Friday, Dec. 7, 2012

Friday, Dec. 7

3:30 p.m.

4 p.m.
Joint Experimental-Theoretical Physics Seminar - One West
Speakers: Michael Begel, Brookhaven National Laboratory
Title: Recent ATLAS SUSY Results

Saturday, Dec. 8

8 p.m.
Fermilab Arts Series - Auditorium
Good Lovelies Holiday Show
Tickets: $23/$12

Monday, Dec. 10

2:30 p.m.
Particle Astrophysics Seminar - One West
Speaker: Yookyung Noh, University of California, Berkeley
Title: Filamentary Environment and Mass Measurements of Galaxy Clusters

3:30 p.m.


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Wilson Hall Cafe

Friday, Dec. 7

- Breakfast: French bistro breakfast
- New England clam chowder
- Becks-battered-fish sandwich
- Tortellini alfredo
- Smart cuisine: herb and lemon fish
- Cuban panini
- Assorted pizza by the slice
- Szechuan green beans with chicken

Wilson Hall Cafe Menu
Chez Leon

Friday, Dec. 7
- Mushroom soup with chorizo and scallions
- Pecan-crusted beef tenderloin
- Cauliflower gratin
- Brussels sprouts with lemon and bacon
- Chocolate mousse pie

Wednesday, Dec. 12
- Shepherd's pie
- Field greens with cranberries and walnuts
- Cocoa cappuccino mousse with cookies

Chez Leon Menu
Call x3524 to make your reservation.


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From symmetry

Complex simulations: a driving force for LSST

The Large Synoptic Survey Telescope, the world's largest sky survey, will rain a monsoon of data onto the astrophysics community. Simulations prepare scientists for the approaching storm. Image: Sandbox Studio

Almost a decade remains before the Large Synoptic Survey Telescope sees first light, and construction has yet to begin on most of the telescope's hardware. Even so, astrophysicists are already developing methods for analyzing the rush of data LSST will produce. In a survey this large and this advanced, data management is just as important as cameras and mirrors.

From atop Cerro Pachón ridge in Chile, LSST will conduct the world's most ambitious astronomical imaging survey yet. Astronomy surveys have been generating catalogs of data since the 1940s. They help scientists study the universe on a large scale and collect vast amounts of data more quickly than it would take with individual observations. LSST will compile a catalog that dwarfs all current survey catalogs combined.

A tribute to advanced technology, the telescope's powerful camera will capture light from objects 100 times fainter than those observed in any current survey, giving scientists a peek into the earliest developmental stages of the universe. The unique, triple-mirror system will scan the entire southern sky in three nights, faster than any other telescope. And each night, the telescope will collect about 15 terabytes of data. The Sloan Digital Sky Survey, the largest optical survey to date, took 10 years to gather the same amount.

All of this data will allow scientists to create a detailed three-dimensional map of our universe and address four main science goals: to explore dark energy, to investigate galactic structure, to monitor objects' movements on short timescales and to track near-Earth asteroids.

To handle the gargantuan quantity of data from the moment the telescope first turns on around 2020, a complex system of computer simulations is already well underway. The system has three principle components: the Image Simulator, which will produce mock LSST images to anticipate image quality; the Operations Simulator, which will predict the optimal viewing schedule each night; and the Calibrations Simulator, which will calculate the true brightness of objects to ensure accurate science. Combined, the simulators will help scientists get as much science as possible from LSST data.

For astrophysicists, the LSST simulators are more comprehensive than any before. Such sophisticated simulations were, until recently, primarily used in particle and high-energy physics research.

"In a particle accelerator, you have a gazillion particles coming out with jets, tracks and lots more," says Fermilab scientist and LSST collaborator Scott Dodelson. "Similarly with LSST, things are becoming very crowded as we go deeper, so we need sophisticated algorithms to even be able to identify what a galaxy is, and we need to test these algorithms with simulations."

Each simulator serves a different purpose, but all are inherently connected and necessary for LSST's future success.

Read more

Jessica Orwig

Special Announcement

Main Ring Road closed Monday

Main Ring Road will be closed between the AZero Service Building and F-4 Service Building on Monday, Dec. 10, from 7 a.m. to 5:30 p.m. The detour route for accessing the AZero parking lot will run counterclockwise from the intersection at Main Ring Road and Booster Road.

In the News

Ancient gas sheds light on universe's first billion years

From Physics World, Dec. 5, 2012

For the first time, astronomers have determined the chemical composition of gas from the first billion years of the universe's life. The gas consists mostly of neutral hydrogen atoms, which means that it may mark the era before stellar radiation began ionizing the universe. Furthermore, the gas shows no signs of the heavy elements that are forged in stars so it may contain only the light elements produced by the Big Bang.

"We are starting to look back to the epoch that is probably when the first stars were turning on," says Robert Simcoe, an astronomer at the Massachusetts Institute of Technology who built the instrument that acquired the spectrum of the far-off gas. "This is the very first [chemical] measurement that anybody has made in any environment at these early times."

Read more
In the News

Case study: CERN adopts OpenStack private cloud to solve big data challenges

From Computer Weekly, Dec. 6, 2012

The Large Hadron Collider (LHC), which aims to answer fundamental questions of the universe's existence, is one of CERN's most important projects. But as the LHC produces 1PB of data every second, big data and lack of computing resources were becoming the European Organisation for Nuclear Research's biggest IT challenges.

The IT team has been using the open source OpenStack-based private cloud environment in the testing and development stage.

Read more
Physics in a Nutshell

A mixed bag of neutrinos

If we represent electron neutrinos (νe), muon neutrinos (νμ), and tau neutrinos (ντ) by pure red, pure green and pure blue, respectively, the three neutrino mass states (ν1, ν2 and ν3) would be fuchsia, lime and periwinkle, a mixture of the primary colors.

Quantum mechanics is an everyday fact of life for particle physicists. Most particles are short-lived and decay before they can be directly observed, and the weirdest quantum shenanigans are perpetrated by systems that can't be observed. Neutrinos behave quantum mechanically, and even though they are not short-lived, neutrinos are so difficult to observe that they can maintain a mixed quantum state even while traveling large distances.

A quantum state—the current value of some aspect of a quantum system—is like a light switch. It can be off or on, but never in between. Before discovering quantum mechanics, physicists expected a system's properties to be like dimmer switches that smoothly slide between off and on, but they're not. In addition, quantum properties can also take on multiple values simultaneously—off and on, as illustrated by the figure below. Each possible state contributes some amount, such as 30 percent off and 70 percent on. This mixing allows neutrinos to spontaneously change from one type to another, a phenomenon known as neutrino oscillations.

Neutrinos are categorized by how they they are produced: Electron neutrinos are produced along with electrons, muon neutrinos along with muons and tau neutrinos along with tau particles. They can also be categorized by mass: Neutrino 1, neutrino 2 and neutrino 3 all weigh different amounts. A neutrino cannot be categorized by production mode and by mass at the same time, however. A pure production state is a quantum mixture of all three mass states and a mass state is a quantum mixture of all three production states. A muon neutrino, produced along with a muon in the LBNE beamline for instance, would travel for hundreds of miles from Fermilab as a mixture of quantum states and may be observed in a detector in South Dakota as an electron neutrino.

This interplay between production states and mass states is what allows neutrinos to oscillate, or change from one production state to another and back again. The probability of each state actually wavers back and forth, the way the pitch of a gong wobbles as it resounds. The gong wobbles with a beat frequency because of a competition between two nearly matched resonances, which are analogous to the differences between neutrino masses in neutrino oscillations.

Physicists use production state transitions to learn more about the neutrino mass states. Neutrino masses are so small that it's hard to measure them any other way, though they have cosmic significance. There are enough neutrinos in the universe that their feeble masses could affect how galaxies form and how space expands. The exact way that production states and mass states mix might even be associated with the disappearance of antimatter in the early stages of the Big Bang.

—Jim Pivarski

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

A classical (pre-quantum) system can take any single value between off and on, while a quantum system can be off, on or both, but never in between.

Today's New Announcements

Budker Seminar - Dec. 10

Register for 10-minute meetings with Director Search Committee

The Good Lovelies: Under the Mistletoe - Dec. 8

Barn Dance - Dec. 9

Fermilab Heartland Blood Drive - Dec. 10-11

AFS passwords to be discontinued - Dec. 11

Clearance through customs (also streamed live) - Dec. 13

Fermilab's Holiday Celebration - Dec. 13

School's Out Day Camp - register by Dec. 19

Holiday stress relief massages - Dec. 20

An Honest Approach to Weight Management - register by Dec. 21

Service Desk staffing hours have been extended

Revised Procedures for Researchers document online

Professional development courses

International Folk Dancing every Thursday through December

Indoor soccer

Give the gift that everyone can use!

Employee discounts at Journey Cycle and BMX

Atrium work updates

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