Friday, March 8, 2013

Have a safe day!

Friday, March 8

3:30 p.m.

4 p.m.
Joint Experimental-Theoretical Physics Seminar - One West
Speaker: Manuel Franco Sevilla, University of California, Santa Barbara
Title: Evidence for an Excess of B → D* Tau Nu Decays and Implications for Two Higgs Doublet Models

Sunday, March 10

2:30 p.m.
Gallery Chamber Series - 2nd Flr X-Over
Arianna String Quartet
Tickets: $17

Monday, March 11


3:30 p.m.


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Wilson Hall Cafe

Friday, March 8

- Breakfast: French bistro breakfast
- Tomato basil bisque
- Becks battered fish sandwich
- Vegetarian lasagna
- Smart cuisine: herb and lemon fish
- Cuban panini
- Assorted pizza by the slice
- Mumbo jumbo baked potatoes

Wilson Hall Cafe Menu
Chez Leon

Friday, March 8
- Pasta carbonara
- Stuffed filet of sole with crab
- Sautéed spinach
- Pecan rum cake

Wednesday, March 13
- Enchilada de mole with chicken
- Spanish rice
- Refried beans
- Lemon mousse

Chez Leon Menu
Call x3524 to make your reservation.


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Fermilab deliberates potential of former Tevatron's cooling pond system

The Tevatron and Main Injector cooling ponds are visible as the iconic double loop on Fermilab grounds. Much of the Tevatron's cooling system shut down when the Tevatron turned off in 2011. Laboratory engineers are investigating ways to revive the Tevatron cooling ponds. Photo: Reidar Hahn

A mark of some of the world's most powerful particle accelerators, past and present, is the underground loop through which scientists accelerate subatomic particles to investigate the many mysteries of the universe. Crucial to keeping particle accelerators alive are the cooling systems that prevent damage from overheating. In Fermilab's case some of those cooling systems make up the iconic double loop that adorns the grounds.

The two loops, which trace the tunnels of the Main Injector and the former Tevatron, are a system of man-made water trenches. Before the Tevatron shut down in 2011, engineers would pump water from the trenches, called cooling ponds, into service buildings. The service buildings would then direct the water through heat exchangers, transferring heat from the Tevatron low-conductivity water cooling system. But when the Tevatron shut down, so did the cooling system.

"You can't beat the efficiency of water cooling," said Kent Collins, the deputy head of the Facility Engineering Services Section. "The cooling ponds did a phenomenal job for as long as we ran, but now they're just like any other pond."

During Tevatron operations, as many as 30 service buildings, divided into six operational sectors, directed the cooling water. Near-term plans call for one sector to remain operational for post-Tevatron operations. Service buildings will help cool accelerator components that will send beam to external beamline experiments such as Seaquest and MTest experiments.

The Main Injector ponds will also remain active, providing cooling for beamlines to the laboratory's neutrino programs, such as NOvA.

As for the other cooling pond sectors—they now host beavers and are slowly eroding. Once 7 feet deep when constructed in the 1970s, most are now 1 to 2 feet deep. Yet their story may not be over, said the Accelerator Division's Maurice Ball, whose group is looking at ways the lab could revive some of the ponds.

"The way that the ponds operated for the Tevatron was through a domino drainage effect from one sector to the next, but that may not work for future projects that may use these ponds," Ball said. "The Accelerator Division is working with Facilities Engineering to figure out how we could reconfigure existing pond infrastructure at minimal cost to maintain a more efficient pond circulation for possible future projects." The projects include Mu2e, Muon g-2 and work under consideration at CDF and DZero.

Recommissioning the shallow ponds for short-term needs may be reasonable, but the longer the mechanical systems are inactive, the greater the restoration cost will be, Collins warned. Without increasing the ponds' depth, the heat load they will be able to manage will also be limited.

"For any project with an extended run, the ponds will require renovation," Collins said. "Our near term plan will leave the piping and other infrastructure in place and use the dried ponds as vegetated drainage swales. Future projects will determine when reviving ponds is cost-effective compared to alternative cooling sources."

Jessica Orwig

Photo of the Day

Keeping the Main Injector cool

The water sprayers by MI60 at the Main Injector keep the water at the right levels. Elliott McCrory, AD, photographed this scene just after sunset using a long exposure.
From symmetry

Higgs-like particle still looking like the Higgs

Scientists have started to exclude some of the more exotic scenarios for the Higgs-like boson. Photo: ATLAS

The Higgs-like boson discovered in 2012 is looking more Higgs-like, scientists on experiments at the Large Hadron Collider said in presentations at the Rencontres de Moriond physics conference Wednesday.

On July 4, 2012, scientists first announced the discovery of a new particle that could be the Higgs boson. The Higgs boson is, or was, the last undiscovered particle in the Standard Model, a menu of the particles and forces that serve as the building blocks of the universe.

Final judgment of whether the new boson is the predicted Higgs particle will likely have to wait until sometime after the LHC resumes running at higher energies in 2015.

Read more

Kathryn Jepsen

In the News

Monster bubbles evidence of dark matter?

From ABC Science, March 6, 2013

Monster outflows of charged particles stretching above and below the center of the Milky Way could contain tantalizing evidence of mysterious dark matter, say scientists.

Although dark matter constitutes 84 percent of all matter in the universe, it has never been seen.

Its existence has only been inferred from its gravitational effects on visible matter, radiation, and the large scale structure of the universe.

Writing on, Dan Hooper from Fermi National Accelerator Laboratory and Tracy Slatyer from Princeton University say dark matter could be causing some of the features seen in Fermi bubbles.

Read more
Frontier Science Result: CMS

Top quark cross section

Although cross section has little to do with a literal slice of the top quark, it can tell us about the quark's fundamental properties.

Last week's Physics in a Nutshell described the strange way that particle physicists use the term "cross section" to mean a reaction rate. For instance, the proton-proton to top-antitop cross section is related to the probability that two protons will interact and produce a top quark and an antitop quark. This idea of cross section has historical roots in the fact that the collision probability of a stream of spherical balls is proportional to the cross sectional area of those balls. Today, the term is used because it specifies the collision probability in a way that is independent of the number of particles in the stream, so that results from one accelerator can be compared with results from another.

But why measure collision probabilities at all? Back when particles were thought to be hard spheres, it was an indirect way of measuring their size. In our current understanding, each particle is a quantum cloud of probable positions, and even if two particle clouds pass through each other, they may or may not interact. The probability of interaction is only partly determined by position—it is also affected by a fundamental property known as coupling, the strength of connection between the colliding particles and the result of the collision. When protons collide, the probability of making a top-antitop pair depends on the coupling of gluons inside the proton with the top quarks. By measuring this cross section, scientists learn how strongly gluons and top quarks are related, one link in the web that connects all fundamental particles.

In a recent paper, CMS physicists presented a new measurement of proton-proton to top-antitop cross section, using 60 times more data than the previous measurement. The extra precision that the large data set provides not only tests our understanding of the gluon-top coupling, it also checks assumptions about the density of gluons in the proton and quantifies a background for other searches. As the heaviest particle known, the top quark couples more tightly than any other to the Higgs boson and anything related to the origin of mass—the more we know about it, the better.

—Jim Pivarski

The physicists pictured above carefully measured the production cross section of top-antitop pairs in proton collisions.
The physicists pictured above made significant contributions to CMS missing energy reconstruction, ranging from data quality monitoring tools to novel approaches of reducing dependence on overlapping events (pileup).
Special Announcement

Change your clocks, change your batteries

The members of the Fermilab Fire Department want to remind you that daylight-saving time begins this Sunday at 2 a.m. When you set your clocks forward an hour, remember to check and/or change the batteries in flashlights as well as your smoke and carbon monoxide detectors. You should also remove dust from detectors monthly for proper operation. Statistics show that properly working smoke detectors save lives. Contact the Fire Department at x3428 with any questions.

Special Announcement

Hawk Talk: Saturday, March 9

Fermilab Natural Areas presents "Hawk Talk: Raptors at Fermilab" this Saturday from 10 a.m. to noon in Curia II (second floor of Wilson Hall, next to the Art Gallery). Larry Miller will talk about the natural history of raptors and explain basic identification features. The event is free and open to the public.


Today's New Announcements

Job Descriptions and Employment class - March 22

Fermilab Natural Areas: Hawk Talk: Raptors at Fermilab - March 9

Fermilab Chamber Series: Arianna String Quartet - March 10

Barn dance - March 10

Extended network outage at Wilson Hall - March 10

Book fair - March 11

FMLA (Family Medical Leave Act) seminar - March 12

Walk 2 Run - March 14

Abri Credit Union member appreciation - March 14

Healthcare spending account deadline - March 15

Fermilab Lecture Series: The Believers (documentary) - March 15

Fermilab Arts & Lecture Series: ScrapArtsMusic - March 23

DOEGrids certificates to be decommissioned - March 23

Nominations open for 2013 Tollestrup Award - through April 1

2013 FRA scholarship applications accepted until April 1

Writing for Results: E-mail and More - May 3

Interpersonal Communication Skills course offered in May

Fermilab Management Practices courses now available for registration

Scottish country dancing meets Tuesday evenings in Kuhn Barn

Indoor soccer

Employee discounts

Find new classified ads on Fermilab Today.