Toward an Understanding of
the Building Blocks of Nature
From Feynman-Field to the LHC
Rick Field
University of Florida
Outline of Talk
 Before Feynman-Field
University of Florida
October 18. 2008
 Feynman-Field Phenomenology
 CDF Run 2
 Looking forward to the LHC
FL-AAPT Meeting
October 18, 2008
CDF Run 2
Rick Field – Florida/CDF/CMS
CMS at the LHC
Page 1
Before Feynman-Field
Rick & Jimmie
1968
Rick & Jimmie
1970
Rick & Jimmie
1972 (pregnant!)
Rick & Jimmie at CALTECH 1973
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Rick Field – Florida/CDF/CMS
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Toward and Understanding of
Hadron-Hadron Collisions
Feynman-Field Phenomenology1
Feynman
From 7 GeV/c
and
hat!
Field
Outgoing Parton
p0’s
to 600 GeV/c
Jets. The early days of trying to
understand and simulate hadronhadron collisions.
PT(hard)
Initial-State Radiation
Proton
AntiProton
Underlying Event
Outgoing Parton
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st
Rick Field – Florida/CDF/CMS
Underlying Event
Final-State
Radiation
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The Feynman-Field Days
1973-1983
“Feynman-Field
Jet Model”
 FF1: “Quark Elastic Scattering as a Source of High Transverse Momentum
Mesons”, R. D. Field and R. P. Feynman, Phys. Rev. D15, 2590-2616 (1977).
 FFF1: “Correlations Among Particles and Jets Produced with Large Transverse
Momenta”, R. P. Feynman, R. D. Field and G. C. Fox, Nucl. Phys. B128, 1-65
(1977).
 FF2: “A Parameterization of the properties of Quark Jets”, R. D. Field and R. P.
Feynman, Nucl. Phys. B136, 1-76 (1978).
 F1: “Can Existing High Transverse Momentum Hadron Experiments be
Interpreted by Contemporary Quantum Chromodynamics Ideas?”, R. D. Field,
Phys. Rev. Letters 40, 997-1000 (1978).
 FFF2: “A Quantum Chromodynamic Approach for the Large Transverse
Momentum Production of Particles and Jets”, R. P. Feynman, R. D. Field and G.
C. Fox, Phys. Rev. D18, 3320-3343 (1978).
 FW1: “A QCD Model for e+e- Annihilation”, R. D. Field and S. Wolfram, Nucl.
Phys. B213, 65-84 (1983).
My 1st graduate
student!
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Hadron-Hadron Collisions
FF1 1977 (preQCD)
 What happens when two hadrons
collide at high energy?
Hadron
Hadron
Feynman quote from FF1
???
“The model we shall choose is not a popular one,
 Most of the time the hadrons
ooze
so that we will not duplicate too much of the
through each other andwork
fall apart
(i.e.who are similarly analyzing
of others
no hard scattering). The
outgoing
various
models (e.g. constituent interchange
particles continue in roughly
the same
model, multiperipheral
models, etc.). We shall
Parton-Parton Scattering Outgoing Parton
assume
direction as initial proton
andthat the high PT particles arise from
“Soft” constituent
Collision (no large transverse momentum)
direct hard collisions between
antiproton.
quarks in the incoming particles, which
Hadron
Hadron
 Occasionally there will
be a large
fragment
or cascade down
into several hadrons.”
transverse momentum meson.
Question: Where did it come from?
 We assumed it came from quark-quark
elastic scattering, but we did not know
how to calculate it!
Outgoing Parton
high PT meson
“Black-Box Model”
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The Simple Structure of
Our Universe
 Elementary Particle: Indivisible piece of matter without
internal structure and without detectable size or shape.
Mass and charge
located inside sphere
of radius zero!
 Four Forces:
Gravity (Solar Systems, Galaxies, Curved Space-Time, Black
Holes)
Electromagnetism (Atoms & Molecules, Chemical Reactions)
Weak (Neutron Decay, Beta Radioactivity)
Strong (Atomic Nuclei, Fission & Fusion)
 Two Classes of Elementary Particles:
Leptons: Do not interact with the strong force (but may interact with weak, EM and gravity).
Quarks: Do interact with the strong force (may also interact with weak, EM and gravity).
 Quarks and Leptons have very different properties:
Quarks have fractional electric charge. Quarks are found only as constituents of composite
particles called hadrons (baryons have B not 0, mesons have B = 0). Leptons exist as free
particles.
Baryon
Number
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The Periodic Table
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Monte-Carlo Simulation
of Hadron-Hadron Collisions
 Color singlet proton collides
with a color singlet antiproton.
 A red quark gets knocked out of
the proton and a blue antiquark
gets knocked out of the
antiproton.
 At short times (small distances) the color forces
are weak and the outgoing partons move away
from the beam-beam remnants.
Jet
quark-antiquark
pairs
color string
Proton
Beam
Beam Beam
Remnants
Remnants
Remnants
AntiProton
Beam
Beam
Beam
Remnants
Remnants
Remnants
color string
quark-antiquark
pairs
Jet
 At long times (large distances) the color
forces become strong and quarkantiquark pairs are pulled out of the
vacuum and hadrons are formed.
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Rick Field – Florida/CDF/CMS
 The resulting event consists of
hadrons and leptons in the form
of two large transverse
momentum outgoing jets plus
the beam-beam remnants.
Page 8
Hadron-Hadron Collisions
 Proton-Proton or Proton-Antiproton Colliders:
Hadron
Hadron
???
u
u
u
d
d
Ebeam
½Ebeam
FL-AAPT Meeting
October 18, 2008
1/6E
beam
½Ebeam
u
u
ECM ~ ¹/3 Ebeam
u
+
1/6E
beam
Rick Field – Florida/CDF/CMS
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Telagram from Feynman
July 1976
SAW CRONIN AM NOW CONVINCED WERE RIGHT TRACK QUICK WRITE
FEYNMAN
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Letter from Feynman
July 1976
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Letter from Feynman Page 1
Spelling?
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Letter from Feynman Page 3
It is fun!
Onward!
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The Fermilab Tevatron
Proton
CDF
1 mile
AntiProton
Proton
2 TeV
AntiProton
 Fermi National Laboratory (Fermilab) is near
Chicago, Illinois. CDF and DØ are the the two
collider detector experiments at Fermilab.
 Protons collide with antiprotons at a center-ofmass energy of almost 2 TeV (actually 1.96 TeV).
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Fermilab
Collider Detector Facility
Proton
CDF
1 mile
AntiProton
 At Fermi National Laboratory
(Fermilab) near Chicago, Illinois
there is a Proton-Antiproton
Collider.
 CDF is one of the two collider
detectors at Fermilab (the other is
called DØ).
Proton
2 TeV
AntiProton
 Protons collide with antiprotons at a center-of-mass energy of 2 TeV.
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High Energy Physics
Proton-antiproton collisions at 2 TeV.
 Define EH to be the amount of energy
required to light a 60 Watt light bulb for
1 second (EH = 60 Joules). 1 TeV = 1012
ev = 1.6×10-7 Joules and hence EH =
3.75×108 TeV.
Proton
 A proton-antiproton collisions at 2 TeV is
equal to about 3.2×10-7 Joules which
corresponds to about 1/200,000,000 EH!
The energy is not high in every day
standards but it is concentrated at a
small point (i.e. large energy density).
 The mass energy of a proton is about 1 GeV and the
mass energy of a pion is about 140 MeV. Hence 2
TeV is equavelent to about 2,000 proton masses or
about 14,000 pion masses and lots of hadrons are
produced in a typical collision.
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Rick Field – Florida/CDF/CMS
-7
3.2x10
2 TeV J
AntiProton
Lots of outgoing hadrons
Display of charged
particles in the CDF
central tracker
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Collider Coordinates
xz-plane
x-axis
x-axis
Beam Axis
Proton
P
cm
AntiProton
z-axis
Proton
“Transverse”
xy-plane
y-axis
AntiProton z-axis
 cm is the center-of-mass scattering angle and  is the
azimuthal angle. The “transverse” momentum of a
particle is given by PT = P cos(cm).
 Use h and  to determine the direction of an
outgoing particle, where h is the “pseudo-rapidity”
defined by h = -log(tan(cm/2)).
Rick Field – Florida/CDF/CMS
Azimuthal
Scattering Angle
y-axis
 The z-axis is defined to be the beam axis with
the xy-plane being the “transverse” plane.
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Center-of-Mass
Scattering Angle
PT

x-axis
h
cm
0
90o
1
40o
2
15o
3
6o
4
2o
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CDF Run II DiJet Event
July 2002
ETjet1 = 403 GeV
ETjet2 = 322 GeV
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Raw ET values!!
Rick Field – Florida/CDF/CMS
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High PT Jets
CDF (2006)
Feynman, Field, & Fox (1978)
Predict
large “jet”
cross-section
30 GeV/c!
Feynman quote from FFF
600writing,
GeV/c Jets!
“At the time of this
there is
still no sharp quantitative test of QCD.
An important test will come in connection
with the phenomena of high PT discussed here.”
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Rick Field – Florida/CDF/CMS
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Top Production at the Tevatron
 Top quark discovered in 1995
by CDF and DØ.
 Not a surprise: SM quark
sector now complete.
 Now study the detailed
properties of the top:
 Charge.
 Lifetime.
 Branching ratios.
 W-boson helicity.
 Make precision
measurements:
 Cross-sections now 12%!
 Mass now 2%!
 Measure single top production!
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Higgs Production
The next great challenge is to find
the Higgs Boson at the collider.
 Look for b-quark jets and
missing transverse energy.
“Higgs” Production


W
Proton
AntiProton
H
b
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b
Rick Field – Florida/CDF/CMS
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Tevatron Measurements
Jets
b-quarks
We are getting very close to
the Higgs and/or new physics!
W
Z
W+g
Single top
Z+g
W+W
tt
W+Z
Z+Z
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The New Forefront
 The forefront of science is moving
from the US to CERN (Geneva,
Switzerland).
Proton
14 TeV
Proton
 The LHC will collide protons with protons at a centerof-mass energy of 14 TeV (seven times greater energy
than Fermilab)!
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Where is CERN?
France
Switzerland
Lake Geneva
Alps
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CERN
 CERN - Centre European Research Nucleaire
 International HEP laboratory, founded in 1954
 20 member states, many associate states Actually, the Cathode Strip Chamber
 Built around 4 accelerators:
muon system shown in the picture was
built for CMS by the U.S., Russia, and
 Proton Synchrotron, built in 1950s
China with 100 of the larger chambers
 SPS, built in 1970s
coming from UF!
 LEP, built in 1980s, started in 1989
 LHC, physics startup 2008
 Budget is ~1B CHF (swiss franc) ~ $800M/year,
staff of ~3000
 Great location, and a world class cafeteria
 Coffee, wine, beer, desserts, open late
 Center of CERN social life
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The LHC at CERN
Me at CMS!
6 miles
CMS at the LHC
Darin
Proton
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14 TeV
Proton
Rick Field – Florida/CDF/CMS
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The Large Hadron Collider
(LHC)
 7 TeV on 7 TeV proton-proton collider, 27km ring
7 times higher energy than the Tevatron at Fermilab
• Aim for 5 TeV for 2008
100 times higher design luminosity than Tevatron (L=1034cm-2s-1)
 1232 superconducting 8.4T dipole magnets @ T=1.9ºK
Largest cryogenic structure, 40 ktons of mass to cool
 4 experiments
 Start Date:
Sept. 10, 2008
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LHC Experiments
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CMS Collaboration
Number of
Laboratories
Member States
59
Non-Member States
67
USA
Total
1084
Non-Member States
503
USA
723
Total
2310
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Bulgaria
Finland
CERN
France
Germany
Greece
Hungary
Russia
Italy
Uzbekistan
Ukraine
Georgia
Belarus
Armenia
Turkey
Serbia
Pakistan
Associated Institutes
Number of Scientists
62
Number of Laboratories 9
Belgium
Austria
USA
49
175
# Scientific
Authors
Member States
2310 Scientific Authors
38 Countries
175 Institutions
New-Zealand
UK
Brazil
China, PR
China (Taiwan)
Colombia
Croatia
Ireland India Cyprus
Estonia
Lithuania
Mexico Korea Iran
Rick Field – Florida/CDF/CMS
Poland
Portugal
Spain
Switzerland
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Point 5 (Cessy, France)
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CMS Assembly Building
Early 1999 start of construction
Surface hall foundations
Surface hall foundations
Surroundings near Point 5
Early 1999…
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CMS Pictures
Endcap yoke
and disks
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First LHC Beams at CMS
CMS Control Room
LHC Control Room
September 10, 2008
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UF Celebration in the CMS
Control Room, 11pm
September 10, 2008
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The Following Week
 Friday night, 12-Sep.
 11:20pm: Lose main 30ton 12 MVA transformer at Point 8 (LHCb)
 There are no spares, and it would take 6-9 months to procure another.
 “Borrow” from surplus capacity at CMS
 13-18 Sep, Hardware commissioning consolidation
 Power, cryogenic, and vacuum problems lead to 6 days of downtime
 Advance commissioning of magnet control system to 5 TeV beam operation for 2008 (avoid 10
day shutdown)
 CMS investigates issues with magnet
 Thu, 18-Sep
 Return to beam 1 operation
 CMS takes data overnight
 Friday noon, 19-Sep
 Massive helium loss in one arc of the tunnel
(1-2 tons), cryogenics lost
 Broke insulation vacuum in sector
 Suspected failure of interconnection between quadrupole and dipole magnet during 5 TeV
commissioning of last sector of LHC
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The Weeks to Come
After a brief start, the LHC program is
temporarily halted until spring 2009
Dear Colleagues,
We have today issued an analysis of the 19 September incident at the LHC.
Investigations have confirmed that cause of the incident was a faulty
electrical connection in a region between two of the accelerator's magnets,
which resulted in mechanical damage and release of helium from the magnet
cold mass into the tunnel. Proper safety procedures were in force, the safety
systems performed as expected, and no one was put at risk. Sufficient spare
components are in hand to ensure that the LHC is able to restart in 2009,
and measures to prevent a similar incident in the future are being put in place.
This incident was unforeseen, but I am now confident that we can make the
necessary repairs, ensure that a similar incident cannot happen in the future
and move forward to achieving our research objectives. October 16, 2008
 Several weeks needed to warm up sector and investigate damage
(~1 week more).
 Several magnets expected to be replaced.
 Not enough time to restart before winter shutdown.
 Winter shutdown activities to be advanced where possible.
 Decision to commission to 7 TeV design energy postponed until
after inspection and new risk assessment.
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October 18, 2008
Rick Field – Florida/CDF/CMS
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Why Build the LHC?
Puzzles in Particle Physics
Because there is so much we do not know!
Curiosity!
 The precision of Standard Model calculations depends on the Higgs mechanism in the theory,
which generates mass for particles
 But the Higgs boson has not yet been directly observed.
 Need higher energy and higher luminosity to increase production yield
 The Higgs mass must be fine-tuned to extremely high precision, as it receives radiative
Onward!
corrections to its mass
 Protected by Supersymmetry ?
• A symmetry sort of like antimatter, but with opposite spin rather than charge
(bosons  fermions)
• Not observed, presumably at a higher energy scale if it exists
 Protected by other new forces/particles?
 Protected by (compactified) extra dimensions?
• With possibility of microscopic Black Hole production
 Any unification of the fundamental forces?
 What is the dark matter in the universe ?
 Supersymmetry can lead to stable massive neutral particles
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