Category Archives: Public lectures

LHC: unplugged

Tomorrow should be interesting as I’ve been asked to give an informal talk on the LHC to our physics staff and students. I’m looking forward to it as the only rule is no powerpoint, just whiteboard and marker, i.e. unplugged. I’ve been thinking about how to give such a talk for all levels, I’ll think I’ll break it up as

1 WHAT

Particle colliders, new LHC vs old LEP, energy achievable etc.

Reason for vacuum (UHV), reason for low tempT, physics of focusing etc

Description of detectors

2. WHY

Creation of exotic particles (E = mc2), study of fundamental particles

Study of fundamental interactions and  unified field theory

Cosmology: glimpse of early universe, info on matter/antimatter asymmetry, info on dark matter

3. A BRIEF HISTORY OF PARTICLE PHYSICS

The proton and the periodic table

The nuclear model of the atom

The particle zoo and the quark model

Six quarks and six leptons

The Standard Model: fermions and bosons, E-W theory, QCD, the Higgs boson

4. LHC EXPECTATIONS: STANDARD MODEL

Higgs boson, explanation for mass, explanation for matter/antimatter asymmetry

5. MORE THEORY: BEYOND the STANDARD MODEL

Grand Unified Theories

Theories of Everything

Supersymmetry: SUSY breaking, SUSY particles: which model of SUSY?

Neutralinos: candidates for dark matter?

6. LHC EXPECTATIONS: BEYOND the STANDARD MODEL

SUSY particles

Neutralinos

WIMPs

7. SUMMARY

HIGGS: could close chapter on Standard Model

SUSY: could open new chapter in particle physics

SUSY: could explain dark matter

OTHER: extra dimensions? mini-black holes? other surprises? evidence for strings?

***************************************************************

Useful pics I might use are:

II The Standard Model

III. Unified Field Theory

Might finish with this great pic and text from the search for Higgs at FERMILAB

In the Standard Model of particles and forces, the masses of the W boson, the top quark and the Higgs boson are connected. If one knows the mass of any two of the three particles, then the mass of the third particle can be calculated. This plot illustrates that relationship. It depicts the mass of the Higgs boson as a function of top quark and W-boson mass. Each diagonal line represents a single Higgs boson mass; examples chosen are MH = 114, 300 and 1000 GeV/c2. Based on theoretical constraints and direct experimental searches, scientists expect the mass of the Higgs boson to lie somewhere in the green-banded region. The new CDF measurement of the W-boson mass (see this press release) indicates that the W-boson mass is heavier than previously measured (worldwide average). Since the top quark mass did not change, a heavier W-boson mass indicates a lighter Higgs Boson. The blue ellipse shows the most likely values for the top quark and W-boson masses, based on all available experimental information, including the CDF result, at the 68 percent confidence level. The intersection of this ellipse with the green band indicates the most likely Higgs boson mass. This result can be compared to an older result (red ellipse), which did little to constrain the Higgs boson mass. Credit: Fermi Lab

**************************************************

Update: Phew, that’s over. I now appreciate slides, powerpoint etc – definitely harder to keep the story linear on the blackboard. I went way overtime which is not like me. Still, it’s great to have an educated audience. Good questions afterwards – and nobody mentioned earth-eating Black Holes.

Now I’m off to the mountains of Mourne for a hill-walking weekend with GLENWALK, the well-known walking club with a  drinking problem…yipee

Update II: A few people have asked me for a hardcopy of the talk. I’ll try and knock something up and stick on the My Seminars page of the blog, but it’ll take some time as I used the whiteboard on the day. I’m giving a simpler talk on the same subject to schools on 12th october for Maths Week 2008, will definitely prepare a powerpoint presentation for that ..

3 Comments

Filed under Particle physics, Public lectures