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In this issue:
Rolling the Event Dice
SLAC Researchers Discuss Physical Sciences in Popular Blog
First Set of Kids Day Photos Now Online
Stanford Benefits Offers Medical Plan Subsidy

SLAC Today

Friday - August 24, 2007

Johan Alwall using MadGraph/MadEvent.
(Click on image for larger version.)

Rolling the Event Dice

When the Large Hadron Collider (LHC) begins experiments next year, particles will collide 40 million times per second. From these collisions, computers must choose 200 of the most "interesting" events to record—only .0005 percent—which may lead to new discoveries. Johan Alwall, a postdoc at SLAC in theoretical high-energy physics, recently helped develop a powerful new version of MadGraph/MadEvent, a software program that helps scientists determine which data is most "interesting."

MadGraph/MadEvent creates random, aptly named Monte Carlo events that scientists practice with before taking real data, and has significantly evolved over the past several years. In 1994, a program called MadGraph had the ability to generate complex physics equations for theorists. Eight years later, the program incorporated MadEvent, which uses the generated equations to create simulations. Now, the new version has expanded, allowing scientists to generate events based on new theories.

"This release is really exciting since we're implementing many useful, new features," said Alwall.

One feature allows scientists to easily study models of the universe other than the widely accepted Standard Model, such as supersymmetry. Previously, new theories required pages of extremely complicated equations to generate events. Scientists now can input an event's specific characteristics—which known or new particles to create, how they interact with each other, and the strength of these interactions—and the program starts generating events.

"The new program is completely automatic," said Alwall. "It makes it much more difficult for scientists to make mistakes."

SLAC Researchers Discuss Physical Sciences in Popular Blog

Cosmic Variance bloggers Risa Wechsler (left) and JoAnne Hewett.

Since the inception of blogs in the mid-1990s, the medium has exploded into mainstream arena. The web's most popular blog,, receives 360,000 visits every day. Blogs come in all shapes and sizes—big, small, serious and silly—but all have the same goal; to be read. One blog about the physical sciences,, has succeeded. And two SLAC physicists, JoAnne Hewett and Risa Wechsler, regularly contribute to its pages.

Cosmic Variance began two years ago when experienced physics bloggers Sean Carroll and Mark Trodden approached Hewett and Wechsler with a proposition; join forces in one group blog by a bunch of physicists. Both agreed, and Wechsler helped Carroll design and set-up today's most popular physical science blog. Averaging 4,000 readers per day, Cosmic Variance was the fourth most popular blog in any science field last year, according to Science magazine.

"We attract a large following both inside and outside the physics community," said Wechsler, a theoretical cosmologist at SLAC. "But we write with the general public in mind."

Seven particle physicists and astrophysicists contribute to the website, which ensures new posts appear almost daily and that no one writer ever feels obligated to post when his or her life becomes hectic.  Read more...

First Set of Kids Day Photos Now Online

Click on image to see more photos.

This year's Kids Day was a tremendous success, with more than 240 kids in attendance. A selection of Kids Day photos is now available online, thanks to SLAC photographer Diana Rogers.
View the first set of photos...
View the second set...

Stanford Benefits Offers Medical Plan Subsidy

In 2008, Stanford will once again provide a program to subsidize the medical plan contribution for SLAC employees who fall under a certain income level.

The Medical Contribution Assistance Program (MCAP), which lowers the amount an employee pays to cover his or her dependents under a medical plan, is available to employees with a combined Adjusted Gross Income on their most recent Federal income tax return of $60,000 or less. In mid-September, the Stanford Benefits Office will mail a letter that includes the application and a cover letter explaining the program to all employees who fall into this approximate salary range. Applications are due on October 5, 2007.

"Last year we had 500 applicants. Of those, 473 qualified—with over half receiving the full subsidy," said Stanford Benefits Communications Manager Robbie DeBastiani. "I highly recommend that qualified applicants apply."

For further information, please contact the SLAC Benefits Office at (650) 926-2356. Also available in the SLAC Benefits Office are MCAP applications in English and Spanish.

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