Friday, May 24, 2013

Have a safe day!

Friday, May 24

1:30 p.m.
LHC Physics Center Topic of the Week Seminar - WH11NE
Speaker: Natalia Toro, Perimeter Institute
Title: Closing the Door on Weak-Scale SUSY

3:30 p.m.

4 p.m.
Joint Experimental-Theoretical Physics Seminar - One West
Speaker: Ben Brau, University of Massachusetts, Amherst
Title: Dark Matter Inspired Exotics Searches with ATLAS

Monday, May 27

Memorial Day holiday

Tuesday, May 28

Undergraduate Lecture Series - Curia II
Speaker: Vladimir Shiltsev, Fermilab
Title: Accelerators

2:30 p.m.
Particle Astrophysics Seminar (NOTE DATE, TIME, LOCATION) - WH6NW
Speaker: Tim Eifler, University of Pennsylvania
Title: Constraining Cosmology and Dark Energy Models with Current and Future Wide-Field Imaging Surveys

3:30 p.m.


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a weekly calendar with links to additional information.

Ongoing and upcoming conferences at Fermilab


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Wilson Hall Cafe

Friday, May 24

- Breakfast: blueberry-stuffed French toast
- Breakfast: chorizo and egg burrito
- Bratwurst-cooked-in-beer sandwich
- Seafood linguine
- Barbecue chicken
- Barbecue pork spare ribs
- Turkey and cucumber salad wraps
- Strawberry summer salad with chicken
- Texas-style chili
- Vegetarian chili

Wilson Hall Cafe menu
Chez Leon

Friday, May 24
- Beef en croute with coriander walnut filling
- Fennel and potato gratin
- Haricots verts with red peppers and almonds
- Coffee creme brulee

Wednesday, May 29
- Fig- and chili-glazed pork tenderloin
- Whipped potatoes
- Steamed green beans
- Banana walnut upside-down cake

Chez Leon menu
Call x3524 to make your reservation.


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Physics in a Nutshell

Unity and symmetry

Apart from mass, the electromagnetic photon and the weak Z boson are the same particle—in two manifestations.

In this series of Physics in a Nutshell articles, Don and I have talked about each of the four fundamental forces of nature: electromagnetism, the strong force, the weak force and gravity. However, these four forces are not truly distinct. Many physicists are motivated by the idea that they are really four manifestations of a single principle, yet to be discovered. It's already clear that two of them, electromagnetism and the weak force, are related by a unifying principle, known as electroweak symmetry.

Perhaps the deepest idea in physics is Noether's Theorem, which states that symmetries in the laws of physics imply the existence of conserved quantities. For instance, the fact that an isolated experiment performed today would yield the same result as the same experiment performed tomorrow—time translation symmetry—is ultimately responsible for the conservation of energy. Since mass is a form of energy, this fact about the nature of time implies that matter is persistent and may be thought of as a substance.

Similarly, the conservation of electric charge is due to a symmetry. It is called gauge symmetry, and, if you're familiar with electronics, this is the reason that all voltages are measured relative to an arbitrary ground level. A circuit operating between 0 volts and 5 volts is the same as the circuit between 100 volts and 105 volts. When magnetism is added to the mix, gauge symmetry becomes more complicated, since you can trade electric voltages for magnetic potentials.

In the 1970s and '80s, physicists discovered that the weak force can also be added to the mix. The gauge symmetry of the weak force is much more complex than that of electromagnetism, but the two are actually factors of a single equation. An experimental consequence of this is that the photons of electromagnetism and the Z bosons of the weak force are really the same particle (or half-and-half mixtures of two fundamental particles, depending on how you want to look at it). A photon can behave like a Z boson and vice-versa, under the right circumstances.

However, the photon is massless and the Z boson is so massive that only a handful of high-energy accelerators have ever created them. If the symmetry were exact, they would both be massless. Since electric and weak charges do exist, it is widely believed that the laws of physics have electroweak symmetry, but something in the environment "breaks" the symmetry.

The Higgs mechanism is one possible explanation. This idea is that we are immersed in a field that interacts with Z bosons, giving them an effective mass. It is thus impossible to do a truly isolated experiment. Since the particle discovered last year seems to be the long-sought Higgs boson, we may finally be able to test this theory.

Perhaps electroweak unification is only the first step. It would be intellectually satisfying if all forces derive from a single principle, but more importantly, that principle would reveal the conservation laws that give rise to matter itself.

Jim Pivarski

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Special Announcement

Construction on AZero parking lot starting next week

Starting the week of May 27, the AZero parking lot will be affected by construction. The north section will be closed and the pedestrian walkway on the east side of the Main Ring berm will have occasional detours or be inaccessible. The duration of the closure and interruptions will last through the month of June.

Press Release

Run like a proton at Fermilab's new playground

Fermilab's new Run Like A Proton accelerator path at the Lederman Science Center is now open. Photo: Reidar Hahn

It's one thing for kids to try to envision particles zipping around underground when learning about the science at Fermilab. It's another thing entirely for them to pretend to be particles charging along an accelerator path, revealing new physics as they fly by.

This week the Fermilab Education Office celebrated the completion of its new Run Like A Proton accelerator path for middle- and high-school-age visitors to the laboratory.

Located at the Lederman Science Center, the path is an aboveground, scaled-down version of the routes a particle can take through Fermilab's accelerator complex. While running along the path, kids can act like they are the particles of the lab's physics program zipping through underground tunnels.

"Kids have different modes of learning," said Spencer Pasero of Fermilab's Education Office. "They can learn about the work of the lab with our indoor exhibits, but now they can also learn about it through our new outdoor playground."

Read more

In the News

Secretary Moniz leads DOE town hall

From, May 22, 2013

Editor's note: This article features a video of the May 22 town hall meeting.

"I have a lot of hope and aspirations for what we're going to accomplish here together."

So began Energy Secretary Ernest Moniz as he led a town hall discussion with Energy Department employees on his second day in office.

Read more

Frontier Science Result: MINOS

Unraveling neutrino oscillations with MINOS

This figure shows the allowed region for the neutrino oscillation parameters represented by the area inside the contour. The black contour is the result from MINOS using its combined data set of beam and atmospheric neutrinos and antineutrinos, where the star corresponds to the best fit to the data. We compare this with what we would get by analyzing the data set from beam neutrinos only, shown in red.

Neutrinos are among the most mysterious particles that make up the universe, and they are not very easy to study. The three types can change from one to another in a quantum phenomenon known as neutrino oscillations.

In the MINOS experiment, we are able to measure these oscillations by producing a beam made of muon neutrinos (the NuMI beam) and detecting it in two different locations: at the near detector, located at Fermilab, and at the far detector, 734 kilometers away in Soudan, Minn. The large distance between the detectors gives the neutrinos a chance to change type, allowing us to observe neutrino oscillations.

The MINOS experiment has the special feature of being able to detect muon neutrinos and antineutrinos individually by separating the events each produces. Therefore we are able to study both muon neutrino and antineutrino oscillations, which are described essentially by two parameters: mixing angle and mass splitting.

Beyond that, we also use the far detector to detect neutrinos and antineutrinos created by interactions of cosmic ray particles with the nuclei in the Earth's atmosphere. These are called atmospheric neutrinos and antineutrinos.

Several experiments have been measuring neutrino oscillations, helping us better understand this mysterious particle. For the first time, the MINOS collaboration has carried out a measurement by combining its two kinds of data: beam and atmospheric neutrinos and antineutrinos. We used the complete MINOS data set, accumulated over nine years of operation. The combined analysis has yielded the world's most precise measurement of the mass splitting parameter for both muon neutrinos and antineutrinos. Furthermore, we compared results obtained for muon neutrinos and antineutrinos and found that they have practically the same oscillation parameters, providing more evidence that CPT symmetry is conserved in the neutrino sector. This is also the most precise comparison ever made between neutrino and antineutrino oscillation parameters.

Learn more

—Michelle Medeiros

Here we can see by how much the mass splitting of the antineutrinos differs from the neutrinos, where the dashed line represents the hypothesis that the parameters are equal. The dot is the best fit to the combined MINOS data set: Δm2antineutrino - Δm2neutrino = [0.12 (+0.24) (-0.26)] x 10-3 eV2, which is consistent with neutrinos and antineutrinos having the same oscillation parameters.
Photo of the Day

Cloud of coral

Mike Becker, FESS, shot this lovely sunrise over Fermilab last week.
In Brief

New online menu and catering options

Fermilab's online food service menu was recently updated to include helpful nutritional information for most items offered in the Wilson Hall cafeteria. Southern Foodservice's certified nutritionist evaluates each recipe and determines nutritional information for the majority of meals offered at Fermilab each week.

While Southern's cooks and chefs usually follow Southern-endorsed recipes, they will occasionally incorporate local and new recipes that may not yet be in the recipe database. If a new item becomes popular and is added to the permanent menu, it will then be evaluated for nutritional information.

All of the updates and additions to Southern Foodservice's offerings, including a new catering menu, can be found on the iCafe website.


Today's New Announcements

Raging Waves water park discount

Fermilab Family Outdoor Fair - June 9

DASTOW scheduled - June 21

Fermilab prairie quadrat study

46th Fermilab Users Meeting registration now open

Register for Argonne-UChicago-Fermilab collaboration meeting

Bologna workshop in honor of Franco Rimondi

Summer Zumba

Swim lessons for children

Water fitness at Fermi Pool

Martial arts class

10,000 Steps participation winner

10,000 Steps-A-Day enrollment

Open gym basketball Tuesday evenings

Outdoor soccer at the Village

English country dancing at Kuhn Barn

Find new classified ads on Fermilab Today.