PHYS 400/506 -- Some Suggested Topics for your Seminar
Remember, you are encouraged to come up with a topic of your choice not
mentioned on this list... This list is to give you just a few ideas
of potentially interesting topics. Or you may want to make your own
variation of one the suggested topics below.
For the topics of a historical nature, many
excellent references may be found in campus libraries. I can provide
some help with locating journal articles on specific experiments mentioned.
Want to browse for ideas? Get a current list of articles on
Subatomic Physics and related topics from:
Scientific American ,
Physics Today ,
New Scientist ,
from the SPIRES database.
These journals, and most academic physics journals,
are available in several libraries on campus,
including the Main Library, TRIUMF, and many of these journals are
available online as
Journals accessible to you from any on-campus site (....ubc.ca) thanks
to the UBC Library's sitewide licenses.
- The Big Bang
- The highest energies reached at man-made
accelerators is presently in the 2x10**5 GeV range,
while energies of about 10**19 GeV were real just after
the Big Bang. Review the basic stages of the universe from
about 10**-45 sec after the Big Bang, to the present
time ( approx. 10**17 sec). Steven Weinberg's book, The
First Three Minutes, is an excellent reference for this topic.
- Baryon Asymmetry of the Universe
- We still don't
know why matter dominates over anti-matter in our universe... Many
models assume that the universe began in
a symmetric state with zero overall baryon number, and
introducing a large baryon asymmetry is not a simple task.
Review some of the physical processes which may introduce
such an asymmetry and discuss the implications.
- Dark Matter
- Astronomical observations of the motion of
galaxies and interstellar gases suggest that most of our universe
composed of dark matter, that is matter which we don't
see. Review the astronomical evidence that
infers the existence of dark matter, and discuss possible
particle physics (and other) candidates for dark matter.
- Grand Unification
- It is speculated that the four forces
of nature are all related and hence can be unified at some
large mass scale. Explain the running of the coupling constants
of these forces and discuss some candidates for a GUT theory.
String theory and M-theory are currently hot topics in this field.
- What is it? How does it relate to the
Standard Model? What kind of expectations do we have for
discovering supersymmetric particles? Many experiments have
conducted fruitless searches for SUSY particles. Describe and review
an analysis and results of a SUSY search conducted by one of the
LEP experiments, or some other recent experiment.
- Neutrino mass
- Several experiments have
performed to measurements of the neutrino mass by examining the
endpoint of the electron spectrum in beta decay.
Explain the types of experiments and experimental techniques used
(for example, you might want to show examples of and
describe what a Kurie plot is)
- Solar Neutrinos
- Several recent experiments have
neutrino flux from the sun and find that it appears to fall
short of predictions of a standard solar model. Briefly describe the
solar model and its predictions and review some recent
experimental results. Most notably, the Super Kamiokande
experiment, in an
underground mine in Japan observes a discrepancy in the standard
solar model. The Sudbury Neutrino Observatory
(SNO) in Ontario started taking data this year and has already
detected solar neutrinos. Describe either one of these
- Magnetic Monopoles
- What are they?
Can they fit into the electromagnetic theory of Maxwell?
What experimental techniques have been used to search for
them, and what are the results of these experiments?
- J.J.Thompson's theoretical and
experimental work in which he discovered the
- Describe Thompson's Nobel Prize winning work, and
describe the apparatus and the experiment he performed and
how he was able to deduce that he had discovered a new particle, the
- Rutherford's scattering experiment
- Describe Rutherford's
Nobel Prize winning work on the structure of the atom, including
his famous Coulomb-scattering experiment in which
he showed that most of the mass of an atom is concentrated in a tiny
nucleus at the center of the atom - describe with
examples his prediction and experimental results for cross-section as
a function of incoming alpha particle angle.
- The discovery of parity violation
- What is parity violation?
- explain Yang and Lee's postulate that parity is violated,
based on deductions from observations in nonleptonic kaon
decays. (This work won them a Nobel Prize) Describe the beta decay
experiment using polarized cobalt of C.S. Wu, in which she discovered
- Confirmation of 3 and only 3 generations of massless
- Review the experimental and
theoretical limitations on the
number of generations in the Standard Model.
Describe the experiment which was first performed at the SLAC
linear collider, (later confirmed and measured to extremely
high precision at the LEP accelerator at CERN ) in
which it was established that there are three and only three
similar generations with Standard Model massless neutrinos.
- Ernest Lawrence proposed the idea of a magnetic
resonance accelerator (the cyclotron), and in the 1930's he and a
graduate student, Stanley Livingston built and operated the first
cyclotron. (It won Lawrence a Nobel Prize) Describe their apparatus
and explain how it was used to
accelerate protons to 1.2MeV. A modern synchrotron, such as
the one at TRIUMF, is based on a principle similar to that of the
cyclotron, except that the magnetic bending field, B and
the RF frequency must increase and be synchronized with the particle
velocity as it increases. Outline briefly how the TRIUMF synchrotron
(or any particle accelerator of your choice) works.
- The parton model -- structure of the proton
- Describe the parton
model and and its confirmation in deep-inelastic electron-proton
scattering experiments, which showed that there are quasi-free
point-like constituents, which we
now call quarks, in the proton (and all nucleons). Describe the deep
scattering experiment performed at the Stanford
Linear Accelerator Center which provided evidence for the
existence of quarks and won a Nobel prize
for Canadian Dick Taylor and his colleagues Kendall and Friedman.
- Quarkonium - quark-antiquark bound states
- QCD Potential
- discuss the standard Coulomb plus linear
potential often used to model and solve QCD bound state problems..
Compare the energy levels of a heavy (c or b ) quarkonium system
(to those of the
positronium system (bound e+ e- state), emphasizing similarities
- QCD (Quantum ChromoDynamics)
- What is a gluon and
what is its role in the non-Abelian gauge theory of QCD?
Evidence for quarks radiating a hard gluon was first
observed at the PETRA storage ring in Germany -
Discuss and explain the experimental signature seen at the PETRA
experiments at the DESY laboratory in which the gluon was
- QED (Quantum ElectroDynamics)
- QED is an Abelian gauge
theory. Feynman, Dyson,
Tomonaga and Schwinger developed the theory of QED in the
late 40's. Perhaps
the most precise tests in physics have been in testing
the predictions of QED. Describe the
theory and some of the extremely high precision tests.
- CP-violation in the K system
- Describe the famous
Nobel-prize winning experiment of
Christenson, Cronin and Fitch in which they studied
2 pi and 3 pi K0 decays and discovered CP-violation.
- how does this CP-violation fit into the Standard Model and
the Kobayashi-Maskawa quark mixing scheme?
- The W and Z Bosons, the intermediate vector bosons of the Standard
- What are they? Describe how they were discovered
at CERN's SPPS proton-antiproton collider, in particularly clean
leptonic decay channels in the 1980's. The development of
stochastic cooling for the antiproton beam and the subsequent
discovery of the W and Z bosons won a Nobel prize for Simon van der
Meer and Carlo Rubbia.
- Semileptonic decays of heavy quarks
- Non-hadronic decays of heavy
quarks have recently contributed much to our understanding
of the Standard Model, in particular in deducing
the elements of the Kobayashi-Maskawa mixing matrix, and
understanding the interplay between the weak (exactly
calculable) and QCD (hard to calculate) contributions in weak
decays of bound quarks. Review the physics of the weak force
in heavy quark decay and how KM matrix parameters may be deduced
from the study of heavy quark decays
- Kobayashi-Maskawa-like mixing in the lepton sector
- While not in
the Standard Model, it is possible that there is mixing in the
lepton sector. What implications
does this have on neutrino oscillations and neutrino masses?
Several experiments have placed limits on neutrino masses from
the non-observation of muon neutrino to tau neutrino oscillations,
most notably the E531 emulsion experiment at Fermilab, which ran in
the early 1980's, and two
just recently started experiments at CERN: NOMAD and CHORUS.
Describe the apparatus and techniques used to measure neutrino mixing
limits from any one or more of these 3 experiments.
Recently an underground water experiment, SuperKamiokande, has
seen experimental evidence that neutrinos may indeed have non-zero
mass. Review this experiment and its results and implications.
- e+ e- --> Z0 reactions to determine sin**2 (theta_W), the
weak mixing angle
- Describe how the width, mass and cross-section
of the Z0 in e+e- annihilation and the constraints of the
Standard Model may be used to deduce sin**2 (theta_W),
a fundamental parameter in the Model. There are
four experiments presently running at the e+e- LEP accelerator
at CERN which have measured these Z0 parameters to extreme
- CP-violation in the B system
- Several B-factorys
are presently under construction at several labs around the world.
They aim to examine CP-violation
in the heavy b quark system, providing complimentary information
to what we know about CP-violation from kaon decays. The
B factory studies will provide very stringent restrictions
on or disprove(!!) the Standard Model. Describe the
physics of the CP-violation in the B system, and review some of the
techniques presently being studied
to observe CP-violation in the B system at one of the
experiments (BELLE at KEK, BaBar at SLAC, BTeV at Fermilab,
HERA-B at DESY, CLEO at Cornell)
- The LHC - Accelerator and the physics challenges
The Higgs boson may be discovered at the LHC,
(the Large Hadron Collider) at CERN, in Switzerland in about a
decade, or some wildly new unanticipated physics may turn up
there. Describe the basic specifications of the LHC
and review some of the search strategies currently being studied
which might lead to the discovery of the Higgs boson(s).
- Nuclear Fission
- How does a nuclear reactor work?
How does an atomic bomb work? Maybe you can tell us how to make one, or
review the early attempts and history at Los Alamos in developing the
- Nuclear Fusion
- What is fusion? Describe the evolution
of stars and the role of nuclear fusion and the chain of
nuclear reactions in stellar evolution, or H-bombs.
- Drift Chambers
- How do you make one? how does it work?
How are they used to precisely measure momentum
of the charged particles
electron, muon, pion, kaon, and proton
Describe how measuring specific ionization (energy deposition per
unit length traversed in a gas, often referred to as dE/dx) may be
useful in identifying the 5 above mentioned particle species.
Georges Charpak won the Nobel Prize for his invention and
development of wire chambers
- What is a calorimeter and how does it
work? Choose one or more of the modern types
calorimeters used for either electromagnetic or hadron calorimetry
in particle physics (liquid argon, lead glass blocks, BGO, CsI or NaI
proportional-tube iron sandwich.... ) and review how it works and
describe the performance in any experiment of your choice.
- Silicon Microvertex Detectors
- Recently very high
precision tracking (10-20 microns spatial resolution
is typical) has been achieved with silicon wafer detectors
positioned very near the interaction vertex. Explain the
operational physics of a typical silicon vertex detector and discuss
some examples of physics where such detectors are extremely valuable.
- Fermi and the development of weak decay theory
In the 1930's, Enrico Fermi developed the ß-decay theory, coalescing
previous work on radiation theory with Pauli's idea of the neutrino.
Following the discovery by
Curie and Joliot of artificial radioactivity, he demonstrated that
nuclear transformation occurs in almost every element subjected to neutron
bombardment. He won the Nobel Prize for this work. His PhD thesis is a
fabulous 2 page wonder.
- Renormalizability of the Standard Model
- Just last
year, t'Hooft and Veltman won the Nobel
Prize for their work 2 decades ago, showing that the non-Abelian gauge
theory of the Standard Model is indeed renormalizable. An interesting
ingredient of this work is the yet-to-be-discovered Higgs particle.
- Particle Identification Detectors
- Recently, several
new types of particle detectors have been developed which aid in
identifying particle species. Some of the newer types are based
on imaging Cerenkov light emitted by a particle traversing a tank of
liquid, as the particle is travelling faster than the speed of light
in that liquid. (These detectors are called RICH's or CRIDs or DIRCS for
Cerenkov Ring Imaging Detector and variations thereof.) Describe
one such operating detector and explain how it works and why it is
- String Theory
- Are the real fundamental "particles" of
our universe actually 1 dimensional strings, rather than 0-dimensional
point-like objects? All the various particles we observe arise in
string theory as
excitations of a string. Included in the theory is the graviton, the
boson mediating the gravitational force, so String Theories would
incorporate all 4 fundamental forces, rather than 3 only in the
Resources and relevant Electronic Journals and Magazines
Return to PHYS 400/506 Homepage
Janis McKenna, UBC Department of Physics, August 2000