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In this issue:
The World's Biggest Catcher's Mitt
Science Today: Catch Me if You Can: Searching for Gluinos at the Tevatron
Save the Date: Saint Lawrence String Quartet Returns

SLAC Today

Thursday - March 20, 2008

The World's Biggest Catcher's Mitt

(From left) Dieter Walz, Ray Arnold, Satyamurthy Polepalle and John Amann, below ground next to SLAC's main beam dump (round tank in the background).

For all the esoteric complexity involved in accelerator-based science, one simple thing remains true with accelerated particles: they must at some point be stopped. Now, a new international collaboration at SLAC is tackling the problem of how to stop powerful beams produced by accelerators of the future.

Currently, electrons from SLAC's linac are stopped using a device called a beam dump, which catches the energetic particles in a swirling bath of water. Although beam dumps come in a variety of designs—passive water-cooled metal plates, drums filled with aluminum beads or just a large tank of water—they all have the same function: stopping a beam of particles and dissipating its energy.

But the more powerful the accelerator, the more energetic the beam to be stopped and the bigger and more complex the beam dump must be for handling its beam. Future accelerator designs, which call for beams up to 20 times as powerful as those produced by SLAC's linac, will require specially designed beam dump systems that can safely handle up to 20 megawatts of power. This complex water-flow dump would have to remove in just a few meters all the beam energy attained from an accelerator several kilometers long.  Read more...

(Daily Column - Science Today)

Catch Me if You Can: Searching for Gluinos
at the Tevatron

One of the most fascinating proposals for new laws of physics that we might discover at higher energies is supersymmetry, the idea that every particle in nature has a partner with the opposite statistics. For every particle carrying a force—for example, the photon or the gluon—there would be a matter particle, and for every matter particle—for example, the quark and the lepton—there would be a particle carrying a new force. In models of supersymmetry, the lightest new particle is often the partner of the photon, called the "bino." This particle is weakly interacting, is not observed by particle physics detectors, and could well make up the cosmic dark matter.

Experiments at the highest-energy accelerator now operating, the Tevatron protonantiproton collider at Fermilab, have made extensive searches for supersymmetric particles. However, the theory of supersymmetry has many free parameters, and current searches cover only a small part of this parameter space. We have been working with Johan Alwall and Jay Wacker here at SLAC to extend the Tevatron results to new regions of the parameters and to construct more robust strategies for finding supersymmetric particles.  Read more...

Save the Date:
Saint Lawrence String Quartet Returns

(Photo - SLSQ)
The Saint Lawrence String Quartet

Once again, the outstanding Saint Lawrence String Quartet (SLSQ) will be coming to SLAC for a noon-time concert.

On Tuesday, April 1, 2008, the SLSQ will appear at the Kavli Auditorium to perform Beethoven's last String Quartet, No. 16 in F major (Opus 135). The concert will begin at 12:10 p.m.

If you know the SLSQ, you know how good this group is, and you certainly will not want to miss the performance. If you do not know the SLSQ and you like fine music and musicianship, you are strongly encouraged to learn about these superb musicians by hearing them live. They are Stanford's resident Quartet, but they also have performed in many venues over the world and recorded several albums.

Please join us!


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