Friday, April 08, 2005

Pierre Auger Observatory

In his excellent paper, Louis LePrince-Ringuet, citing a remark of Powell's at the Conference of Bagneres-de-Bigorre in 1953, declared that from that date on, particle accelerators took the place of cosmic rays, which more or less faded into the background. And yet, even today accelerators have not caught up with cosmic rays.

Pierre Auger on Cosmic Rays

"For in 1938, I showed the presence in primary cosmic rays of particles of a million Gigavolts -- a million times more energetic than accelerators of that day could produce. Even now, when accelerators have far surpassed the Gigavolt mark, they still have not attained the energy of 1020eV, the highest observed energy for cosmic rays. Thus, cosmic rays have not been dethroned as far as energy goes, and the study of cosmic rays has a bright future, if only to learn where these particles come from and how they are accelerated. You know that Fermi made a very interesting proposal that particles are progressively accelerated by bouncing off moving magnetic fields, gaining a little energy each time. In this way, given a certain number of "kicks," one could perhaps account for particles of 1018 -- 1020 electron volts. As yet, however, we have no good theory to explain the production of the very-high-energy particles that make the air showers that my students and I discovered in 1938 at Jean Perrin's laboratory on a ridge of the Jungfrau."
-- Pierre Auger, Journal de Physique, 43, 12, 1982

On the vast plain known as Pampa Amarilla in western Argentina, a new window on the universe is taking shape. There the Pierre Auger Cosmic Ray Observatory has begun its study of the universe's highest energy particles. These rare messengers should tell an important story about how they originate. Experiments have so far failed to decipher their message, and their existence has become a profound puzzle. The Auger Observatory is attacking this enigma of the highest energy cosmic rays with unprecedented collecting power and experimental controls.

John Ellis:
The next step will again be taken in Japan, with the new J-PARC accelerator starting in 2009 to send neutrinos almost 300 km, again to the Super-Kamiokande experiment, to probe the third neutrino mixing angle that has not yet been detected in either atmospheric or solar neutrino experiments. This may also be probed in a new experiment being proposed for the Fermilab NuMI beam. One of the ideas proposed at CERN is to probe this angle with an underwater experiment moored in the Gulf of Taranto off the coast of Italy, viewing neutrinos in a modified version of CERN's current Gran Sasso beam.

Aussois, Savoie, France
After "Neutrino 2004" the convergence of results from atmospheric, solar, reactor and accelerator experiments confirms the massive neutrino and gives the first opportunity to test physics beyond the Standard Model. The neutrino oscillations picture is still missing 3 fundamental ingredients: the mixing angle θ13, the mass pattern and the CP phase δ.

Future neutrino beams of conventional and novel design aimed at a megaton type detector could give access to these parameters. Such a detector would also be the next generation facility for proton decay searches and an invaluable supernovae neutrino observatory.

To understand the Higgs mechanism, imagine that a room full of physicists chattering quietly is like space filled with the Higgs field ...

So who is the professor that crosses the room? It is Albert Einstein:)

Any such Blackhole would quickly decay into a shower of Hawking radiation (mainly into standard model particles on our brane, rather than into grvaitons into the bulk). This shower of radiation would be quite different from showers arising from, say, the collsion of cosmic-ray proton with a atmospheric atomic nucleus. Gravity is "flavor blind," so when a microscopic blackhole evaporates it produces all the Standard Model particles with equal probability. Once one accounts for spin and color, it turns out that particles produced when a blackhole decays are about 72 percent quarks and Gluons, 18 percent leptons, and the rest are bosons. Such a distinctive shower of particles would be hard to miss. So there is the possibility that the Pierre Auger Observatory will detect blackholes.
Page 262, Out of this World, by Stephen Webb

Two of the tanks in the Pierre Auger Observatory are shown. They each hold 12 tonnes of clean water and are viewed by 3 X 8” diameter photomultipliers. The electronics for recording and data transmission are powered by solar cells. These tanks are placed close together so that cross-tank measurements of densities and arrival times can be made but the nearest neighbour for all other tanks is 1.5 km away. In this way 3000 km2 can be covered with only 1600 detectors.

1 comment:

  1. Anonymous11:33 AM

    Thanks!! I think Ill return in the near future