Wednesday, March 25, 2015
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Wilson Hall southwest stair work: temporary access restriction through April 4

Pilates registration due March 30

2015 FRA scholarship applications accepted until April 1

2015 URA Alvin Tollestrup Award application deadline - April 1

Nominations for Employee Advisory Group due April 17

2014 FSA deadline is April 30

Interpersonal Communication Skills course - May 20

Mac OS X security patches

SharePoint online training videos available for on-site users

Fermilab Board Game Guild

Muscle Toning class

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Fermilab Golf League 2015 season is just around the corner

Changarro restaurant offers Fermilab employee discount


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From symmetry

Physics Madness: The Supersymmetric Sixteen

Which physics machine will reign supreme? Your vote decides. Image: Sandbox Studio

March is here, and that means one thing: brackets. We've matched up 16 of the coolest pieces of particle physics equipment that help scientists answer big questions about our universe. Your vote will decide this year's favorite.

The tournament will last four rounds, starting with the Supersymmetric Sixteen today, moving on to the Elemental Eight on March 27, then the Fundamental Four on March 31 and finally the Grand Unified Championship on April 3. The first round's match-ups are below. You have until midnight PDT on Thursday, March 26, to vote in this round. May the best physics machine win!

View the brackets

Lauren Biron

Photos of the Day

Winter returns

If this picture looks familiar, perhaps it's because you viewed the same scene in an apparently different season in the March 17 Photo of the Day. What a difference a few days makes. Photo: Tom Nicol, TD
Monday's snowfall blanketed the Wilson Hall parking lot three inches deep. Spring has begun, yet it is still too early to put away the snow shovels. Photo: Lynn Garren, SCD
The snow didn't faze the burly bison. Photo: Lori Limberg, ESH&Q
In the News

Short circuit in magnet delays Large Hadron Collider's restart

From NBC News, March 24, 2015

A short circuit in one of the Large Hadron Collider's eight magnet sectors will delay the restart of the world's most powerful particle accelerator, Europe's CERN particle physics center announced Tuesday.

The LHC was due to start recirculating beams of protons this week, in preparation for the resumption of science operations after a two-year shutdown for upgrades. However, an intermittent short was identified in one of the machine's magnet circuits on March 21, and that will need to be investigated before the beam is turned on, CERN said. It said the investigation could take days or weeks — depending on whether the supercooled sector needs to be warmed up, repaired and then cooled back down.

"Any cryogenic machine is a time amplifier, so what would have taken hours in a warm machine could end up taking us weeks," Frederick Bordry, CERN's director for accelerators, said in Tuesday's statement.

Read more

From the Center for Particle Astrophysics

Building a dark matter radio

Craig Hogan

Craig Hogan, head of the Center for Particle Astrophysics, wrote this column.

You may have heard lately that the famous cosmic dark matter — the mysterious new kind of stuff that makes up most of the gravitational mass of the universe — may not, in fact, be completely dark, but may actually emit small amounts of light. That would be very exciting, because we might detect the light and use it to help figure out what the stuff is made of.

For example, the Fermi Gamma-Ray Space Telescope detects light, in the form of photons from the center of our galaxy, that may be caused by massive dark matter particles annihilating each other. Such high-energy photons can be created if the individual dark matter particles themselves are massive— much more massive than any known stable particle.

But it's also possible that the dark matter particles have extraordinarily low mass — even smaller than the tiny masses associated with neutrinos. In that case, the light emitted by dark matter, if any, would not show up as high-energy gamma rays; instead, it would show up as radio waves. Indeed, even the dark matter itself acts more like a coherent oscillating wave field than a collection of individual particles. In this situation, the best way to search for them may not be a traditional particle detector but a receiver more like a radio.

A leading candidate for this kind of dark matter is called an axion. The existence of such a field was predicted long ago, not from a need for dark matter, but as a way to explain why strong interactions (the quantum chromodynamics of the Standard Model that control the structure of atomic nuclei) do not appear to distinguish the past from the future as the other interactions do. In standard cosmology, if such a particle has a low mass, roughly in the microwave range of radio frequencies, it could be produced in sufficient abundance to be some, or even all, of the cosmic dark matter.

If so, we might find them in the laboratory. It turns out that if cosmic axions from our galaxy pass through a strong magnet, they give off a small amount of radio light at exactly the frequency corresponding to their tiny mass. To detect them, we want to build a radio tuned to that mass. The radio in this case uses a highly resonant cavity, similar to those that Fermilab uses all the time to accelerate particles. We don't know the mass of the axion exactly, so to search for the axion, we have to tune the radio — the cavity — until we get a signal.

The Axion Dark Matter Experiment has started a search like this at the University of Washington. (Because the experiment is not sensitive to cosmic rays, the actual apparatus does not have to be deep underground, but is on campus.) The tuning starts at low frequencies, searching for axions of relatively low mass, where it can use relatively large cavities. But there is a long way to go: Theory provides only a rough guess about the mass of the axion, and nobody yet knows exactly how to build smaller cavities that can efficiently search for higher-mass axions.

Fermilab scientists and engineers are planning to make unique contributions to state-of-the-art higher-frequency cavity designs for the higher-mass search, drawing on their years of experience with radio-frequency cavities in accelerators. This unique fusion of accelerator science and dark matter science is an exciting example of the synergy that happens at Fermilab.

Safety Update

ESH&Q weekly report, March 24

This week's safety report, compiled by the Fermilab ESH&Q Section, contains one incident.

An employee sustained an abrasion on his left knee after slipping in the parking lot. It was snowing heavily at the time. The employee received first-aid treatment.

See the full report.