Friday, March 15, 2013

Have a safe day!

Friday, March 15

3:30 p.m.

4 p.m.
Joint Experimental-Theoretical Physics Seminar - One West
Speaker: Yurii Maravin, Kansas State University
Title: Highlights from Recent CMS Results

8 p.m.
Fermilab Lecture Series - Auditorium
The Believers: A Science Documentary
Tickets: $7

Monday, March 18

2:30 p.m.
Particle Astrophysics Seminar - One West
Speaker: Greg Dobler, University of California, Santa Barbara
Title: From Hazes to Bubbles: an Enormous Eruption from the Heart of the Milky Way

3:30 p.m.


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Wilson Hall Cafe

Friday, March 15

- Breakfast: Irish omelet
- Irish beef stew
- Irish dip
- Corned beef and cabbage
- Smart cuisine: Irish chicken and dumplings
- Ham and cheese on green bread
- Assorted pizza
- Irish nachos

Wilson Hall Cafe Menu
Chez Leon

Friday, March 15
- Mussels with white wine and thyme
- Grilled lamb chops
- Mushroom risotto
- Pear tart

Wednesday, March 20
- Ham and gruyere crepes with madeira sauce
- Cabbage salad
- Chocolate fondue

Chez Leon Menu
Call x3524 to make your reservation.


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Physics in a Nutshell

Sacks and boats:
subatomic forces

At the subatomic level, forces appear because one matter particle emits a force particle. When you throw a heavy sack off a boat, the boat recoils. Similarly, when one particle emits another one, the original particle recoils (moves). This is fundamentally how forces work at the subatomic level. Image courtesy of Dan Claes

Read the complete column on subatomic forces.

Particle physicists explore the subatomic realm, which consists of quarks, leptons and the four forces that govern them. These forces are the strong nuclear force, the electromagnetic force, the weak nuclear force and gravitational force.

Over the next few weeks, we will be describing each of these forces and how they behave. Today we'll look at some commonalities to understand what particle physicists mean when they use the term "force" and what we know about how these forces behave in the microworld.

The word force has a technical meaning in an introductory physics class. According to Newton's laws, a force changes the velocity of an object. Hitting the accelerator or brake pedal in your car will cause it to speed up or slow down. Each of these two actions, therefore, applies a force to the car. You can also change the velocity by changing direction. By turning the steering wheel of your car, you can make the car move left or right through the force between the tires and the road.

However, in everyday usage, the term force refers to something that can bring about change not just in velocity, but in general. An example is a military force toppling a government, inducing a change in the country's politics. When describing the forces between subatomic particles, particle physicists use a more general meaning like this one. While forces can certainly alter the trajectory of a particle or change its energy, they can also cause particles to combine, decay or change their identities. Thanks to subatomic forces, a photon can disappear and an electron and antimatter electron can appear in its place. In the subatomic world, forces induce many kinds of change.

A class of theories called quantum field theories, or QFTs for short, describes the way that forces are induced in particle collisions. A basic property of these theories is that they replace the force fields of classical physics with quantum fields. For instance, in the quantum field formulation, Earth's gravitational field is treated as having lots of tiny force-carrying particles buzzing around. By way of analogy, think of air. We know what air is like—it's everywhere. However, we also know of air molecules, which can be considered quanta of air. The QFT approach focuses on the "atoms" of the force.

Read more

Don Lincoln

Want a phrase defined? Have a question? E-mail


APS recognizes Tanaji Sen

Tanaji Sen

The American Physical Society has recognized Fermilab physicist Tanaji Sen for his outstanding contributions as a referee for APS journals. The list of recognized scientists also includes Fermilab's Bill Bardeen.

The APS Outstanding Referee program was instituted in 2008 to recognize scientists who have been exceptionally helpful in assessing manuscripts for publication in the APS journals. The highly selective program annually recognizes about 150 of the roughly 60,000 currently active referees. Like fellowship in the APS, this is a lifetime award. In 2013, 142 Outstanding Referees were selected.

To see a list of all APS Outstanding Referees, visit the program website.

In the News

The sequester is going to devastate U.S. science research for decades

From The Atlantic, March 12, 2013

Editor's note: National laboratory directors Paul Alivisatos (Berkeley National Laboratory), Eric D. Isaacs (Argonne National Laboratory) and Thom Mason (Oak Ridge National Laboratory) wrote this article.

Most of the talk about sequestration has focused on its immediate impacts—layoffs, furloughs, and cancelled White House tours in the days and weeks ahead. But one severe impact of the automatic spending cuts will only be felt years—or even decades—in the future, when the nation begins to feel the loss of important new scientific ideas that now will not be explored, and of brilliant young scientists who now will take their talents overseas or perhaps even abandon research entirely.

Read more
In the News

Space station to host new cosmic ray telescope

From UChicago News, March 6, 2013

The National Aeronautics and Space Administration has awarded $4.4 million to a collaboration of scientists at five United States universities and NASA's Marshall Space Flight Center to help build a telescope for deployment on the International Space Station in 2017.

Read more
Frontier Science Result: MINOS

Does matter matter for neutrino flavor?

By combining its neutrino and antineutrino data sets, MINOS has constrained the non-standard interaction parameter εμτ, finding that the results are consistent with εμτ=0, shown by the gray line. The angle θ and the parameter Δm2 relate to the relative masses of the neutrinos and to how quantum mechanically "mixed" the flavors are.

The NuMI (Neutrinos at the Main Injector) beam is generated here at Fermilab and points toward the Soudan Underground Laboratory in Soudan, Minn. The MINOS collaboration detects this beam of neutrinos in its journey twice: once at Fermilab right after it is generated and once at Soudan Lab after the neutrinos have traveled 450 miles through the Earth's crust. At its generation, the beam is made up of muon-flavored neutrinos (neutrinos come in three flavors: electron, muon, and tau). After traveling such a long distance, some of the neutrinos change flavor, primarily into tau neutrinos and a few into electron neutrinos. This phenomenon of flavor change is called neutrino oscillation. By counting the number (and measuring the energy) of muon neutrinos before and after travel, MINOS can measure parameters that govern neutrino oscillations.

The presence of matter in the neutrino path may also have an impact on flavor change. If it does, the flavor count after travel would be altered. Some of these interactions are expected from the tiny number of oscillation-generated electron neutrinos, but extra interactions of muon or tau neutrinos with the Earth are non-standard and are thus called non-standard interactions, or NSI for short. (The Earth is made up of regular matter—electrons, protons and neutrons—and not of matter in muon or tau flavors.)

NSI affects neutrinos and antineutrinos in opposite ways, whereas most of the standard oscillations are expected to be the same for both. Thanks to NuMI's ability to generate separate neutrino and antineutrino beams and to the magnetized detectors' ability to discriminate neutrino and antineutrino interactions, MINOS can search for non-standard interactions and measure the NSI parameter called εμτ. In this new analysis, MINOS combined its neutrino and antineutrino data collected over five years and performed the first direct search for NSI. The results showed that NSI made no significant contribution to flavor change, in agreement with previous hints.

Because of its magnetized detectors, MINOS remains the most suitable experiment to further investigate NSI. Starting this spring, MINOS+ will collect data in a complementary energy regime. This will allow for a more precise determination of the impact of NSI in neutrino flavor change.

—Zeynep Isvan, Brookhaven National Laboratory

Photo of the Day

Happy St. Patrick's Day

Julie Kurnat, TD, made this chalk drawing for St. Patrick's Day. You can view the drawing in Trailer 157.

Today's New Announcements

Main Ring Road closed - March 18-19

Fermilab Lecture Series: The Believers (documentary) - today

Healthcare spending account deadline - today

C2ST: Investing in Innovation for the Future - March 21

Employee Art Show reception - March 22

Job Descriptions and Employment class - March 22

Fermilab Arts & Lecture Series: ScrapArtsMusic - March 23

DOEGrids certificates to be decommissioned - March 23

School's Day Out camp - March 25-29

Nominations open for 2013 Tollestrup Award - through April 1

Hiring managers: submit summer personnel requisitions by April 12

The World According to Higgs - Chris Quigg - April 12

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

Fermilab Management Practices courses now available for registration

Walk 2 Run

Scottish country dancing meets Tuesday evenings in Kuhn Barn

Monday golf league

Indoor soccer

Find new classified ads on Fermilab Today.