Thursday - April 27, 2006

GLAST's Large Area Telescope will view the universe in gamma ray photons, allowing researchers to create images like the simulated one shown above. In order to create these maps accurately, the telescope will need to be well-calibrated.

GLAST Telescope Components
to be Tested at CERN

by Chandra Shekhar

When the task is to find gamma ray photons in outer space, where they are outnumbered 10,000 to 1 by charged particles, it helps to have a perfectly calibrated instrument.

The instrument charged with this challenging task is the Large Area Telescope (LAT), assembled at SLAC as part of the NASA-led multi-nation Gamma-ray Large Area Space Telescope (GLAST) project. As the LAT gets ready to go to the Naval Research Laboratory for further environmental testing, a scaled-down version of it, called a calibration unit, will undergo several weeks of testing at CERN from the end of July through mid-September.  Read more...

The Rarest B Decay

by Jeffrey Wayne, BaBar

SLAC's BaBar detector.
(Photo by Peter Ginter.)

As the PEP-II accelerator creates ever increasing numbers of electron-positron collisions, BaBar experimenters are exploiting the large data sample to search for exceedingly rare particle reactions which could potentially reveal the existence of new spacetime dimensions and symmetries.

In a paper recently submitted to Physical Review, BaBar researchers describe the latest measurements of the rarest B meson reaction ever observed: a B meson decaying into a K meson and a pair of charged leptons (electrons or muons). The B meson, which is composed of a "bottom" quark and a light anti-quark, is prolifically produced by PEP-II, and out of the 500 million B mesons recorded by the BaBar detector, only 50 of these rare decay events were found.

BaBar researchers relied on excellent particle identification by the detector, multivariate background discrimination methods, a "blind" analysis technique, and plenty of data to accomplish this needle-in-a-haystack feat.

The motivation for their search was to study how a bottom species of quark can change into a "strange" quark species, which in the Standard Model theory can only proceed via a rare "penguin diagram" loop of virtual high-energy particles. New dimensions of spacetime, or new spacetime symmetries, such as supersymmetry, could dramatically modify this prediction, changing the decay rate or the angular orientation of the decay products. The standard theory was found to be consistent with the BaBar results, which highly constrains how supersymmetry or extra dimensions could be realized in nature. However, with only small samples currently in hand, there is plenty of room for even stronger tests of these new phenomena as BaBar plans to accumulate billions of B mesons through 2008.

Planned Isobutane Flare

by Judy Fulton

(Click on image for larger version.)

SLAC is making way for LCLS construction. Part of this effort is the removal of a 30-foot isobutane tank located on the SLAC Large Detector gas pad near Building 750. Isobutane is a flammable gas that must be managed in a safe manner to prevent a fire hazard or even an explosion.

Working with HAAS- TCM, SLAC's chemical service provider, and two sub-contractors that specialize in this type of work, Chemical and General Safety (CGS) and Conventional and Experimental Facilities (CEF) have partnered to remove this tank. The first step was burning off any remaining Isobutane using a torch placed a safe distance away from the tank and any combustible material.

The tank will now be purged multiple times using an inert gas and then filled with water. After the tank is empty and clean it will be sent off site to a metal recycler.

Linear Collider Industrial Forum Comes to SLAC

By Albe Larsen

The Linear Collider Forum of America (LCFOA) will hold its Spring 2006 meeting at SLAC on May 1-2. The LCFOA is an organization of manufacturers and civil construction firms that support the ILC and are interested in participating in its construction. They keep up to date with R&D developments through semi-annual meetings such as this one.

The LCFOA provides a partnership between its industry members and the government, National Laboratories, universities, the ILC Global Design Effort (GDE) and the Americas Regional Team supporting the GDE throughout all phases of the ILC program. Read more...

Events (see all | submit)

• April 27: (12:30 p.m.) Experimental Seminar: Physics with Di-electron Final State at CDF
• April 27: (4:15 p.m.) ACKS Seminar - Zoltan Haiman

Access (see all)

• 4/25 - 4/28: PEP Ring Road Closure South of B750
• 3/27 - 4/28: Alpine Gate Temporarily Closed
• 3/31 - 4/30: Gate 17 Hours Extended During Alpine Gate Shutdown
• 3/28 - 4/30: Intermittent Narrowing of Loop Road Near Bldg. 35 and 81
• 1/1 - 5/1: Loop Road Near Kavli Building Temporarily Closed
• 1/1 - 5/1: North Gallery Road Closed at Sector 20
• 4/3 - 6/1: Short Spur Road Off North Access Road Closed

Announcements
(see all | submit)

 Lab Announcements

• Please remove all government vehicles from bldg 41 parking lot by Friday
• Register for SSI today: The Next Frontier: Exploring with the LHC
• ES&H Announces New Web-Based Training

Community Bulletin Board

• Stanford Food Drive This Friday
• Beginning Japanese class starts 5/3
• Stanford Drama Department's Spring Migration Dance Concert
• Women Leaders 2006: A Symposium for Women in University Settings

News (see all | submit)

• New NASA data shows that black holes are universe's 'greenest' systems Stanford University
• Making Collider Endorsement Count Nature
• eRHIC Gets to the Heart of the Matter Brookhaven
• No WIMPS—Only SuperWIMPS Physics Web

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What's Cookin' at the Linear Cafe (see weekly menu)

Thursday
Breakfast Boosters	Bacon, Egg, Cheese and Tomato Sandwich with Hash Browns Potatoes	$4.73
Hot	Five Onion Soup with Parmesan Cheese, Garlic Croutons or Turkey Tortilla Soup	$2.35/$2.95
Taste	Carved Ham or Roasted Turkey with Sweet Potatoes and Pineapple Sauce	$5.65
Good Food For You	Beef and Roma Tomatoes or Tofu Stir-fry with Vegetables	$5.65
Tossed	Grilled Chicken Caesar Salad	$5.45
Panini	Roast Beef with Creamy Horseradish and Grilled Onions	$5.45
Sandwich Favorite	Polish Sausage with Sauerkraut and Potato Salad	$4.99