Thursday, May 24, 2012

Have a safe day!

Thursday, May 24
2:30 p.m.
Theoretical Physics Seminar - Curia II
Speaker: Lian-Tao Wang, University of Chicago
Title: (Over) Interpreting the Higgs "signal"
3:30 p.m.

Friday, May 25
3:30 p.m.
4 p.m.
Joint Experiment-Theoretical Physics Seminar - One West
Speaker: Jonathan Feng, University of California, Irvine
Title: Naturalness and the Status of SUSY

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Thursday, May 24
- Breakfast: Apple sticks
- Minnesota wild rice w/ chicken
- Tuna melt on nine-grain bread
- Smart cuisine: Italian meatloaf
- Chicken casserole
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- Smart cuisine: Mandarin chicken salad

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Friday, May 25
- Romaine & watercress salad w/ Roquefort buttermilk dressing
- Grilled marinated London broil
- Yellow bell pepper orzo gratin
- Roasted zucchini & red onion
- Minted berry sponge cakes

Wednesday, May 30
- Andouille & chicken creole pasta
- Mixed greens
- Banana cream pie

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45th Users' Meeting highlights results, looks to the future

This year's Fermilab Users' Meeting will cover new experiment results, the latest in the laboratory's forward-looking projects and presentations from leaders of the scientific policy community. The meeting, which takes place on June 12-13, will cover topics in the fields of collider, astroparticle, and neutrino physics and will give Fermilab users and employees the opportunity to learn more about the laboratory's plans for the future.

"We have a full program that will include the most recent physics results and reports on future projects," said Users' Meeting Subcommittee Chair Lisa Whitehead. "We hope to have a lot of grad students and postdocs participating in the meeting again this year."

On June 14 Fermilab's Graduate Student Association will holdits New Perspective Conference, a day of talks given by undergraduate, graduate and post-doctoral students. The group will also host a poster session during the two-day Users' Meeting.

One highlight of the meeting will be a presentation by Jim Siegrist, director of the Office of High Energy Physics in the DOE Office of Science.

Nobel laureate David Gross will also give a public lecture on what it means to have a final theory of fundamental physics. His talk takes place at 8 p.m. on Tuesday, June 12, in Ramsey Auditorium. Tickets are available through the Fermilab Arts and Lecture Series.

"Fermilab has exciting plans for future experiments that will continue to bring us even closer to an understanding of the fundamental make-up of our world," said Daniel Kaplan, Users' Executive Committee Chair. "The Users' Meeting is a good time to get acquainted with them."

Registration for the event is free.

—Leah Hesla

Special Announcement

Undergraduate Lecture Series begins next Tuesday

Fermilab's Undergraduate Lecture Series starts up next week. The summer series, organized by the Equal Opportunity and Diversity Office, is open to all students interning at the laboratory.

The lectures take place on Tuesdays at noon in One West.

Vladimir Shiltsev will give the first talk, an introduction to accelerators.

For more information, visit the Undergraduate Lecture Series website.

Special Announcement

Ecology bus tour - June 1

Take a guided tour of Fermilab's natural hidden gems and lesser-known habitats. The next Ecology Lunch Bus Tour, led by Ryan Campbell, takes place on June 1 from noon to 1 p.m.

Space is limited to 15 passengers. Please RSVP to Ryan Campbell at

In the News

Like attracts like?

From Nature, May 23, 2012

Everything you thought you knew about electrostatics is probably wrong.

Make two metal spheres positively electrically charged, bring them close together, and what happens? They'll repel one another, because like charges repel – right?

Wrong. According to physicist John Lekner at the Victoria University of Wellington in New Zealand, they will most probably attract one another, violating the intuitions of basic physics. The counterintuitive result was published today in the Proceedings of the Royal Society A.

Read more

In the News

Disentangling the wave-particle duality in the double-slit experiment

From ars technica, May 21, 2012

Photons act like they go through two paths, even when we know which they took.

The subtlest experiment in quantum mechanics is also one of the simplest: send a stream of particles through two openings in a barrier, and you'll produce an interference pattern because the particles act as waves. Amazingly, this also works if you send the particles through one at a time—the interference pattern builds up slowly as more particles go through. The double-slit experiment has been replicated with photons, electrons, atoms, and even entire molecules.

Typically, the particle nature and the wave nature have to be observed separately; if you track the particles through a single slit, the interference pattern vanishes. However, Ralf Menzel, Dirk Puhlmann, Axel Heuer, and Wolfgang P. Schleich entangled two photons and allowed one to pass through a barrier with two slits. The entanglement enabled them to determine which opening the photon went through, but a detector on the other side still picked up an interference pattern, demonstrating light's wave- and particle-like characteristics simultaneously.

Read more

Result of the Week

W-spin measured in a low-
background environment

The signal templates for left-handed, longitudinal and right-handed W bosons together with the background template for the dilepton selection.

One of the phenomena CDF studies is the production of top and anti-top quark pairs. The top quark decays almost immediately into a W boson and a bottom quark. Thus in a top-anti-top event, two Ws are produced – one from each quark. The W is identified by its subsequent decay into an electron or a muon and a neutrino. The neutrino is not directly identified because it does not interact in the detector. However, the event's missing energy is a sign that a neutrino was produced.

This relatively rare decay of top and anti-top into muons or electrons, two neutrinos and two bottom quarks, known as a top dilepton event, can be reconstructed.

The top quark, a relatively massive particle, has a particular spin state. When it first decays into a W and a bottom, it transfers its spin properties to the W since, between it and the bottom quark, the W is far heavier.

From the reconstruction we determine the rotational states of the W, of which there are three possibilities. They are the right-handed state, where the motion of the W particle and its spin are in the same direction; left-handed, where the motion of the W particle and its spin are in the opposite direction; and longitudinal, where the motion of the particle and its spin are perpendicular. The fractional probabilties of these three spin states must add up to one. Any given W can exist in only one state. What is measured is essentially the angle between the direction of the momentum of the lepton  - the decay electron or muon - and that of the top quark in the W boson's rest frame (see figures).

The comparison of the cos ϑ* distribution between data and the expected Standard Model top + anti-top signal and background.

Using 5.1 inverse femtobarns of data we find the probability that a W is observed in a longitudinal rotational state is 71 +18/-17%. The right-handed fraction is -7 ± 9%. We further find that at the 95% confidence level that the right-handed fraction is less than 7%.

This is in very good agreement with the Standard Model prediction of a longitudinal fraction of 69.8% and a right-handed prediction of essentially zero (3.7 x 10-4).

Learn more

—edited by Andy Beretvas

These physicists were responsible for this analysis.

First row from left: Jaroslav Antos (Institute of Experimental Physics, Kosice, Slovakia), Andy Beretvas (Fermilab), Yen-Chu Chen (Academia Sinica, Taipei, Taiwan)

Second row: Soo-Bong Kim (Seoul National University, Korea), Roman Lysak (Institute of Experimental Physics, Kosice, Slovakia), Chang-Seong Moon (Seoul National University, Korea)


Electrical safety table in atrium - today

NALWO luncheon and tour - today

Fermilab Family Outdoor Fair - June 10

Swim lessons for adults, youth & preschoolers - register by June 11

Tevatron symposium - June 11

Fermilab Users' Meeting - June 12-13

New Perspectives is coming - June 14

University of Chicago Tuition Remission Program deadline - June 15

Adult water aerobics - begins June 18

DreamWeaver CS5: Intro class - June 19-20

DASTOW - June 20

Intermediate/advanced Python programming class - June 20-22

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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Join Walk 10,000 Steps-A-Day

Scottish country dancing meets Tuesday evenings in Kuhn Village Barn

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Changarro restaurant offers 15 percent discount to employees

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