Thursday, July 10, 2014

Thursday, July 10

Undergraduate Lecture Series - One West
Speaker: Hugh Lippincott, Fermilab
Title: Searching for Dark Matter


3:30 p.m.

Friday, July 11

3:30 p.m.

4 p.m.
Joint Experimental-Theoretical Physics Seminar - One West
Speaker: Tulika Bose, Boston University
Title: Summer 2014 Results from CMS

8 p.m.
Fermilab Lecture Series - Auditorium
Speaker: Philip Troyk, Illinois Institute of Technology
Title: Technology for Advanced Neural Prostheses
Tickets: $7

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Wilson Hall Cafe

Thursday, July 10

- Breakfast: Canadian bacon, egg and cheese Texas toast
- Breakfast: sausage gravy omelet
- Italian combo sandwich
- Smart cuisine: finger-lickin' baked chicken
- Mom's meatloaf
- Rosemary chicken with sun-dried tomatoes
- Greek chicken salad
- Meatball and orzo soup
- Chef's choice soup
- Assorted pizza by the slice

Wilson Hall Cafe menu

Chez Leon

Friday, July 11
- Roasted vegetables with pasta
- Striped bass
- Lemongrass rice
- Wilted spinach
- Lime tart

Wednesday, July 16
- Chipotle chicken taco salad
- Banana dulce de leche pie

Chez Leon menu
Call x3524 to make your reservation.


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The sky is not the limit: DES gets time on Gemini telescope

The Dark Energy Survey was recently awarded 276 hours on the Gemini South telescope. Photo: Gemini Observatory/Association of Universities for Research in Astronomy

In an ambitious five-year mission, the Dark Energy Survey team has devoted itself to mapping the southern sky in unprecedented detail, ultimately hoping to decipher what may stand as the most bewildering phenomenon of our expanding universe.

In March, DES applied to the Large and Long Program at the Gemini Observatory, a program meant to foster scientific exploration through global collaboration. Although the Gemini Observatory has existed since 2000, the Large and Long Program launched just last year as another means to probe the shrapnel of the big bang. It offers time on two of the world's finest telescopes, one located atop an 8,900-foot mountain in the Chilean Andes (Gemini South) and the other on Mauna Kea, Hawaii (Gemini North).

Just last month, co-leader of the Strong Lensing Science Working Group at DES, Liz Buckley-Geer, received the email she'd been waiting for: Spread over the next three years, DES had been awarded a lofty total of 276 hours on Gemini South.

"Because we were asking for such a big block of time I really didn't think we had much of a chance," Buckley-Geer said. "I was pretty gobsmacked when I got the email two weeks ago."

With a hefty 8.1-meter mirror, the Gemini telescope is twice as large as the telescope on which DECam is currently mounted. But DES scientists don't plan to take new images with Gemini South. DECam images are plenty clear and show high-quality snapshots of galaxies and galaxy clusters. Instead of imaging, DES scientists will use an instrument called a spectrograph to further inspect the images and, in some cases, confirm a rare phenomenon called strong lensing.

One of five methods DES uses to explore dark energy, strong lensing is the bending of light from a distant galaxy, or source, due to the gravitational influence of a massive foreground object, or lens. Lensing changes the observed shape of the distant galaxy and intensifies brightness. To find these strong lensing systems in the DECam images, DES scientists look for objects that look distorted, often appearing as long bright arcs, multiple blue knots or, in the rarest cases, an Einstein ring. DES will focus on certain classes of strong lenses that can be used to study dark energy.

"The strong lenses provide a kind of peephole to the more distant, fainter universe that wouldn't be available if the lenses weren't there," said DES Operations Scientist Tom Diehl.

But what appear to be strong lenses are not always so. To separate the lenses from the impostors, scientists measure the redshifts of both the lens and the source. A true strong lens is one in which the source redshift is larger than the lens redshift.

A redshift occurs when light wavelengths increase, or shift toward the red side of the electromagnetic spectrum. The measured redshift of a galaxy is related to the expansion of the universe as a function of time, and it allows DES scientists to calculate the distance to the object.

To determine the redshift of a galaxy, the scientists will compare the spectrum of the obtained light with known features in the spectrum of various chemical compounds found on Earth. If the same features are seen in an observed spectrum from a distant source but occur at shifted wavelengths, then the redshift can be calculated.

"The observations with Gemini will give us the redshifts of all these objects, and armed with that information we can move on to the next step," Buckley-Geer said. "It's not all the information we need, but it's one piece of the jigsaw puzzle closer to understanding these system in relation to dark energy."

Hanae Armitage

Pictured are some of the 29 Dark Energy Survey scientists from Australia, Brazil, Japan, Switzerland, Taiwan, the United Kingdom and the United States who were involved in the Gemini proposal. Image courtesy of Elizabeth Buckley-Geer, SCD
In the News

Hultgren announces Oswego student as winner of House student app contest

From, July 9, 2014

Washington, DC – U.S. Representative Randy Hultgren (IL-14), member of the House Science, Space and Technology Committee and co-chair of the STEM Education Caucus, today announced the winner of the first-ever Congressional Science, Technology, Engineering and Math (STEM) Academic Competition, the "House Student App Challenge," also known as the "House App Contest." Jake Cirino of Oswego High School was selected by area judges from the computer science and technology fields for his app, "Pollution Simulator."

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Frontier Science Result: CDF

Two B mesons violate CP

N is the number of events determined by a fit for each decay mode. The first uncertainty is statistical, and the second is systematic.

In 1957 Lev Landau postulated that the laws of physics are symmetric under charge parity. This means that a mirror reflection of a particle with a particular charge and handedness would yield a particle of opposite charge and handedness. For example, a left-handed electron is transformed under charge parity to a right-handed antielectron.

In 1964 Cronin, Fitch and collaborators observed that charge parity, or CP, invariance was broken by a small amount in the decay of a neutral kaon. This means the decay, in producing particles of opposite charge, does not always produce particles of opposite handedness.

It was only in 2001 that CP violation was observed in B meson experiments done at the B factories such as SLAC's BaBar experiment and KEK's Belle experiment. In today's result, CDF physicists looked for CP violation in the decays of neutral hadrons containing a b quark, in particular, a neutral B meson (made of a d quark and a b antiquark), a strange B meson (made of an s quark and a b antiquark) and a Λ baryon (made of an up, down and b quark).

For example, we look at the decay rate for a neutral B meson to decay into a positive kaon and a negative pion. We also look for the corresponding antimatter decay. The asymmetry is given by the difference between the two rates divided by their sum.

The experiment is difficult because the occurrence of this particular decay chain is rare: The neutral B meson decays into a positive kaon and negative pion 2 times out of every 100,000 decays. Another difficulty is particle identification — the separation of pions from kaons. Scientists identify the particles by measuring the energy deposited in the detector's drift chambers. The experiment must also determine how efficiently the detector measured the particles' decays as compared with their corresponding antiparticle states.

The results are summarized in the above table. No asymmetry is seen for the two different decay modes of the Λb, so there is no evidence of CP violation in the decay of this particle. The asymmetry of the B0 → K+π- decay is measured with a significance of greater than five sigma. The measurement is in agreement with those at the B factories and the LHCb experiment at the LHC, thus corroborating evidence of CP violation in this decay. We also confirm the recent result by LHCb of the first measurement of the asymmetry for the strange B meson system. This large asymmetry is consistent with the Standard Model.

Learn more

edited by Andy Beretvas

These CDF physicists contributed to this data analysis. From left: Michael Morello (INFN, Pisa, Scuola Normale Superiore), Giovanni Punzi (INFN, Pisa) and Fabrizio Ruffini (INFN, Siena).
Photo of the Day

Coyote pup

While local resident Paige Nussbaumer was visiting the Fermilab site with her family, she took this photo of a coyote pup. Photo: Paige Nussbaumer
In the News

ESS gets the green light

From European Spallation Source, July 4, 2014

The Member Countries of the European Spallation Source have reached an agreement and secured funding for one of Europe's largest new facilities. That is according to the Swedish Minister of Education and Research Jan Björklund who made the statement at a press conference in Visby, Sweden.

"It has been a long process since the government in 2007 decided that we would try to get this prestigious project to Sweden," says Björklund. The confirmation to move ahead comes as Germany stated its intention to join the project and pay 11 percent of the €1,84 billion construction costs. That decision follows months of discussions between the members about financing the construction and operations costs.

Read more


Today's New Announcements

Outdoor soccer

Lecture Series - Technology for Advanced Neural Prostheses - July 11

Deadline for on-site housing requests for fall 2014 and spring 2015 - July 14

Fermilab prairie plant survey - July 23, Aug. 9

Scottish country dancing Tuesday evenings in Ramsey Auditorium

International folk dancing Thursday evenings in Ramsey Auditorium

Fermi Days at Six Flags Great America

Employee Appreciation Day at Hollywood Palms Cinema