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In this issue:
Researchers Trace the Origin of Super‑massive Black Holes
ATLAS Workshop Under Way at SLAC
Seen around SLAC: KIPAC Picnic

SLAC Today

Thursday - August 26, 2010

Researchers Trace the Origin of Super‑massive Black Holes

These simulated images show the evolution of a gas disk created by the collision of two identical protogalaxies, from the disk's formation (upper left) until the onset of central collapse (lower right). Brighter colors indicate regions of higher density. (Image courtesy L. Mayer et al.)

In the very early universe, soon after the first stars formed, black holes more massive than a billion Suns already speckled the sky. For years, these super-massive black holes were a cosmic anachronism. Although cosmologists put forth two theories for how they might have formed, neither offered a satisfying explanation for how these behemoths came into existence less than a billion years after the Big Bang. Now, in a paper published today in Nature, a team of researchers describe a third theory.

"Putting together a viable model for the origin of these super-massive black holes is a difficult theoretical task," said Stelios Kazantzidis, a former researcher at the SLAC/Stanford Kavli Institute for Particle Astrophysics and Cosmology who now works at The Ohio State University's Center for Cosmology and AstroParticle Physics. "Yet we know from observations that super-massive black holes existed very early on in the history of the universe."  Read more...

ATLAS Workshop Delves into the Data

U.S.-based ATLAS physicists met at SLAC this week. Above, the full ATLAS collaboration. (Image courtesy ATLAS collaboration.)

The fourth annual ATLAS Hadronic Final State Forum took place at SLAC this week, where U.S.-based physicists involved in the ATLAS collaboration at CERN looked at various aspects of the current experimental data. ATLAS—A Toroidal LHC ApparatuS—is one of six particle detector experiments at CERN's Large Hadron Collider. By analyzing the jets of particles that spew from proton-proton collisions in the LHC, the collaboration searches for evidence of some of the basic forces that shape our universe, including the origin of mass and the existence of dark matter.

SLAC has hosted the annual workshop, attended primarily by collaborators based on the west coast, since 2007. This year the participants discussed both the first experimental results from ATLAS and the Compact Muon Solenoid at the LHC as well as theoretical expectations for new physics that might arise from the findings.

"This year's conference was unique in that we had access to data, so attendees could analyze problems and consult the experts who were here," said SLAC physicist Ariel Schwartzman, who coordinated the workshop with Peter Loch, a physicist at the University of Arizona. The week consisted mainly of interactive working groups and discussions, which Loch and Schwartzman hope will help researchers identify common interests and form new collaborations to address the experiment's many unresolved challenges.

Seen near SLAC: KIPAC Picnic

(Photo by Kelen Tuttle.)

Last Friday, nearly 100 researchers, staff members and friends of the Kavli Institute for Particle Astrophysics and Cosmology gathered in Palo Alto's Mitchell Park to celebrate another year of great science.

(Photo by Kelen Tuttle.)

The fourth annual picnic, which lasted from 4:30 p.m. until dusk, included a students vs. post-docs softball game (the students won), a water balloon toss (during which meeting organizer Ziba Mahdavi got a little more drenched than most), and plenty of time to sit back and enjoy the sunshine.

"It's a great opportunity for folks to talk outside the work environment and for families to get together," said Mahdavi, who organized the event with Martha Siegel and Phil Marshall. "It's always fun."


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