PX434 – Physics of the Standard Model
Dr Steven Boyd : P448
ATLAS Event Display
Intro Stuff
Lectures are divided in chapters – each chapter has a
writeup which will be put online
There is a module homepage
http://www.warwick.ac.uk/fac/sci/physics/teach/module_home/px434/
Books:
D. Griffiths,Introduction to Elementary Particles,
Prentice-Hall
D. Perkins, Introduction to High Energy Physics
R. Feynman, Lectures on Physics Vol II
F. Halzen and A.D.Martin, Quarks and Leptons
Griffiths is the main text, supplemented by Perkins. Halzen and
Martin is quite technical, and somewhat out of date for material
from the last 10-15 years
Recommended Text
Course Overview
History of Particle Physics : Beginning Lecture
Chapter 1 : Introduction and Preliminaries : Standard Model, Feynman Diagrams,
Conservations Laws and Symmetries, Units and Relativistic Kinematics, Decay
rates and Cross sections, Group Theory
Chapter 2 : Quantum Electrodynamics : Bosons and Fermions, The Klein-Gordon
and Dirac Equations, Spinors, Feynman diagrams, Electron-Muon Scattering
Chapter 3 : The Strong Interaction : Isospin, Strangeness, The eight-fold way,
Quark theory and evidence for quarks, evidence for colour, QCD, Confinement and
asymptotic freedom
Chapter 4 : The Weak Interaction : Weak and Neutral currents, Parity violation and
the V-A current, Cabibbo theory and the GIM mechanism, Kaon oscillations, CP
violation
Chapter 5 : Pulling it all together – the Standard Model : The Weak coupling,
Electroweak unification, Weinberg angle, Z0 decay
Chapter 6 : Spontaneous Symmetry breaking and the Higgs : Mass in the
Standard Model, Spontaneous Symmetry Breaking, The Higgs potential, Higgs
mass and the LHC
Chapter 7 : Beyond the Standard Model : Problem with the Standard Model,
Grand Unification, Unanswered Questions, Where to go from here
Including an examples class after every chapter
A brief history of particle physics
6-5 Century BC
Concept of the atom developed by Democritus
and several ancient schools of early Hindu philosophy
in India.
1709-1899
Discovery of electrons – ending with JJ Thompson and
the plum pudding model of the atom
1917-1919
Discovery of protons by Rutherford with his famous
gold foil experiment
A Brief History of Particle Physics
1930's
Neutron (after 1932)
Neutrino (proposed, but not seen
until 1956)
Photon
1932
Positron, predicted by Dirac,
discovered byAnderson
Neutron discovered by Chadwick
Pions and Muons
1935
Yukawa suggested that the nuclear
force was due to the exchange of
particles (mesons)
1937
Muon discovered, prompting Rabi to say
“Who ordered that” at a major conference
1946
Charged pion discovered, and
found to decay to muons
Neutral pion discovered
QED
1950
Feynman, Schwinger and Tomonaga synthesised a
coherent theory of electron-photon interactions from
early quantum mechanics. This is called Quantum
Electrodynamics
Strangeness
1946 : particle physics understood. Nothing really new to
discover
1947 : Kaon discovered, followed by the Lambda. These
new particles were tagged as “strange” particles
Produced in strong interaction
but decay via weak interaction
Always produced in pairs :
Gell-Mann and Nishijima
propose a new conserved
quantum number : Strangeness
The Particle Zoo
1950's – 1970's : Bewildering array of new particles
discovered. Physicists begin to despair about understanding
flood of new particles.
The Eight-Fold Way
1961 : Murray Gell-Mann fits all the known particles into
simple frameworks. Later it turns out that these structures
are predicted from group theory and the proposition of
quarks
Quarks
1964 : Why is the eight-fold way successful? Gell-Mann
and Zweig propose that all known particles made up of
quarks and anti-quarks which he imagines as localised
quantum numbers, but not localised particles
Noone believes them to be anything other than an
accounting trick until 1974.
1964 : Brout, Englert, Guralnik, Hagen, Kibble and Higgs
propose a mechanism by which particles attain mass.
This is tested, off and on, for the next 45 years.
1974 : Discovery of the charm quark in the J/Ψ – this
validates the quark model and cements quarks as “real”
particles.
QCD
1970's : a theory of the strong
interaction is devised by
Gell-Mann and Feynman called
Quantum Chromodynamics
involving a new
quantum number called colour.
1970's : improved understanding of the weak interaction
allows Salam, Glashow and Weinberg to unify it with
the EM interaction to create the “Electroweak” Interaction
More particles
1973 : Neutral Current interactions
are discovered
1975 : the tau lepton is detected at SLAC
1978 : the bottom quark is detected at Fermilab
1979 : the gluon – the colour force carrier is discovered
at DESY
More particles
1983 : the W±/Z0 - the electroweak force carriers are
measured at CERN by UA1 and UA2
1995 : the top quark is (finally) discovered at Fermilab
with a mass of 172 GeV.
Up-to-date
1998 – Now : Neutrinos are shown to be massive through
neutrino flavour oscillations (see PX435)
Two months ago : a Higgs-type thing is discovered.
What next?
Goal
The goal of this course is to discuss the
physics behind the Standard Model.
We will not, explicitly, write the entire Model
down as, although doing so can give us
some insights, it requires a bit of
background.
If you want to see the model, take the Gauge
Theories and the Neutrinos course next term.
We will look at the physics of each of main
forces in turn, and try to outline experimental
evidence for their current formulation
The Standard Model
Quantum Electrodynamics
The Strong Force and Quantum
Chromodynamics
The Weak force
Spontaneous Symmetry breaking and the
Higgs Field.
Goal
The goal of this course is to discuss the
physics behind the Standard Model.
We will not, explicitly, write the entire Model
down as, although doing so can give us
some insights, it requires a bit of
background.
If you want to see the model, take the Gauge
Theories and the Neutrinos course next term.
We will look at the physics of each of main
forces in turn, and try to outline experimental
evidence for their current formulation
Quantum Electrodynamics
The Strong Force and Quantum
Chromodynamics
The Weak force
Spontaneous Symmetry breaking and the
Higgs Field.