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The Big-Bang Machine
Stefan Spanier
Physics and Astronomy
University of Tennessee, Knoxville
25 February 2017
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Accelerator = Microscope
Length to be resolved L
1/Particle Energy
Pocket Electron-Accelerator
-
-
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Energy
L
+
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Particle Collider Experiment Principle
Particle
Accelerator
provides large
kinetic energy
Very High Voltage
(year 1932)
E = m c2
short lived particle –
new matter?
Particles live long enough to make
signals in a detector (material)
- create light
- generate new particles
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Particle Collider Experiment Principle
Measure many particles
e.g. their energy …
more like
exists ~10-23 seconds
Background
Lifetime
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1 / Width
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Signal
4
The Standard Model Building Blocks
Proton
d
u
Latest addition 1995
Tevatron at Fermilab
u
hadrons
Quarks
Leptons
_
d
particles
u
c
t
d
s
b
e-
_
u
_
u
Anti-proton
anti-particles
_
d
_
u
_
s
_
c
_
b
_
t
_
_
_
e
e+
e
mass
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Particles and Forces
+
+
+
2
Force
Charge
2
Distance
Coulomb law, 1783
Franklin, June 1752
Electric Force: same sign electrical charges repel each other
even at infinite separation
Electromagnetic Force: Unification electricity+magnetism
Maxwell ~1861
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Particle Interactions
Time
Particle Physics (Quantum Field Theory) Started ~ 1925
Photon
virtual photon
+
Range
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MassBoson
Coupling
to Charge
MassPhoton
+
0
Range
Theory works extremely well
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precision within ten parts in a billion
7
Particle Interactions
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Particle Interactions
Radioactive Decay
Weak Force
~10-15m
u
e-
~10-18 m
W
e-
-
d
Neutron
Range
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Proton
1
MassBoson
MassW ~ 80
MassProton
Could the forces be the same?
What is the underlying important principle?
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Standard Model Fundamentals
The SM is a Quantum Field Theory:
describes all interactions as exchange of particles
1) Force laws must apply at all places and times
gauge invariance (know how to calibrate)
2) Predicted reaction rates should be finite at all energies
renormalizable
Turns out: Theories based on principle 1)
deliver predictions with high precisions
But: To work everywhere
the force particles need to be massless !!!
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Noble Price 2013
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The Higgs Mechanism
How particles acquire masses …
The Higgs particle
mass generation
Standard Model safe !
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????
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Why should it be safe?
The Standard Model has ~ 18 (+9) dials (parameters) that are
adjusted in agreement with measurements - precisely
They are not a fundamental outcome of the present theory
= appear to be arbitrary settings - could be linked
Arbitrariness is Ignorance –
we do not know yet the more fundamental theory – what is it?
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Standard Model in Everyday Life
e.g. the W-boson controls the Sun
this weak force process starts the cycle that fuels the Sun:
p
e+
p
pn
Deuterium
Set W mass dial to lower value
Sun hotter, brighter
more UV light
W mass is given by Higgs interaction, but not its value
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The Time Machine
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1 meV Today ( T= 2.7 K )
~ 13.7 billion years
TimeThe Bigger
Picture – if this
is it …
Solar system
Galaxy formation
400,000 yr
1s
Nuclei form (D, He, Li)
10-8 s
Quark
LHC
10-12 s
protons, neutrons form
103 GeV Higgs acts Why here?
Particle Desert: Are there more particles ?
10-35 s
Big Bang
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10-43 s
1015 GeV Unification of electroweak
and strong force
1019 GeV Planck Epoch ( T~1032 K )
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Grand Unification of Forces
Minimal Supersymmetric SM
develop new theories, e.g. Supersymmety ?
Simplest super-symmetric model has 105 dials …
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The Experiment
Smash things together and see what happens!
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How to produce particles at LHC?
Proton Collision
u
d
u
d
u
d
Proton
d
d
u
u
d
b
u
d
b
u
d
Proton
d
Higgs, X, Y …
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d
u
b
b
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Higgs Hunt ?
How do you find one Higgs?
If each person is one collision
event you need to search ~100
times the number of people on
Earth
In 2017 there are 7.5 billion
people on Earth!
Because you need several Higgs
and you will miss some you need to
do this over an over.
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Mont Blanc
LHCThe
at CERN
Higgs Mechanism
Airport
CMS
CERN
LHC control room
http://www.lhc-closer.es/1/3/10/0
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LHC Storage Ring
LINAC
Magnet
Need injector, since magnetic field
cannot start from zero.
RF
Beam broken up into bunches
~ 3000 bunches in LHC
~ 100 billion protons/bunch
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The LHC Protons
The bottle with hydrogen gas (the protons)
~ 12 liters of gas compressed
(1 gram of gas)
Airport
CERN
How often does it need to be refilled?
In a year
8 months/year
x
120 fills/month
~ 3 *10 17 protons / year
x 3 *1014 protons/fill
In the bottle are ~6 *1023 protons
The bottle lasts for 2 Million years !
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LHC RF Cavity
Acceleration to full energy takes 20 minutes.
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PS Accelerator Section
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LHC in LEP tunnel
LHC
Superconducting magnets:
• 1232 dipole magnets (bending)
- T = -271oC (superfluid Helium)
- 100,000 x earth magnetic field
superconducting dipole magnet
Each beam
• Circulation time: 89 s
• Current: ~ 0.6 Ampere
• Time between collisions: 25 ns
• Fill time (450 GeV):
7.5 min
• Acceleration time : 20 min
• Beam lifetime
: several hours
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Beam Protection
Energy stored/beam:
360 MJ
Energy stored in magnets: 700 GJ
• The energy per proton is equivalent to using ~70,000 Hiroshima
bombs (‘Little Boy’) to accelerate a 22 caliber bullet.
• The energy stored in the beam is equivalent to a small aircraft carrier
of mass 10,000 tons traveling at 20 miles/hour.
• This energy can lighten up a 100W light bulb for 1000 hours.
Beam loss is fatal:
copper plate
450 GeV beam
10 20
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40 bunches
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Develop Diamond Detectors
Prototype diamond pixel detector
readout at UTK (SERF)
using radioactive sources
Installation of diamond diode detectors
near the beam pipe in the CMS detector
to continuously monitor the beams in the
CMS detector region
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How to detect the Higgs?
Every 25ns protons in bunches collide
Interactions/crossing = 25 (~1000 charged particles)
Simulation
in 100,000x earth magnetic field
Higgs + 25 other events
+
-
p Higgs
+
p
Z
-
In CMS collision information corresponds to 100 billion phone calls per second.
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The LHC Collaboration
About 10,000 of Earth’s inhabitants
came together to make it happen.
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The CMS Detector
Superconducting coil
-270oC
Charged Particle
Tracker
Photon and
Electron Detector
Width:
22m
Diameter: 15m
Weight: 13,000 tons
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Muon Detectors
Iron return yoke
Weighs ~25%
more
than
the Eiffel Tower in Paris
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The Big
Bang Machine
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The first force studied carefully by CMS was Gravity …
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The CMS Collaboration
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The CMS Detector
Superconducting Solenoid
Hadron Calorimeter
[scintillators & brass]
E/M Calorimeter
All Silicon Tracker
(Pixels and Microstrips)
Muon System
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PLT
New detector to measure
precisely the interaction rate
close to LHC beam
Grant – UTK GradStudent at CERN
Collaboration between UTK
Princeton, Rutgers, Wisconsin Vanderbilt, CERN, Fermilab
Successful measurements since 2015
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Higgs
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But we have only just started to
understand the Higgs boson…
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we need to look from every angle as
there might be something unexpected!
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The full picture
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The larger picture …
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Probing Gravity
Simulation of a black hole
event with in CMS
Strength of Forces
3-2-1
LED
al
on
nti
ty
avi
r
G
nve
o
C
(1 mm)–1 1/R M*
1 TeV
MPlanck
N. Arkani‐Hamed, S. Dimopoulos, G. Dvali (1998). "The Hierarchy problem and new dimensions at a millimeter". Physics Letters B429 : 263–272
25 February 2017
No signal in direct searches …
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The End
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