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In this issue:
From the Director: An Exciting Juncture for High Energy Physics
Word of the Week: Annihilation
Fall Back This Weekend
Archives Month Contest Ends Today
LCLS Hardware Update

SLAC Today

Friday - October 31, 2008

(Photo - Persis Drell)

From the Director: An Exciting Juncture for High Energy Physics

This week SLAC National Accelerator Laboratory has been host to some of the world's top particle physicists, meeting to celebrate past landmarks, collaborate in current projects and plan future approaches in high-energy physics. This week's B-Factory Symposium and meetings of the BaBar Collaboration and International Committee for Future Accelerators come at an exciting juncture for HEP, as the field celebrates outstanding science supporting the Standard Model, and stretches to seek new physics in the next energy frontier.

Monday's B-Factory Symposium recognized the achievements of PEP-II and BaBar, and also looked forward to the future of heavy flavor physics. SLAC's B Factory was successful in many arenas. It was a wonderfully successful model of how to make an international collaboration work. It was outstanding as an accelerator project, with the PEP-II machine achieving design parameters with unheard of rapidity and then pushing forward to performance goals often exceeding the design specifications by a factor of three. But most of all, the B Factory was successful in delivering the science. Our understanding of the heavy quark and lepton sector of the Standard Model is much deeper than it was a decade ago. The precision of the tests of our understanding is truly impressive. The speed with which the accomplishments of the B Factories were recognized by the Nobel committee is an indication of the significance of the achievement.  Read more...

Word of the Week:
Annihilation


This Feynman diagram shows a positron and an electron (left) colliding to form two virtual photons, which then produce two quark-antiquark pairs (right).

Annihilation, which literally means "to make into nothing," is a term used in physics to denote a process that happens when a subatomic particle collides with its antiparticle. Such collisions result in the obliteration of both particles into a cloud of pure energy. The cloud of energy produced when they annihilate goes on to coalesce into new particles, anything from massless photons to heavy exotic particles, depending on the energy of the particles at the time of the collision.

Collisions of this sort are a foundation of high energy physics research. For example, the SLAC B Factory's PEP-II storage ring collided electrons with their antiparticles, positrons, to examine the resulting shower of exotic subatomic particles.

Fall Back This Weekend

Don't forget to set your clocks back one hour this weekend. Daylight savings time ends in the U.S. this Sunday, November 2 at 2:00 a.m.—later in the year than the pre-2007 changeover, due to an expansion of daylight savings time established by Congress in the Energy Policy Act of 2005.

Archives Month Contest Ends Today

Today is the final day to bring items to the lab Library for the archives month contest. Bring the greatest number of needed issues of SLAC periodicals, including SLAC News, Beam Line, The Interaction Point (TIP), SSRL Users Newsletter, Computing @ SLAC and others to win. See "Celebrate American Archives Month at SLAC and Win!" for the contest rules.

Watch SLAC Today next week for an announcement of the winners.

LCLS Hardware Update


Click for an interactive map of the LCLS.

Highlights this week from the Linac Coherent Light Source hardware installation include:

• All ion pumps and short vacuum breaks are connected in the undulator complex.

• The cast concrete end plug panels are installed at the Beam Transport Hall headhouse.

• The permanently energized dipole magnets are installed in the Beam Dump.

• Certification of the Personnel Protection System from the Beam Transport Hall through to the Beam Dump began this week.

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