Thursday, Jan. 10, 2013

Have a safe day!

Thursday, Jan. 10

2:30 p.m.
Theoretical Physics Seminar - Curia II
Speaker: Claudia Frugiuele, Fermilab
Title: R Symmetry as the Lepton Number

3:30 p.m.

4 p.m.
Accelerator Physics and Technology Seminar - One West
Speaker: Mary Convery, Fermilab
Title: Muon Campus Plans

Friday, Jan. 11

3:30 p.m.

4 p.m.
Joint Experimental-Theoretical Physics Seminar - One West
Speaker: Rolf Ent, Thomas Jefferson National Accelerator Laboratory
Title: Probing the Quark Sea and Gluons: The Electron-Ion Collider Project

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Wilson Hall Cafe

Thursday, Jan. 10

- Corned-beef hash and eggs
- White-chicken chili
- Monte cristo
- 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, Jan. 11
Guest chefs: Grace and Gary Leonard
- Pear, blue cheese and walnut salad
- Cocoa crusted pork tenderloin
- Potato cakes
- Haricots verts
- Blueberry upside-down cake with cream chantilly

Wednesday, Jan. 16
- Balsamic glazed salmon
- Roasted new potatoes
- Brussels sprouts
- Lemon cheesecake

Chez Leon Menu
Call x3524 to make your reservation.


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In Brief

Don't let the warm weather fool you - watch for black ice

Avoid slipping on black ice: watch where you walk.

Recent weather conditions have provided plenty of opportunity for the formation of black ice, a thin, transparent layer of ice on concrete or asphalt. Watch out when walking and driving on site. People have slipped in recent days.

The cold nighttime temperatures freeze water that has pooled during the daylight hours. Although much of the ice melts in the next day's warmth, patches of ice unexposed to the sun remain behind, creating a hazard for those unaware that not all the ice has melted away.

"During this season, people really have to watch where they're going," said Jack MacNerland, FCC building manager. "Just because ice thaws during the day, it doesn't mean it's not going to refreeze during the later hours."

To avoid slipping on black ice, follow these tips:

  • Use footwear that provides traction on snow and ice.
  • Hang onto railings or other stable objects. Use your vehicle for support when entering or exiting.
  • Use designated clear walkways or a grassy edge.
  • If you must walk on ice, take short steps or shuffle. Bend slightly and walk flat-footed with your center of gravity over your feet.
  • Be prepared to fall. If it happens, bend your back and head forward. Fall with sequential contacts at your thigh, hip and shoulder.
  • If you encounter a spot of black ice at Fermilab near a building entryway, look to see if there is sand or salt inside the door to put on it, should it need it.
  • If there is no sand or salt nearby, and if the patch of black ice is in a place of traffic—even if it is not near a building entryway—contact the building manager or your SSO to let him or her know of your concern.
Photo of the Day

After Beauvais

Cathedral-like Wilson Hall soars upward. Photo: Reidar Hahn
In the News

Muon-capture measurement backs QCD prediction

From Physics World, Jan. 9, 2013

The rate at which protons capture muons has been accurately measured for the first time by the MuCap collaboration at the Paul Scherrer Institute (PSI) in Switzerland. This process, which can be thought of as beta decay in reverse, results in the formation of a neutron and a neutrino. The team has also determined a dimensionless factor that influences the rate of muon capture, which was found to be in excellent agreement with theoretical predictions that are based on very complex calculations.

Muons are cousins of the electron that are around 200 times heavier. Beta decays demonstrate the weak nuclear force in which a neutron gets converted into a proton by emitting an electron and a neutrino. Now, replace the electron with the heavier muon and run the process backwards: a proton captures a muon and transforms into a neutron while emitting a neutrino. This process—known as ordinary muon capture (OMC)—is crucial to understanding the weak interaction involving protons.

Read more
In the News

Crystals aim to light up dark matter

From Chemistry World, Jan. 9, 2013

German scientists hunting dark matter are set to produce half a tonne of high-purity calcium tungstate for their detectors, one 1kg crystal at a time. The CRESST-II experiment based in Gran Sasso, Italy is currently seeking this enigmatic substance, thought to explain the universe's structure, with 10kg of calcium tungstate (CaWO4). Now Andreas Erb and Jean-Côme Lanfranchi are preparing crystals for its larger successor EURECA, which will begin operation in the French Alps in 5–10 years.

Read more
Frontier Science Result: CDF

Editor's note: Starting this year, Fermilab Today will bring you more results from research at the Energy, Intensity and Cosmic Frontiers. We will publish these results on Thursdays and Fridays, highlighting the full breadth of Fermilab's experiments.

An important vertex

In the Standard Model, the top quark almost always decays to a W boson and a b quark as shown in this diagram. The specifics of the tWb interaction at the decay vertex affect the kinematics of the W boson and b quark. So by measuring these kinematics in the CDF II detector, we can learn something about the physics at the tWb vertex.

The top quark was first observed in the Tevatron Run I (1992-1996) data sets collected by the CDF and DZero experiments at Fermilab. Because the mass of the top quark is large, beyond-the-Standard Model physics contributions can affect the top quark phenomenology in a wide variety of ways: The way it is produced can be affected; the way it decays can be affected; its intrinsic properties can be changed; or new particles can mimic a top quark decay and confuse our experimental measurements. Thus a principal goal of the Tevatron Run II (2001-2011) program, which produced data samples 100 times larger than Run I, was to explore thoroughly the properties of the top quark. Recently the CDF collaboration submitted a paper for publication that describes a measurement of top quark decays that uses the full Run II data set and is sensitive to potential new physics contributions affecting the top quark in a variety of ways.

At the Tevatron, top quarks are predominantly produced in pairs and are predicted to almost always decay into a W boson and a b quark (see top figure). The object of this measurement is to test the physics of the top-W-bottom (tWb) decay vertex in detail.

Other quarks, which are much lighter than the top quark, have longer lifetimes and interact with other quarks before decaying. These additional interactions complicate our efforts to understand the physics at the decay vertex. But the top quark is a different story. Because of its very large mass and therefore its very short lifetime—a trillionth of a trillionth of a second—the top quark does not have enough time to interact with other particles and thus decays as a "bare" quark. So the top quark decays used in this analysis provide very clean tests in which to measure the physics of the tWb vertex and compare it to Standard Model predictions.

The methodology used is similar to the one employed in our previous version of this analysis, which used only 2.7 inverse femtobarns of CDF data. The current analysis is based on a data sample that's about three times larger and yields the most precise single-channel measurement to date from the Tevatron. Alas, the data are fully consistent with the Standard Model predictions and indicate that the tWb vertex behaves just the way we thought it did. Future insights are expected from similar measurements at CDF using different top quark final states, from DZero and from the LHC experiments ATLAS and CMS.

Learn more

edited by Douglas Glenzinski and Andy Beretvas

These CDF physicists contributed to this data analysis. From left: Doug Glenzinski (Fermilab) and Mousumi Datta (Fermilab and Hampton University, Hampton, Va.).

Today's New Announcements

Indoor soccer

USA Athletic Club and Spa discount for employees

2013 FRA scholarship application deadline - April 1

NALWO presents Travelogue of Southeast Asia - today

Fermilab Lecture Series - Building Bionics - Jan. 18

Gallery Chamber Series - Metropolis Quartet - Jan. 20

Fermilab Arts Series - Tomas Kubinek - Jan. 26

January 2013 timecards and float holiday

Zumba offered Tuesdays and Fridays

Fermilab Management Practices courses available for registration

International Folk Dancing Thursday evenings in Kuhn Barn

Martial arts classes

Employee discounts on AAA membership