Thursday, Nov. 8, 2012

Have a safe day!

Thursday, Nov. 8

2:30 p.m.
Theoretical Physics Seminar - Curia II
Speaker: Christina Ignarra, Massachusetts Institute of Technology
Title: Recent MiniBooNE Results and the Status of Sterile Neutrinos

3:30 p.m.


Friday, Nov. 9

3:30 p.m.

4 p.m.
Joint Experimental-Theoretical Physics Seminar - One West
Speaker: Kenichi Hatakeyama, Baylor University
Title: Physics with the Upgraded CMS Detector

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a weekly calendar with links to additional information.

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Wilson Hall Cafe

Thursday, Nov. 9

- Breakfast: corned-beef hash and eggs
- White chicken chili
- Sloppy joe
- Beef stroganoff
- Smart cuisine: Mediterranean-style ziti with asparagus
- Buffalo chicken tender wrap
- Assorted pizza by the slice
- Grilled- or crispy-chicken Caesar salad

Wilson Hall Cafe Menu

Chez Leon

Friday, Nov. 9

Wednesday, Nov. 14
- Grilled flank steak
- Sautéed spinach with lemon
- Orzo with pine nuts and parmesan
- Chocolate pecan tart

Chez Leon Menu
Call x3524 to make your reservation.


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From symmetry

Voyage to SNOLAB

A growing number of scientists are looking for ways to join a dream team of experiments in a unique laboratory a mile and a half underground in Ontario. There, they seek to solve some of the biggest mysteries in physics today, including the case of missing dark matter. Image: Sandbox Studio, Chicago

In September, postdoc Hugh Lippincott prepared for a roadtrip that would take him and physicist Erik Ramberg northeast from their starting point near Chicago through Michigan and across the Canadian border. He stocked a cargo van they rented for the occasion with granola bars, apples and an iPod heavy on Pearl Jam. But this was no joyride. This was a practice run.

Loaded on springs and packed in a wooden crate in the back of the van was a stand-in for a piece of precious cargo: the quartz bell jar that makes up the heart and soul of the 60-kilogram COUPP dark matter experiment. Lippincott and Ramberg will soon transport the real thing—worth about $100,000 and a year of work—from Fermi National Accelerator Laboratory, just outside Chicago, to SNOLAB, an underground laboratory located 700 miles away in an active mine in Sudbury, Ontario.

Lippincott and Ramberg are not the first experimentalists to consider it worth the risk to move fragile equipment hundreds of miles to reach the laboratory, nor will they be the last. SNOLAB began as a single experiment looking to answer one of the biggest particle physics questions of its time. It has since expanded into an Olympic village of experiments tackling some of the most pressing questions of today.

Read more

Kathryn Jepsen

In Brief

Calling all veterans

On Monday, Nov. 12, the Fermilab Veterans Group will host their Veterans Day Celebration in Kuhn Barn. All veterans are welcome. The event takes place from 11:30 a.m. to 1:30 p.m.

For information or to join the group's e-mail list, contact Rafael Coll at x8518 or You can also view the Veterans Day Celebration poster for more information.

Photo of the Day

Still celebrating Halloween

Squirrels romp around a jack-o-lantern at Site 52. Photo: Lori Limberg, BSS
In the News

Doubt cast on Fermi's dark matter smoking gun

From New Scientist, Nov. 6, 2012

It was hailed as a smoking gun for dark matter, raising hopes that we might finally pinpoint the particle that is thought to make up 80 percent of the mass in the universe. But purported evidence of dark matter interactions in the centre of our galaxy may not be as solid as hoped.

Most physicists think dark matter is made of weakly interacting massive particles, or WIMPs, which only interact with normal matter via gravity. When two WIMPs meet, they should annihilate and spew out new particles, including high-energy gamma rays.

The Fermi Gamma-ray Space Telescope searches for dark matter by seeking these gamma rays. If it detects more gamma rays of a certain energy than known sources can explain, that would be thought by many to be a sign of WIMPs.

Read more
In the News

Viewpoint: 0 + 0 > 0

From Physics, Nov. 5, 2012

The idea that the whole can represent more than the sum of the parts is of fundamental importance in science, as illustrated in complexity theory: the emergent behavior of many complex systems cannot simply be derived from their individual components. In quantum mechanics, this phenomenon appears in a particularly subtle form: certain physical quantities, relevant to the description of quantum systems, are nonadditive. Loosely speaking, it is as if 0 + 0 > 0. Sometimes one can get something out of nothing! The origin of this effect lies in the fact that quantum mechanics allows for two (or more) systems to be measured jointly in a way that admits no analog in classical physics. Writing in Physical Review Letters, Carlos Palazuelos at the Institute of Mathematical Sciences in Spain presents a remarkable illustration of this phenomenon, showing that quantum nonlocality, arguably the most counterintuitive feature of quantum theory, is nonadditive: the combination of a number of local quantum states can be nonlocal.

Read more
Result of the Week

Digging for the golden Higgs at CDF

Output of the neural network used to separate 125-GeV/c2 Higgs boson signals from the multi-jet background. The multi-jet background is very large, so the lower plot shows the output with the multi-jet contributions removed. The data tends to follow the background prediction, which implies no Higgs boson has been observed.

Searching for gold is a hard game—you spend so much time digging through the dirt. But if you persist, you may find a huge bounty of treasures ... much like searching for the Higgs boson.

Scientists have been seeking the Higgs boson for almost 50 years and have recently found evidence for it from the Tevatron. They have also observed a 125-GeV/c2 Higgs-like particle at the LHC.

The unique all-hadronic Higgs channel at CDF searches for Higgs decays into pairs of bottom quarks accompanied by two additional quarks. The search could uncover a huge treasure trove of Higgs particles, but you have to dig through a multi-jet background that's a million times larger than the Higgs. Another difficulty is that the quarks are not directly observed in the CDF detector since they immediately fragment into jets.

CDF physicists took on the challenge of searching for these quark combinations and improved measurements of variables sensitive to Higgs boson production, such as the width of jets. They used a neural network (a computer "brain") to separate the multi-jet background from the golden Higgs events.

The physicists improved the energy resolution of bottom quark jets by 18 percent, which increased the potential Higgs yield by 10 percent. They then used information from CDF's trackers and calorimeters to measure a subtle difference in jet widths between those of quark jets and those of gluons, which look almost identical to quark jets. (True gluon jets tend to fragment over a slightly larger area.) This measurement helped to separate the golden Higgs events from the background. The improved measurements of the bottom quark energy, jet width and other information were fed to a special two-layer neural network to simultaneously identify Higgs bosons produced by three different processes.

Despite the enormous challenges, these innovations improved the search's sensitivity by 40 percent compared to our previous search, which is the equivalent of gaining an additional 2.5 years of Tevatron data. The limits placed on the Higgs search are given in the lower plot, which shows that for a Higgs mass of 125 GeV/c2, the expected (observed) limit is 11.0 (9.0) times the Standard Model prediction. The CDF all-hadronic Higgs search is as sensitive as CDF's ttH and Hγγ searches and has not been attempted at the LHC. These innovations also have applications to future multi-jet searches.

Learn more

edited by Andy Beretvas

Observed and expected 95 percent credibility level upper limits on (WH, ZH, vector boson fusion) Higgs cross section times the branching ratio for Higgs → bb divided by the Standard Model prediction, as a function of the Higgs mass.
These CDF physicists contributed to this data analysis. Top row from left: Yen-Chu Chen (Academia Sinca, Taiwan) and Francesco Devoto (University of Helsinki, Finland). Bottom row from left: Ankush Mitra and Song-Ming Wang, both from Academia Sinca, Taiwan.

Deadline for UChicago Tuition Remission Program - Nov. 26

Writing for Results: E-mail and More class - Nov. 29

Calling all veterans 

Martial Arts class

Windows 8 at Fermilab

Additional professional development courses

Fermilab discount: "QED" - a day in the life of Richard Feynman

Country House employee discount

Atrium work updates