Friday, Aug. 29, 2014

Have a safe day!

Friday, Aug. 29

3:30 p.m.

4 p.m.
Joint Experimental-Theoretical Physics Seminar - One West
Speaker: Sanjay Padhi, University of California, San Diego
Title: Next Steps in the Energy Frontier - Hadron Colliders

Monday, Sept. 1
Labor Day holiday

Tuesday, Sept. 2

2:30 p.m.
Theoretical Physics Seminar (NOTE DATE, LOCATION) - WH3NW
Speaker: Adrian Carmona, ETH Zurich
Title: Lifting Top Partners at the LHC

3:30 p.m.


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Wilson Hall Cafe

Friday, Aug. 29

- Breakfast: Penalty flag breakfast turnover
- Breakfast: chorizo and egg burrito
- End zone beer-braised brats
- Smart cuisine: white fish florentine
- Overtime barbecue chicken
- Kickoff club sandwich
- Big game boneless wings
- Touchdown Wisconsin beer and cheese soup
- Texas-style chili
- Assorted pizza by the slice

Wilson Hall Cafe menu

Chez Leon

Friday, Aug. 29

Wednesday, Sept. 3
- Spinach- and feta- stuffed portobello mushrooms
- Poppy seed fruited slaw
- Blackberry crumb cake

Chez Leon menu
Call x3524 to make your reservation.


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Physics in a Nutshell

Invisibility squared

The former presence of a cat on the patio can be inferred from where the rain didn't land. Similarly, sterile neutrinos may be inferred from their effects on normal neutrinos, which themselves are barely visible.

What does it mean for something to be invisible? If it does not reflect light with the right wavelengths, it is not visible to humans, though it might be detected by a specialized instrument. Neutral particles, such as the neutrons in an atom, do not interact with photons of any wavelength (unless the wavelength is small enough to resolve individual charged quarks within the neutron). Thus, they are invisible to nearly every instrument that uses electromagnetic radiation to see.

However, neutrons are easy to detect in other ways. They interact through the strong and weak nuclear forces, and neutron detectors take advantage of these interactions to "see" them. Neutrinos, on the other hand, are still more invisible, since they have no constituent quarks and interact only through the weak force. Billions of neutrinos pass through every square centimeter per second, but only a handful of these per day are detectable in a room-sized instrument.

Now suppose there were another kind of neutrino that did not interact with the weak force. Physicists would call such a particle a sterile neutrino if it existed. How could it be detected? If something can't be detected, does it even make sense to talk about it? Could there be a whole world of other particles, filling the same space we do, that can never be detected because they don't interact with anything that interacts with our eyeballs?

In principle, anything that has mass or energy can be detected because it interacts gravitationally. That is, if there were a sterile neutrino planet right next to the Earth, then it would change the way that satellites orbit: This is our gravitational detector. However, a small mass, such as an individual particle, would deflect orbits so little that it could not be detected in practice.

Although sterile neutrinos would have no effect on ordinary matter, they could be detected through what they do to other neutrinos. Neutrinos of different types mix quantum mechanically. That is, muon neutrinos created by a muon beam can become electron neutrinos and tau neutrinos when they are detected. If there were a fourth, sterile, type of neutrino, then the visible neutrinos would also partly transition to sterile neutrinos in flight and change the fractions of the three visible types of neutrinos in the detector.

In the mid-1990s, an experiment called LSND saw what looked like a sterile neutrino signal, so MiniBooNE, an experiment at Fermilab, studied the effect in more detail. As the MiniBooNE scientists investigated, the story got weirder: the numbers of visible neutrinos didn't add up, but at different energies than expected. No simple explanation makes sense of the data, but it is possible that a sterile neutrino might. A future experiment, MicroBooNE, will study this phenomenon with higher sensitivity. It would be impressive if the key to new physics is an invisible particle, glimpsed only through its effect on nearly invisible particles!

Jim Pivarski

Video of the Day

Got a minute? Turning collisions into numbers

It might be obvious, but a crucial step in understanding our universe is to take physical properties, for instance energy and position, and to quantify them. Once the results have been quantified, we can then turn to powerful mathematical tools to better understand what is going on. Scientist Titas Roy helps us understand this better. View the video. Video: U.S. CMS
Photo of the Day

Sweeping the sky

Monday's long shelf cloud, seen near the C4 service building on the Tevatron ring. Image: Marty Murphy, AD
In Brief

New features on latest version of Scientific Linux website

The new Scientific Linux website rolled out this week.

The new Scientific Linux website, which rolled out Aug. 26, boasts a robust new architecture.

The scalable design will allow Scientific Linux developers to continue to identify opportunities for automation so that they are delivering the freshest news, updates and content. The Fermilab Scientific Linux team has already integrated aspects of the development workflow for automatic posting of updates. It has also introduced a blog to provide insight into the developers' technical and philosophical thoughts and ideas.

The team views these new website features as just the beginning in our renewed focus to further grow the Scientific Linux collaboration with other international institutions.

In the News

Jim Nowlan: Fermilab looking into the smallest things

From The Daily Journal, Aug. 22, 2014

As I scribble a note for this column, I am standing 350 feet underground at a research experiment that is sending beams of trillions of neutrinos underground to a detector located 500 miles away in Minnesota.

I am at the Fermi National Accelerator Laboratory (Fermilab) in west suburban Chicago, where Big Science — and big achievements — are the hallmark of the sprawling lab.

Read more

In the News

A physics experiment might soon tell us if we're living in a 2D hologram

From The Verge, Aug. 26, 2014

For all we know, the three dimensional world we see around us is really an illusion — one that's actually in 2D. It's a slightly unsettling idea, but it's also one that physicists have been thinking about for some time. Unfortunately, until recently, a 2D universe wasn't something we could verify. Now, thanks to an experiment recently launched at Fermi National Laboratory in Illinois, we might finally be able to determine how the universe stores the information we interact with everyday — and whether we're living in a hologram.

Read more

Frontier Science Result: ArgoNeuT

20 years later: Neutrino-induced coherent pions are back to Fermilab

Display of an event captured in the ArgoNeuT detector. The track on the top corresponds to a muon, the one below it is a charged pion. These particles are produced by the interaction of a muon neutrino with an argon atom in the detector.

The neutrino is known for how rarely it interacts with matter. But when it does, the interaction can take place numerous ways, and some interaction types happen more often than others. The ArgoNeuT experiment recently looked at one of the more rare cases — one that comes to only about 1 percent of all the possible ways a neutrino can interact. As one might expect, its infrequency poses a great challenge in our efforts to measure it.

This month, the ArgoNeuT collaboration released a new measurement of this rare interaction, called charged-current coherent pion production induced by neutrinos on nuclei. In this process, a neutrino interacts with a nucleus as a whole, producing a muon and a pion without breaking the nucleus apart or leaving it in an excited state. Seen in the detector, the events look like the one shown above, where two very forward-going tracks leave the interaction point.

Historically, there have been only a handful of experiments that observed coherent pion production. Back in 1993, the FNAL E632 experiment, conducted using a 15-foot bubble chamber, measured interactions of this type at a neutrino energy of 70 to 90 GeV. In more recent years, the K2K and SciBooNE experiments also attempted to measure this cross section at a much lower energy (1 to 2 GeV) but found no sign of it in the charged-current channel. The null results motivated renewed interest by the theoretical community, who modified the favored models of the time and proposed new ones.

These days, Fermilab's ArgoNeuT and MINERvA collaborations are in hot pursuit of these interactions, measuring them using the low-energy NuMI beam. The ArgoNeuT collaboration has measured the likelihoods of charged-current pion production, reporting the interactions with neutrinos and antineutrinos at the mean energies of 3.6 GeV and 10 GeV, respectively. These measured probabilities, the results of a five-month run of antineutrino-enhanced NuMI beam, are in good agreement with theoretical predictions and are attracting much interest within the neutrino community.

This is the first time that scientists measured the process in a liquid-argon detector and using an automated reconstruction. Researchers also once again demonstrated the potential of the liquid-argon technique for the measurement of neutrino interactions. Key pieces of this success were ArgoNeuT's capabilities for precisely measuring the particles ejected from a neutrino interacting with an argon nucleus.

Although ArgoNeuT's small detector size limits the precision of this measurement, the techniques developed during this analysis will be used by future, larger experiments, such as MicroBooNE and LAr1-ND, to gain new insights into coherent pion production.

Edward Santos, Imperial College London, and Tingjun Yang, Fermilab

Learn more

The primary authors of this result are Tingjun Yang of Fermilab, left, and Edward Santos of Imperial College London.
Special Announcement

Power outage in Wilson Hall east tower Tuesday morning

On Tuesday, Sept. 2, there will be a 10- to 20-minute power outage between 7 a.m. and 7:30 a.m. in Wilson Hall. The entire east tower of Wilson Hall will be affected, including portions of the north and south crossovers on every floor.

Please turn off all electronic equipment by the end of the day today.

Routine electrical service will be offline for the duration of this outage. Only elevator cars 1, 2 and 4 will be available during this brief outage.

Emergency and exit lights will be operational during the outage.


Patent on magnetic oil spill cleanup apparatus

On July 30, 2014, Fermilab Today reported on an invention by Fermilab physicist Arden Warner that could lead to more efficient and environmentally friendly cleanup of oil spills. Because of the wide interest in the invention and some confusion about the scope of the patent, we offer the following clarification.

US Patent No. 8,795,519 was issued on Aug. 5, 2014, for an "electromagnetic boom and environmental cleanup application for use in conjunction with magnetizable oil."

Although Warner was not the first inventor to consider the idea of magnetizing oil to improve oil collection and recovery, his invention for using an electromagnetic boom apparatus is new and novel. Fermilab is interested in licensing the technology to a company that is interested in developing, demonstrating and commercializing the technology.

We would like to acknowledge the accomplishments of other inventors who have developed technologies that use magnetism to recover oil from water. While there are too many inventions and inventors to list them all here, we would like to extend a special mention to George Nicolaides, who originally filed for patent protection of a "new magnetic, porous and oleophillic copolymer used for oil spill cleanup and oil recovery from the sea and the environment" in 1997 in Greece.


Road closure on Main Ring Road - today and tomorrow

Walk 2 Run offers two time slots in August

Scottish country dancing Tuesdays in auditorium through Sept. 2, then at Kuhn Barn

Art gallery talk - Sept. 3

International folk dancing Thursdays at auditorium through Sept. 4, then at Kuhn Barn

English country dancing Sunday afternoon at Kuhn Barn - Sept. 7

Users Executive Committee election voting deadline Sept. 8

NBI 2014 Workshop - Sept. 23-26

Bowlers wanted

Outdoor soccer

Batavia Smashburger employee discount

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