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).

by Brad Plummer

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...

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

by My Phuong Le and
Mariangela Lisanti

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 proton–antiproton 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

by Harvey Lynch

(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!

Events

March 24: (4:15 p.m.) SLAC Colloquium: eScience and Semantic Computing

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What is the Matter with the Universe? Telegraph.co.uk
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View online at http://today.slac.stanford.edu/.

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). by Brad Plummer 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...

Catch Me if You Can: Searching for Gluinos at the Tevatron by My Phuong Le and Mariangela Lisanti 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 proton–antiproton 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 by Harvey Lynch 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!	Events March 24: (4:15 p.m.) SLAC Colloquium: eScience and Semantic Computing Access (see all) Pipe rupture impairs fire protection water from Bldg. 730 to IR-6 complex Alpine Gate & PEP Ring Road closed Gates 17 & 30 open 24-7 Research Yard bisected Announcements (see all \| submit) Lab Announcements SLAC Workshop - Retirement Savings Plans: A Refresher Learning & Development Class Offerings - Stanford Campus Symposium to Celebrate Pief Panofsky Community Bulletin Board Register Now for Spring HIP Classes History Channel to Feature LHC - Update Stanford University Faculty and Staff Help Center News (see all \| submit) What is the Matter with the Universe? Telegraph.co.uk Important Hearing on FY 2009 Office of Science Request AIP FYI
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	Thursday - March 20, 2008