDFs.

11
Electroweak results from HERA (E. Rizvi)

• Direct measurement of parity violation in neutral
  current interactions

12
HERA electroweak summary

• Many interesting results coming from HERA
  experiments
• NC CC measurements at EW scale
• Improvement of statistical precision through H1
  ZEUS combination
• Clear observation of parity violation in NC
  channel
• Simultaneous QCD EW fits performed on HERA
  data
• Determination of spacelike propagator mass in CC
  interactions
• Polarised CC date give direct sensitivity to WR
  ? limit set
• Extraction of light quark couplings to Z0
• The Standard Model holds up extremely well
• Last six months of HERA operation
• Final analysis of complete HERA dataset will
  follow...

13
EW physics at the LHC (K. Mazumdar)

• Precision measurements can be done with early
  data.
• Stat. uncertainties will be negligible, thanks to
  huge cross sections.
• Final precision will be limited by understanding
  of physics and detector response.
• Knowledge of total luminosity will drive cross
  section measurements.
• Excellent momentum and energy resolution for
  leptons (all flavors) and jets (both light and
  heavy) will be crucial requires accurate and
  precise alignment of detector elements (lt1 ?m for
  inner tracking).
• High potential for tests of the SM through
  precision EW measurements.

14
Studies of the top quark at Tevatron (E. Aguilo)
15
Top mass measurement at the Tevatron

• Many analyses

16
Evidence of single top production (via
electroweak processes) at the Tevatron
EVIDENCE!!!
17
Tevatron top quark summary

• Rich program at Tevatron leading into the LHC
  era.
• July 2006 Tevatron combined top mass
• mt 171.4 1.2 1.7 GeV
• dominated by the CDF leptonjets measurement
• mt 170.9 1.6 2.0 GeV
• The precision is better than expected!
• CDF combined top pair production cross section
• ??tt) 7.3 0.5 0.7 pb
• Evidence of electroweak single top production has
  been found at DØ with the Decision Trees
  analysis. Measured cross section
• ????t) 4.9 1.4 pb (3.4?)
• And a first direct measurement of Vtb has been
  made
• 0.68 lt Vtb lt 1 _at_ 95 CL

18
Top physics at the LHC (G. Steinbrück)

• Pair production cross section 870 pb (NLO),
  i.e. 120x tevatron Run 2.
• 87 via gluon fusion, 13 via quark
  annihilation
• Rate 1Hz at 1033cm-2s-1?LHC is a top factory
  unlike the Tevatron.
• ?Differential x-sec become more powerful!
• Single production rate enhanced similarly
• Many detailed studies have been done by ATLAS and
  CMS to determine the physics potential and the
  challenges for (top) physics.
• Top mass measurement is expected to reach the
  precision of 1 GeV.
• Tests of the SM through spin correlation,
  production kinematics
• Searches for new physics through deviations from
  SM predictitons

19
(SM) Higgs physics at the LHC (L. Feligioni)

• Gluon Gluon fusion
• Dominant production mode
• NLO correction important
• K 1.7
• Main contribution is gluon radiation
• many events with at least one jet
• NNLO cross section known
• Sig(NNLO)/Sig(NLO) 1.3
• Vector Boson Fusion
• small K factor 1.1
• Small jet multiplicity in final state
• No color exchange between quarks
• large energetic jets at small pT
• Low hadronic activity in central region from hard
  event
• a part from Higgs decay
• Production with Gauge boson
• Known NNLO for QCD and EW corrections
• Production with heavy quarks
• More complicated final state

20
(SM) Higgs decay

• Light Higgs (110ltmH(GeV)lt130)
• Dominant mode is H?bb (75-50)
• H?????? and cc with 3-7
• Higgs decay to ???? through top loop
• H??VV() rises close to MH 130 GeV
• Intermediate Higgs
  (130ltmH(GeV)lt180)
• H?VV() most important
  decay mode
• Heavy Higgs (180ltmH(GeV)lt1000)
• H?VV
• For mH400 GeV the decay in two top quarks also
  plays a role
• All BR calculated at NLO, error within few

21
LHC sensitivity to (SM) Higgs

• CMS studies based on NLO calculations, ATLAS on
  LO (NLO studies in progress)

22
LHC Higgs summary

• Early discoveries (10 fb-1) could be possible
  for H??VV at large mass
• Low mass region more challenging
• optimized H?????? analyses predict discovery
  after 3 years
• other channels can be exploited ttH, VBF
• Good understanding of detector needed to assess
  performances and understand background shapes
• Less than one year to first collisions!
• getting ready for data

23
Searches at Tevatron for beyond-SM physics(S.
Banerjee)

• Both D0 and CDF have been conducting searches for
  numerous new physics scenarios
• SUSY (mSUGRA, GMSB, RPV, ...)
• Extra dimensions
• Leptoquarks, heavy gauge bosons, ...
• No significant departure from SM predictions
  found yet, but continuing to analyze more data
  and reduce systematics in order to improve
  sensitivity
• Sorry, I could not extract any material from the
  talk - my laptop refuses to open the file!!!

24
Searches at the LHC for beyond-SM physics(R.
Ströhmer)

• ATLAS CMS have significant discovery potential
  for physics beyond the standard model. Much
  effort is invested in estimating and maximizing
  these.
• New physics could already show up in early data.
• In order to claim a discovery on needs to
  understand the background
• detector performance
• standard model processes
• discovery of something is only first step, the
  second is to distinguish between models and
  determine parameters.

25
Searches at HERA for beyond-SM physics(A. Raval)

• Model dependent searches
• Leptoquarks
• Lepton flavor violation
• Excited fermions
• Single top production
• Doubly charged Higgs
• Supersymmetry

• Model independent searches
• Events with isolated leptons and missing ET
• Tau production
• Multi-lepton production
• Magnetic monopoles
• General searches

• Limits from precision measurements
• NC DIS CI, LEDs, quark radius
• CC DIS Right-handed weak currents

26
Summary of HERA searches for BSM physics

• New results on
• Leptoquarks
• Compositeness
• Large Extra Dimensions
• Excited fermions
• Supersymmetry
• HERA results competitive in most areas and
  complementary in others
• Interesting excess/fluctuations (H1 excess in
  high-pT multiilepton events not confirmed by
  ZEUS) !?
• Still more HERA II data to come (until March 07)

27
Summary

• This summer HERA will conclude 14 years of
  successful studies of lepton-neucleon scattering
  at the highest energies
• Tevatron is going strong, expected to run till
  2009 (20 years!). Exciting results have been
  emerging steadily. Many more are expected. SM
  is still holding its ground. Search for the
  Higgs and new physics are on - more data than
  current have yet to come.
• LHC experiments are on course to start taking
  data this year. Revolutionary discoveries of new
  physics are expected in the coming years.
• For details, see the many excellent talks at this
  conference - thanks to all the speakers.
• Thanks to the organizers for hosting this
  fruitful and enjoyable event, and to the
  participants for making it a success.