portion of a virtual reality page showing the ATLAS detector construction
The Large Hadron Collider will be starting up on Sept. 10, and the excitement (of physicists at least) is starting to build. Photographer Peter McCready has a set of virtual reality tours of that were taken during the construction phase of the project in case you didn’t get to see it in person.
The start-up will also be broadcast live. You can check it out if you have satellite TV access, the schedule is here.
the yellow spot indicates a bunch of protons arriving after traveling one eighth of the way around the Large Hadron Collider tunnel
Last weekend the Large Hadron Collider was tested by injecting a small number of protons into the beam line and steering them part way around the ring. Another test beam will be sent in the opposite direction on Aug. 22.
I recently spent a week lecturing at a summer school in Zuoz Switzerland. This was finally my chance to stay at a Swiss Boarding School: the Lyceum Alpinum. My lectures were on strong interactions: Quantum Chromodynamics, Seiberg duality, the anti-de Sitter/conformal field theory correspondence and various models like quirks, higgsless, and hidden valleys, There were also lectures on black holes, little Higgs models, and the Large Hadron collider. Slides of all the lectures can be found here.
CERN hasn’t really extended its public relations outreach to include rap videos, but a science writer at CERN, Kate McAlpine, has brought particle physics to the hip-hop masses. The computer voice sounds like, but is not actually, Stephen Hawking.
the path of a charged particle (blue) through the stationary field lines (red) of another charged particle
The winners of the annual Gravity Research Foundation essay competition were announced this week and the top two spots were swept by UC Davis. Steve Carlip won the $5000 first prize for his essay entitled “Symmetries, Horizons, and Black Hole Entropy”, while Nemanja Kaloper and yours truly took second place with How Black Holes Form in High Energy Collisions. We looked at black hole formation following the analogous case of Coulomb scattering. Consider two charged particles colliding with one particle starting out at rest. As we increase the collision energy, the Coulomb field of the moving particle undergoes a relativistic compression, so that at velocities near the speed of light, the field lines are compressed into a shock wave. Away from the shock wave there is essentially no scattering, everything happens as the rest particle crosses the shock wave. The same thing happens in gravitational scattering, and the shock wave metrics for a highly boosted particle are well known. If such a particle is approaching a second particle at rest, the the second particle is a tiny perturbation on the shock wave metric, so the calculation is very simple. Even if the particle at rest crosses the shock wave at a large distance from the fast-moving particle the shock wave can scatter it almost directly towards the fast-moving particle so that they can pass within the Schwarzschild radius of the particle that started at rest.
the path of a charged particle (blue) through the moving field lines (red) of another charged particle
the path of a charged particle (blue) through the very rapidly moving field lines (red) of another charged particle
This week Nathan Seiberg of the Institute for Advanced Studies, Princeton gave the physics colloquium. You have probably heard his name in connection with the Seiberg-Witten theory (which revolutionized areas of both theoretical physics and mathematics), and from Seiberg duality (which gave us a new understanding of strongly coupled field theories). His talk explained the cosmological and particle physics motivations for supersymmetry, and new ideas about how supersymmetry can be broken if the vacuum of spacetime is unstable. You can see copies of his slides here.
Postcard of tracks left by a jet (lower left cluster of pink lines) observed at CDF
The latest installment of the West Coast LHC Meetings was held in Davis last week. The meetings are trying to prepare theorists (particularly those living on or near the West Coast) for the flood of data that will arrive from the Large Hadron Collider (LHC) which will run a test beam in 2007 and start full scale running in 2008. The main focus of the meeting was “jets”. when high energy quarks or gluons are produced in particle collisions they appear in the detector as a large spay of particles (called a jet). Trying to relate the proerties of jets to the properties of the quarks and gluons is a big problem. Most of the talks are available online.
a multi-jet event viewed through energy deposition along thedetector barrel (from Joey Huston's talk)