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	Thursday, March 28, 2013

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Thursday, March 28

2:30 p.m.
Theoretical Physics Seminar - Curia II
Speaker: Aaron Pierce, University of Michigan
Title: Top Partners as a Window to Extended Scalar Sectors

3:30 p.m.
DIRECTOR'S COFFEE BREAK - 2nd Flr X-Over

THERE WILL BE NO ACCELERATOR PHYSICS AND TECHNOLOGY SEMINAR TODAY

4 p.m.
Special Joint Experimental-Theoretical Physics Seminar (NOTE DATE) - One West
Speaker: Lloyd Knox, University of California, Davis
Title: New Results from Planck

Friday, March 29

3:30 p.m.
DIRECTOR'S COFFEE BREAK - 2nd Flr X-Over

4 p.m.
Joint Experimental-Theoretical Physics Seminar - One West
Speaker: Steve Sekula, Southern Methodist University
Title: Latest ATLAS Higgs Results

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Wilson Hall Cafe

Thursday, March 28

- Breakfast: Greek omelet
- Chicken noodle soup
- Chicken fajita sandwich
- Chicken cacciatore
- Smart cuisine: Asian beef and vegetables
- Italian loaf sandwich
- Assorted pizza by the slice
- Tex-Mex grilled-chicken salad

Wilson Hall Cafe Menu

Chez Leon

Friday, March 29
Dinner
Closed

Wednesday, April 3
Lunch
Menu unavailable

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Call x3524 to make your reservation.

NOvA neutrino detector records first 3-D particle tracks

This cosmic-ray muon produces a large shower of energy as it passes through the NOvA detector. Image: NOvA collaboration

What will soon be the most powerful neutrino detector in the United States has recorded its first three-dimensional images of particles.

Using the first completed section of the NOvA neutrino detector, scientists have begun collecting data from cosmic rays—particles produced by a constant rain of atomic nuclei falling on the Earth's atmosphere from space.

"It's taken years of hard work and close collaboration among universities, national laboratories and private companies to get to this point," said Pier Oddone, director of the Department of Energy's Fermi National Accelerator Laboratory. Fermilab manages the project to construct the detector.

The active section of the detector, under construction in Ash River, Minn., is about 12 feet long, 15 feet wide and 20 feet tall. The full detector will measure more than 200 feet long, 50 feet wide and 50 feet tall.

Scientists' goal for the completed detector is to use it to discover properties of mysterious fundamental particles called neutrinos. Neutrinos are as abundant as cosmic rays in the atmosphere, but they have barely any mass and interact much more rarely with other matter. Many of the neutrinos around today are thought to have originated in the big bang.

"The more we know about neutrinos, the more we know about the early universe and about how our world works at its most basic level," said NOvA co-spokesperson Gary Feldman of Harvard University.

From symmetry

Astronomers give Dark Energy Camera rave reviews

Even before the Dark Energy Survey begins, the Dark Energy Camera is exceeding expectations in the astrophysics community. Photo: Anja von der Linden

Astronomer Daniel Kelson is part of a team working to answer an intriguing question about our universe: Why are fewer and fewer stars being created over time? He's been collecting data for years, but one piece of the puzzle eluded him.

That is, until December of last year, when he spent two nights in Chile observing the sky with the new Dark Energy Camera. Kelson came away from his observing session with the information he needed to complete his research, and with a healthy dose of respect for what he calls the "super camera," installed at the southern hemisphere station of the US National Optical Astronomy Observatory.

"It was beautiful to use," Kelson says. "It's impressive that the various teams could come together and make such a phenomenal camera."

He's not alone in his appreciation.

The 570-megapixel Dark Energy Camera—the world's most powerful digital imaging device, built at Fermilab and installed on the Blanco 4-meter telescope at the Cerro Tololo Inter-American Observatory in Chile—was constructed for the Dark Energy Survey, a five-year effort to map a portion of the southern sky in unprecedented detail. Since the camera was turned on in November, the DES has spent 50 nights completing the science verification phase of the experiment.

When DES members are not operating the camera, it's available for other astronomers like Kelson to use. Since last December, 19 other groups of scientists from institutions including Harvard, the University of Virginia and the University of California at Berkeley have signed up for nights with the Dark Energy Camera. Some teams searched for asteroids while some examined the properties of galaxies.

—Andre Salles

In the News

Viewpoint: Antiprotons reflect a magnetic symmetry

From Physics, March 25, 2013

Many physical laws are indifferent to distinctions such as left or right and forwards or backwards. On rare occasions, though, a discrepancy shows up, and we say that a symmetry is broken. One symmetry that has so far avoided any signs of breaking is the so-called CPT symmetry, which equates matter and antimatter at a fundamental level. A new test of CPT symmetry involves antiprotons. Specifically, Jack DiSciacca of Harvard University and his colleagues (the ATRAP Collaboration) present the most precise measurement to date of the antiproton magnetic moment. As reported in Physical Review Letters, the results match data on the proton, thus extending CPT's shatterproof status for the time being.

Frontier Science Result: CDF and DZero

Tevatron tests Higgs boson's fit into Standard Model

The combined Tevatron experiments test whether the Higgs boson follows the intricate blueprints of the Standard Model.

The Standard Model dictates the intricate relationships between the particles it describes, but does the Higgs boson follow that blueprint and fit those specifications? If so, the Higgs boson must have the predicted properties, including the correct production rate and the right preferences for decaying into other particles. The Tevatron experiments, CDF and DZero, have just released the results of their combined study of the Higgs boson, making best use of the decade's worth of data collected during Run II to improve the precision of this important test of the Standard Model.

The Higgs boson plays the important role of giving mass to other particles in the Standard Model and interacts with other particles in proportion to their masses. It does not decay into massless particles, like photons, except through processes involving intermediate massive particles. Coordinated efforts between teams of analyzers at each experiment ensured that analyses covered as many ways as possible that the Higgs boson could be produced and then decay. Each individual analysis was optimized to be as sensitive as possible to the Higgs signal.

All possible decays are considered when examining the total rate of Higgs boson production, though the Tevatron experiments are most sensitive to decays into pairs of bottom quarks when measuring individual decay channels. Both the total rate of Higgs boson production and the decay rate measured in each channel considered are found to be consistent with the Standard Model predictions. Further tests were performed to test for a preference for the Higgs boson to associate with either other bosons or quarks and leptons, but none of significance was observed. These results, which represent the culmination of many years of effort from the CDF and DZero collaborations, validate the Higgs boson's fit into the amazingly successful machinery of the Standard Model.

—Mike Cooke

These results would not be possible without the support the CDF and DZero collaborations receive from those outside our respective collaborations. We would like to recognize the important fundamental contributions the Accelerator Division, Particle Physics Division and Computing Division have made to our physics program. Our success is made possible through the continuing support of many national and international funding agencies, especially that of the Department of Energy and the National Science Foundation.

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