The LHC Adventure

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The LHC Adventure

• Sarah Eno, U. Maryland
• Colloquium
• Jan. 23, 2006, Cornell

Drawings by S. Cittolin
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A Novel by Dan Brown?
Oh ya, I read that
Nope! Its even more exciting than that!
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What is the LHC?
In the LEP tunnel

• pp ?s 14 TeV L1034 cm-2 s-110 mb-1MHz
• crossing rate 40 MHz (25 ns)
• circumference of 27 km (16.8 miles)
• Cost of about 3B? (depending on accounting
  method, conversion rate, etc)

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Countdown Clock
LHC Dipole March, 2005
March, 2005
CMS Detector, Sept. 2005
CMS Detector, Sept. 2005
T-521 days and constructing, building!!
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Brief History of Accelerators
Accelerators are traditionally used to study the
fundamental forces and particles
J.J. Thomsom uses a cathode ray tube to discover
the electron, measurement of e/m 1887
Rutherford scattering alpha particles on a thin
metal foil 1911 -gt nuclear model
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Colliders
ADA (Anello Di Accumulazione) First ee- collider
built in Frascatti, Italy, operated in Orsay,
France 1961-1964
Tevatron
http//www.lnf.infn.it/acceleratori/ada/
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New States of Matter
Annihilation diagrams
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Colliders
SppS was created as a discovery machine. All the
rest were just lets build it and see whats
there.
Slide from Dan Green
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Colliders Today
e(3.1 GeV) on e- (9 GeV)
Tevatron
PEP-II
pp collisions at 1.96 TeV
p (920 GeV) on e (27 GeV)
BELLE
HERA
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CESR
ee- workhorse since the late 70s
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Standard Model
Well-understood theory of forces/partices with 3
parts electroweak force, strong force, gravity
Higgs?!?!?
1960s EWK
1970s QCD
Complete theory of interactions at energy scales
below about 1 TeV?
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Modern Theory Electroweak
Higgs (M?????)
Photon (M0)
Z (M 90 GeV)
3 parameters g, qW, MW a coupling constant, a
mixing angle, and the higgs vev
Gauge invariant quantum field theory
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Modern Theory QCD

• A -gt gluons
• -gt quarks
• L, Fabc -gt Su(3) isoscalar factors and
  representation matrices

1 parameter theory -gt gs -gt as
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Modern Theory Matter
quarks
leptons
Mass/weak eigenstate mixing matrix
Parameters 6 quark masses, 6 lepton masses, 4
quark mixing parameters, 4 neutrino mixing
parameters.
A complete theory for laboratory collisions below
about 1 TeV?
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Modern Questions
What is with the matter sector, anyway?
Besides the fact that the EWK theory needs at
least 3 generations of doublets, equal numbers of
quark and lepton doublets, and 3 strong charges
for the quarks, everything else is a mystery.
No (non-speculative) theory for their values.
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Dark Matter
S. Smith, ApJ 83, 23 (1936)
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Dark Matter/Dark Energy
cmb cosmic microwave background (wmap)
2003 Supernovae brightness of distant
supernovae 1999 Clusters rotation of clusters
of galaxies (Zwicky1933, Smith1936, Oort 1940,
Rubin1962, but ignored until late 70s)
30 of Universe is matter Rest is dark energy.
Feng,astro-ph/0511043 Olive, astro-ph/0503065 Rubi
n Millennium Essay PASP
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Dark Matter/ Dark Energy
Big bang nucleosynthesis, light element
abundances, and CMB all say only 4 of the
Universe is ordinary matter
Should be a particle with mass around a GeV,
weakly interacting, electrically neutral, no
strong charge from WMAP data and cosmological
constraints
There is no good candidate among the known
particles for the Dark Matter.
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Modern Questions
Unification of Forces?
Planck mass 1019 GeV
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Higgs
Spin zero, electrically neutral boson In the
standard model, the reason the W and Z bosons
have a mass around 100x that of the proton while
the photon is massless is because of the Higgs
boson. Allows fundamental fermions to have mass
as well Also, the J0 partial wave amplitude for
WL WL scattering violates unitarity at high
energy if there is no Higgs.
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Modern Questions
Where is the Higgs?
And, anyway, this Higgs particle is weird
The problem with scalars...
102 GeV 1016 GeV
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Higgs
From Theory
Trivial theory To avoid having the minimum Higgs
potential at - infinity Vacuum Stability To
make sure that the higgs potential has a minimum
that is lower than V(0) requires new physics
above this scale.
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Modern Answers
Can a new high energy collider, such as the LHC,
help us with these questions?
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Higgs
From Experiment
M(H)gt114.4 GeV
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Electroweak Theory
Higgs
W
photon
Z
Can predict any other observable. At LEP, in
particular, sin2qW At Tevatron, MW
However, parameters from the matter sector can
come in through loops
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M(Z)
At Tree Level
At higher order, because of diagrams that look
like
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GF
From muon lifetime
Ritbergen and Stuart Phy. Rev. Lett. 82, 488
(1999),
Giovanetti et al (1984) (also, in same year,
Bardein et al)
Uncertainty is dominanted by experiment
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MZ
From LEP lineshape
0.002 measurement
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alpha
At low Q2

• From
• ee- anomalous magnetic moment
• quantum Hall Effect

At high Q2
Jegerlehner
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alpha
Jens Erler, Phys. Rev. D59, 054008 (1999)
.01 measurement
Particle data group, lbl, http//pdf.lbl.gov
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Top Mass from LEP
1992
Phys. Lett. B 276 (1992) 247
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Higgs
At higher order, because of diagrams that look
like
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Direct/Indirect Evidence
LEP EWWG http//lepewwg.web.cern.ch/LEPEWWG/
M(H)gt114.4 GeV direct search
Is it just out of reach of current colliders?
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Modern Answers
For the higgs is a scalar problem and the rest
of the modern questions, just have speculative
answers
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Supersymmetry?
Postulate a new particle,
is just like H, except it has spin 1/2
The two diagrams cancel.
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Dark Matter Candidate
Lightest scalar fermion (neutalino) is a dark
matter candidate
Feng, astro-ph/0511043
Goldberg, Phys. Rev. Lett. 50, 1419 (1983) Ellis,
Haagelin, Nanopoulos, Olive, Srednicki, 1984
(Nucl. Phys. B 238, 453)
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SUSY
supersymmetry
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Modern Answers
Can pp collisions at sqrt(s)14 GeV help us
answer any of these questions?
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Particle Production in pp
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Cross Sections versus Mass
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Particle Production
1 snow mass year 107 s
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Higgs Production Kinematics
Higgs production at LHC is dominated by gluon
fusion.
?
H
?
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Higgs Decay
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Higgs Reach/Time Scales
If we can start up at 1/10th design luminosity,
well discover a Higgs with mass greater than 130
GeV within 1 year. Will cover entire
theoretically allowed range with 1 year of design
luminosity.
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SUSY
backgrounds
SUSY 600 GeV squark
Dramatic event signatures (LSP) and large cross
section mean we will discover SUSY quickly, if it
exists.
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SUSY reach/ TimeScales
Cosmologically plausible region of parameter
space covered within 1 year 1/10th design
luminosity. 1 year of design luminosity covers
all regions interesting for EWK symmetry breaking
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Can we really do it fast?
1983
The SppS turned on at 1 of final instantaeous
luminosity, but in the first run of a few months
discovered the W and Z bosons.
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Time
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CERN
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LHC History
1989 LEP comes on line (originally planned to
someday run protons) 1977-1978 SSC is proposed
after a series of accelerator workshops 1983
preliminary SSC design work 1987 SSC approved by
President Reagan 1993 Chris Llewellyn Smith and
others propose LHC, to be built in LEP
Tunnel 1993 SSC is cancelled. 1994 project
approved by CERN council for 2002 turn-on. 2000
LEP shut down so LHC construction could start
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LHC (cont)
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Its big
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Really big
Lake Geneva
Jura Mountains
The Alps
Geneve
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LHC Parameters
Particles used Protons and heavy ions (Lead,
full stripped 82) Circumference 26,659 m.
Injector SPS Injected beam energy 450 GeV
(protons) Nominal beam energy in physics 7 TeV
(protons) Magnetic field at 7 TeV 8.33 Tesla
Operating temperature 1.9 K Number of magnets
9300 Number of main dipoles 1232 Number of
quadruples 858 Number of correcting magnets
6208 Number of RF cavities 8 per beam Field
strength at top energy 5.5 MV/m RF frequency
400.8 MHz Revolution frequency 11.2455 kHz.
Power consumption 120 MW Gradient of the
tunnel 1.4 Difference between highest and
lowest points 122 m.
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LHC Parameters
Beam energy 7 TeV protons/bunch 1.15x1011
bunches 2808 Bunch spacing 25 ns Machine
current 0.6 A Stored energy 362 MJ Total mass
in machine 2.5x10-13 g
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362MJ is a lot of energy
Enough energy to change 1 ton of water 100
degrees Celsius
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LHC/LEP Tunnel

• 27km long bored deep underground tunnel
• 3km are actually under the Jura mountains
• Diameter 4 - 6m
• Depth 50 - 175m depending on location
• 1.4 x 106 m3 (100m)3 soil extracted to dig it

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Dipoles

• Superconducting, 15m length, 35 tons of mass
• First dipole lowered 7 Mar 2005 1231 more to go!

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Installing Dipole Magnets
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Hardware Commissioning and Injection Test

• Aim to send beam
• Out of SPS TT40 ?
• Down TI8 ?
• Inject into LHC R8
• Through insertion R8
• Through LHCb
• Through IP8
• Through insertion L8
• Through arc 8-7
• To dump at Q6 R7

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LHC Schedule

• LHC on schedule for
• October 2006 possible injection test through
  sector 8
• June 2007 end of commissioning and alignment all
  sectors, ready for beam
• CMS Ready to close June 30, 2007 or earlier
• Full detector running in early 2008

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The Detectors
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LHCb
Studies of the b quark
Turns on at the same time as ATLAS and CMS Looks
like a fixed target experiment covers 1.9lthlt5.3
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Alice
Pb-Pb Collisions
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CMS ATLAS

• about 0.5B? a piece
• CMS is 14.6 m tall, ATLAS is 20 m tall.
• CMS has 2602 members, ATLAS 3598
• US is 20 of CMS, 13 of ATLAS

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Growth of Detectors
CMS, 2007, 2600 authors, 48 ft high
DØ, 1994, 351 authors, 28 ft high
AMY, 1988, 102 Authors, 18 ft high
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CMS in UX5
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Heavy Lowering
Heavy lowering starts Feb 2006. 15 major lifts.
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Point 5 ( a couple of years ago)
Installation Shaft
SX5
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Experiment Cavern UXC55 delivered to CMS
UXC55 Feb 05
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Pt5 underground progress USC 55
Impressively complex installation in service end
of cavern. Cooling plant installation starts this
month
Control end work progressing well estimate ready
for crates in Dec 05.
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The Experiments
Studying the weak force
Rutherford showed radioactived contained 3 types
of decays, alpha, beta, gamma wrap some Uranium
in aluminum foils. Study count rate versus foil
thickness. Chadwick showed for beta decay that
the electron does not take all the energy of the
decay collimated source and a magnet (our
tracking systems use magnets) Ellis and Wooster
showed missing particle is not photon radium
inside a calorimeter. Compared total energy in
calorimeter to energy measured by Chadwick. ( we
use calorimeters, though we read charge, not
temperature)
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Slice of CMS
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Radiation Level CMS Inner Detector
Dose rate during LHC running 15 rad/h in Barrel
/ up to 1500/h rad in Endcap
CMS ECAL is the first large crystal calorimeter
to be operated in a harsh radiation environment.
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Slice of CMS
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Solenoid
6m
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Solenoid Fun Facts

• diameter 6 m (20 ft) (AMY would fit inside
  it)
• Largest one ever built
• stores 2.7 GJ of energy

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Solenoid Fun Facts
Resistive load dump
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Solenoid
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Solenoid Onsite Cabling

• Aluminum extruder and assembler for cables
• Cabling machine for winding

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Solenoid built vertically, then swiveled for
horizontal installation
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Solenoid (pictures)
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Slice of CMS
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CMS Tracker
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Tracker Fun Facts

• tracker is made from silicon
• inner tracker 76,000,000 channels
• measures about 14 points along trajectory to
  20-35 mm
• forward tracker, 45,000,000 channels
• total area 210 m2

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Tracker Coverage
A schematic of one quarter of the CMS Tracker
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Tracker at CERN
High tech!
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TIB Layers 2, 4 at Pisa
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Slice of CMS
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ECAL
61200 barrel crystals
14648 endcap crystals
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ECAL Fun Facts

• new generation of calorimeters made from PbWO4
  crystals (Alice (phos), Panda (2012))
• signal is light produced in the crystal.
• 75848 crystals , each 2.2cmx2.2cmx23cm with
  density 8.28 g/cm3
• each crystal weighs 3 lbs.

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Cutting Raw PWO Ingots at BTCP
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ECAL Crystal Matrix Production
Single Crystal
Sub - Module mounting
Assembled Sub - Modules
Free mounting bench
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Barrel Supermodule Construction
Module 400/500 crystals
Bare Supermodule 1700 crystals
Assembly status - end of December 2005 22 Bare
Supermodules (60) 4 Supermodule electronics
1 Supermodule operated for 4 Months
SM10 with electronics - November 2004
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Testbeam Measurements at CERN SPS
ECAL Test Area
Insulated Hall
Air Conditioning

• Electrons, pions, muons
• Precisely known energies
• Supermodules on moveable table
• Study of energy resolution, irradiation effects
  etc.

Moveable Table with ECAL Module
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Slice of CMS
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HCAL
Had Barrel HB Had Endcaps HE Had Forward
HF Had Outer HO
HO
HB
HE
HF
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HCAL Fun Facts

• brass for detector came from Russian artillery
  shells
• electronic signal is made by scintillating
  plastic
• 4608 towers

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HCAL Status
HB
HE
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HCAL
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Shiny Brass
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Slice of CMS
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Muon System
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Muon System Fun Facts

• 10k ton iron return yoke Eiffel tower
• return flux through the iron allows for a second
  measurement of the muon momentum (aside from the
  one done in the silicon)
• signal created in gas volumes in between the
  iron (update on an old fashion, 1960s
  technology)
• 25000 m2 of active detection planes
• 1,000,000 electronic channels
• measures muon trajectory to 100 mm at (up to) 44
  points along the track.

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DT Chamber prod. Site

AACHEN
CIEMAT
TORINO
LEGNARO
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Installation of DT chambers YB2
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Endcap CSC Installation

• 468 chambers needed
• 100 tested and at CERN
• 60 installed
• 50 commissioned

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CSC on YE
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Muon Status

• Barrel beginning installation of chambers in
  yoke assembly now
• Endcap one side already completestarting to
  load CSC chambers
• No problems anticipated here

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Data?
Remote Operations Center LHC_at_FNAL
Virtually there, 24/7
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Cosmic Muon Data
1 top / 1 bottom (now)
MTCC 4 top / 4bottom
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Cosmic Data
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CMS Collaboration
Ordered by size USA (525 collaborators), Italy
(398), Russia (326), CERN (204), France (146), UK
(117), Germany (116)
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Tiered System for Data Mgmt

• T0 at CERN
• Record raw data and DST
• Distribute raw data and DST to T1s

FNAL Chicago
RAL Oxford
T1
T1

• T1 centers
• Pull data from T0 to T1 and store
• Make data available to T2

FZK Karlsruhe
T1
T0
T1
T1
CNAF Bologna
T1
IN2P3 Lyon

• T2 centers
• DST analysis.
• Local data distribution

PIC Barcelona
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Conclusions
Truth is stranger and more fun than fiction.
Stay tuned for exciting discoveries in 2007!
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Particle Production in pp Collisions
W
W