Friday, Aug. 17, 2012

Have a safe day!

Friday, Aug. 17
3:30 p.m.

4 p.m.
Joint Experimental-Theoretical Physics Seminar (NOTE LOCATION) - Auditorium
Speaker: Tulika Bose, Boston University
Title: Review of LHC Summer 2012 Results (in conjunction with HCP Summer School)

Saturday, Aug. 18
8 p.m.
Fermilab Arts Series - Auditorium
Howard Levy & Chris Siebold

Monday, Aug. 20

3:30 p.m.


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Wilson Hall Cafe

Friday, Aug. 17

- Breakfast: French bistro breakfast
- New England clam chowder
- Becks-battered fish sandwich
- Tortellini primavera
- Smart cuisine: herb and lemon fish
- Cuban panini
- Garden vegetable pizza by the slice
- Chili cheese nacho platter

Wilson Hall Cafe Menu
Chez Leon

Friday, Aug. 17

Wednesday, Aug. 22
- Chile rellenos
- Spanish rice
- Confetti salad
- Pineapple flan

Chez Leon Menu
Call x3524 to make your reservation.


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From symmetry breaking

Experiments reveal new techniques in studying quark-gluon plasma

Experiments at RHIC and the LHC have complementary strengths in studying the quark-gluon plasma, a state of matter in which quarks come unbound. Image: Brookhaven National Laboratory

Carefully examining H2O molecules at room temperature will tell you a lot about the structure of water. But you need to vary the conditions to gain much insight into how it becomes vapor or ice.

In the past year, scientists at two large particle accelerators have been making these types of adjustments, studying their subject at a wide range of energies. Only they're not changing the temperature of water; they're tweaking a state of matter 100,000 times hotter than the interior of the Sun – the quark-gluon plasma.

"We are rapidly entering an era of detailed investigation," said CERN theoretical physicist Urs Wiedemann. "At the moment, nature has given us just the right tools to study the properties of the QGP."

The quark-gluon plasma is a state of matter in which quarks, which usually exist only in pairs or threes, float freely in a hot cosmic soup. Theorists think the universe existed in this state microseconds after the big bang, just before cooling into the normal state of matter we see today.

Understanding the properties of the QGP does not fully explain how the universe formed the way it did, Wiedemann said.

"It's like asking how a child's nutrition at age 10 affected his height at age 18," he said. "Clearly his nutrition affected it, but it's just one of many factors."

Still, he said, it's worth studying. Of the multiple phase transitions that theorists think the universe underwent after the big bang, only the one between the QGP and normal matter is currently accessible to man-made experiments.

Read more

Kathryn Jepsen

In Brief

White House congratulates US CMS, US ATLAS on recent particle discovery

On Aug. 8, Director of the U.S. Office of Science and Technology Policy John Holdren sent a letter to Fermilab's Joel Butler, operations program manager for US CMS, congratulating the CMS collaboration on the July discovery of a new Higgs-like boson.

The ATLAS collaboration also received a letter of congratulations from Holdren.

Photo of the Day

Hadron Collider Physics School summer students

Students conclude their two-week session at this summer's Fermilab-CERN Hadron Collider Physics School today. Photo: Reidar Hahn
In the News

Slice of life: A scientific mind

From the Kane County Chronicle, Aug. 16, 2012

BATAVIA – Fermilab engineer physicist Fernanda Garcia gently brought down the copper pipe that is part of the powerful linear accelerator at Fermilab.

On Tuesday, Garcia and others worked swiftly, yet carefully, to replace a tube in the accelerator, which provides the beam for high-energy physics research and neutron radiation therapy.

"Without a new tube, the beam would just stop working," Garcia said. "It's just like your Christmas tree lights. If one stops working, they all stop working."

It's her job to make sure the accelerator operates correctly. The scientists at Fermilab use high-energy physics to understand the fundamental nature of matter and energy. At a price of $65,000, it's a good thing she doesn't have to replace it all the time. It's been about three years since it's been replaced.

"If we are down, everybody is down," Garcia said. "There is a lot of pressure to make sure we do the work safely."

In her job, Garcia spends as much time doing "hands on" work as she does in her office. She enjoys both.

"After this project, I will go back to my office and do programming and analysis," Garcia said. "You really have a chance to do so many different things."

Read more

CMS Result

Taking them all on at once

Ready to trounce a continuum of supersymmetric models in one blow.

Supersymmetry, the notion that matter and forces are two sides of the same coin, is an elegant idea that could explain many of the mysteries of particle physics. Searching for it, however, is not an easy task because there are so many different ways it could manifest itself. As described in last week's Physics in a Nutshell, if supersymmetry exists, it can only be an approximate symmetry. Each model of broken supersymmetry predicts a different pattern of particles, their masses and their decay signatures. In a particle physics experiment, broken supersymmetry could look like just about anything.

How would you search for something that could look like anything? Fortunately, models of broken supersymmetry share a few broad features. For one thing, all of the models predict new particles, the superpartners of the ones we know. These would decay into familiar particles because they maintain part of their identity as they decay— for instance, supersymmetric quarks, called squarks, would decay to quarks. In many models, the lightest supersymmetric particle is invisible, like dark matter, which shows up in a particle collision as an apparent imbalance in the particle debris.

In a recent paper, CMS scientists used these as criteria in a broad search for new physics. They looked for an excess of collision events with many high-energy particles in a lopsided pattern, as though an invisible particle carried away much of the energy. They found nothing new— all was in agreement with known physics.

This result has far-reaching consequences. It rules out many of the simplest models of supersymmetry, but as described in last week's Nutshell, more subtle models lie beyond. It makes some headway into these non-minimal models because so few model-specific assumptions were made in the analysis. It's even general enough to address some non-supersymmetric theories, so the paper's authors present their result in a theory-neutral way.

Sometimes, the lack of an observation can be as exciting as a discovery. While this summer's discovery of a new massive boson was a marvelous achievement, it will confirm a widely held expectation if it turns out to really be the Higgs boson. On the other hand, the simple models of supersymmetry ruled out by this search were also widely expected, and now they are refuted.

—Jim Pivarski

The U.S. physicists pictured above were all major contributors to this analysis.
These are the U.S. members of the CMS Thesis Award Committee, which presents an annual award to one of the best Ph.D. theses in CMS.

Today's New Announcements

Pre-Retirement Planning Program - Aug. 22

Paddle boat tour - Aug. 23

Free weight management course - register by Aug. 24

Congratulations to Abri Credit Union winner

University of Chicago Tuition Remission Program deadline - today

Fermilab Triathlon - Aug. 18

Howard Levy & Chris Siebold - Aug. 18

English country dancing with live music - Aug. 19

Butts & Guts offered twice a week - begins Aug. 21

Zumba offered twice a week - begins Aug. 22

URA Visiting Scholars Program deadline - Aug. 27

Scottish country dancing in Ramsey Auditorium - through Aug. 31

International Folk Dancing in Ramsey Auditorium - through August

Project Management Introduction class - Sept. 10-14

Fermilab Management Practices Seminar - begins Oct. 4

Interpersonal communication skills training - Nov. 14

Outdoor soccer - Tuesdays and Thursdays at 6 p.m.

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