Arrows in the center of this image point toward the supermassive black hole at the galactic center of the Milky Way galaxy. GLAST data may soon provide evidence of WIMP-burning stars nearby. (Image courtesy of the European Southern Observatory.)

Hey, WIMPs—Beware of Dwarfs

by Alison Drain

Stars may be bullies in their old age. White dwarfs—dense, collapsed stars in their final stage of life—could be skilled at swallowing and annihilating weakly interacting massive particles (WIMPs). These particles may constitute a large portion of the dark matter in the universe, and could form extremely dense concentrations near supermassive black holes. Physicists Igor Moskalenko and Lawrence Wai plan to glean GLAST data to learn whether these concentrations of dark matter exist. If they do, WIMP-swallowing stars could reveal the secrets of black holes. Their paper will be published in the April 10 issue of Astrophysical Journal Letters.

"This research could reveal a completely new kind of star, and could provide insight into how supermassive black holes evolve," Wai said. "We're very excited about this possibility." Read more...

A New (or Old) Way to Make Gravity Consistent with Quantum Mechanics?

by Lance Dixon

A diagram providing a "window" into N=8 supergravity at the third quantum-mechanical order.

In 1916, Albert Einstein proposed his general theory of relativity, which describes the gravitational force in terms of curved space-time. This theory has successfully predicted gravitational lensing of light, relativistic time delays, black holes and gravitational radiation (the latter has only been detected indirectly so far). Yet all of these tests have been at the classical level, ignoring the effects of quantum mechanics. For several decades, physicists have tried to extend Einstein's general theory of relativity into the quantum realm. Experimental tests are hard to come by here, so theoretical consistency has been the coin of the realm. Recently, a few different theoretical investigations have suggested that an old theory of quantum gravity might actually be consistent, contrary to the prevailing wisdom over the intervening decades.

Early attempts to make consistent quantum theories of gravity assumed that all particles were point-like, with no extended structure. Such an approach has worked extremely well for the other three known forces, the strong, weak and electromagnetic interactions. The quantum theory of these forces, the Standard Model, has survived intense experimental scrutiny for three decades. Read more...

Have You Nominated That Special Person Yet?

by Larissa Williams

The 2007 Employee Recognition Awards ("globies") are still open for nominations!

Until Monday, April 2, you can recommend people as candidates for this special award. Globies are about people promoting a positive, respectful, and harmonious work environment. They're about good citizenship and making everyone enjoy being at SLAC.

The online form lists several different examples of how people make our lives better at SLAC. They include working cooperatively, volunteering, and pitching in to help. When nominating somebody, please keep in mind that it's not about how well a person does their job—it's what they do beyond their job that makes them special.

You're the only one who knows the little things these people do that help make your day brighter and easier. Your nomination that will let everybody else know it too. Please be as detailed as possible when filling out the form, and provide several examples. Help the people who help you by nominating them for a Globie Award.

Save the Date:
SLAC at Community Day

This year's Community Day will draw a crowd of thousands to Stanford on Sunday, April 15 from 10 a.m. to 4 p.m., for a day of activities, performances and lectures sponsored by academic departments and student groups from all over the Stanford campus. SLAC will host a display booth at the open-house event—there will be ice cream and giveaways, film screenings and fun, so save the date and join us. Bring your family and friends!

To volunteer or for more information please contact Melinda Lee at x8547.

Events (see all | submit)

March 29: (12:30 p.m.) Experimental Seminar: Cosmic Rays and Supernovae: Developing Techniques
April 4: (1:30 p.m.) AIS Seminar: Laser Wakefield Acceleration

Access (see all)

Announcements
(see all | submit)

Lab Announcements

Community Bulletin Board

News (see all | submit)

PPARC Announces £30m for Physics Grid Lightsources.org
Quantum Lottery is Your Best Bet Physics Web
Scientists Unlock Physical, Chemical Secrets of Plutonium PhysOrg.com

<% Response.AddHeader "Last-modified", getArticleDate() 'Response.AddHeader "Last-modified","Mon, 01 Sep 1997 01:03:33 GMT" 'Monday, December 06, 2010 %>

View online at http://today.slac.stanford.edu/.

Arrows in the center of this image point toward the supermassive black hole at the galactic center of the Milky Way galaxy. GLAST data may soon provide evidence of WIMP-burning stars nearby. (Image courtesy of the European Southern Observatory.) Hey, WIMPs—Beware of Dwarfs by Alison Drain Stars may be bullies in their old age. White dwarfs—dense, collapsed stars in their final stage of life—could be skilled at swallowing and annihilating weakly interacting massive particles (WIMPs). These particles may constitute a large portion of the dark matter in the universe, and could form extremely dense concentrations near supermassive black holes. Physicists Igor Moskalenko and Lawrence Wai plan to glean GLAST data to learn whether these concentrations of dark matter exist. If they do, WIMP-swallowing stars could reveal the secrets of black holes. Their paper will be published in the April 10 issue of Astrophysical Journal Letters. "This research could reveal a completely new kind of star, and could provide insight into how supermassive black holes evolve," Wai said. "We're very excited about this possibility." Read more...

A New (or Old) Way to Make Gravity Consistent with Quantum Mechanics? by Lance Dixon A diagram providing a "window" into N=8 supergravity at the third quantum-mechanical order. In 1916, Albert Einstein proposed his general theory of relativity, which describes the gravitational force in terms of curved space-time. This theory has successfully predicted gravitational lensing of light, relativistic time delays, black holes and gravitational radiation (the latter has only been detected indirectly so far). Yet all of these tests have been at the classical level, ignoring the effects of quantum mechanics. For several decades, physicists have tried to extend Einstein's general theory of relativity into the quantum realm. Experimental tests are hard to come by here, so theoretical consistency has been the coin of the realm. Recently, a few different theoretical investigations have suggested that an old theory of quantum gravity might actually be consistent, contrary to the prevailing wisdom over the intervening decades. Early attempts to make consistent quantum theories of gravity assumed that all particles were point-like, with no extended structure. Such an approach has worked extremely well for the other three known forces, the strong, weak and electromagnetic interactions. The quantum theory of these forces, the Standard Model, has survived intense experimental scrutiny for three decades. Read more...	Have You Nominated That Special Person Yet? by Larissa Williams The 2007 Employee Recognition Awards ("globies") are still open for nominations! Until Monday, April 2, you can recommend people as candidates for this special award. Globies are about people promoting a positive, respectful, and harmonious work environment. They're about good citizenship and making everyone enjoy being at SLAC. The online form lists several different examples of how people make our lives better at SLAC. They include working cooperatively, volunteering, and pitching in to help. When nominating somebody, please keep in mind that it's not about how well a person does their job—it's what they do beyond their job that makes them special. You're the only one who knows the little things these people do that help make your day brighter and easier. Your nomination that will let everybody else know it too. Please be as detailed as possible when filling out the form, and provide several examples. Help the people who help you by nominating them for a Globie Award. Save the Date: SLAC at Community Day This year's Community Day will draw a crowd of thousands to Stanford on Sunday, April 15 from 10 a.m. to 4 p.m., for a day of activities, performances and lectures sponsored by academic departments and student groups from all over the Stanford campus. SLAC will host a display booth at the open-house event—there will be ice cream and giveaways, film screenings and fun, so save the date and join us. Bring your family and friends! To volunteer or for more information please contact Melinda Lee at x8547.	Events (see all \| submit) March 29: (12:30 p.m.) Experimental Seminar: Cosmic Rays and Supernovae: Developing Techniques April 4: (1:30 p.m.) AIS Seminar: Laser Wakefield Acceleration Access (see all) Alpine Gate & PEP Ring Road closed Gates 17 & 30 open 24-7 Research Yard bisected Announcements (see all \| submit) Lab Announcements New Publication: ESH Manual, Chapter 49, Service Subcontractor Safety 2007 Employee Recognition Awards open for nominations through Monday Community Bulletin Board Panofsky Colloquium "Nuclear Weapons: Security or Insecurity?" now online Getting Results: The Next Generation of Women Scientists News (see all \| submit) PPARC Announces £30m for Physics Grid Lightsources.org Quantum Lottery is Your Best Bet Physics Web Scientists Unlock Physical, Chemical Secrets of Plutonium PhysOrg.com
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