Friday, June 5, 2015
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Annual domestic hydrant flushing - June 6-7

Fermilab pool open June 9, memberships available

Managing Conflict (half-day) on June 10

Commercializing Innovation: office hours at IARC - June 11

International folk dancing Thursday evenings through June 11

NALWO lecture: Beauty of Barns - June 16

art/LArSoft course at Fermilab, free registration - Aug. 3-7

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From symmetry

The universe at your fingertips

Raw images from the DECam Legacy Survey's new image archive will appear online the day after they are taken. Photo: DECam Legacy Survey

When it was time to celebrate the 20th anniversary of the Star Wars trilogy, director George Lucas was prompted by technological leaps in the filmmaking industry to produce a digitally remastered special edition.

[On Thursday] scientists of the DECam Legacy Survey released their own version of a special edition. They published the first in a series of catalogs that offer an update to images of the night sky originally taken with the 15-year-old camera of the Sloan Digital Sky Survey.

In the spirit of the new information age, the survey will share frequent updates on its public website. With its Sky Viewer, users can explore the contents of the universe, whose busyness might surprise anyone accustomed to bland skies polluted by city lights.

Site visitors can choose whether they want to look at false-color images or theoretical models of the sky, or see the difference between the two. The website also contains a map of dust emissions in the Milky Way based on data first reported in one of the most cited journal articles of all astrophysics.

Similar exploration tools exist for the image archives of SDSS and the Hubble telescope. However, these data became publicly available only after a period of restricted use by a limited group of researchers.

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Manuel Gnida

Video of the Day

Joint Speaker Series: Science and Sound

Science and Sound is the eleventh in a series of Joint Speaker events for Argonne, Fermilab and University of Chicago scientists, scholars, researchers, engineers and their guests. The event took place on June 3 at Buddy Guy's Legends. Fermilab and University of Chicago scientist Bradford Benson, who works on investigations of the cosmic microwave background, was one of the speakers. View the seven-minute video. Video: University of Chicago Research
Photo of the Day

Snap of a snapper

Is this snapping turtle pausing to pose? Or does having its picture taken leave it shellshocked? Photo: Mauricio Lopes, TD
In the News

The Mu2e experiment: a rare opportunity

From CERN Courier, June 2, 2015

The Mu2e experiment at Fermilab recently achieved an important milestone, when it received the US Department of Energy's critical-decision 2 (CD-2) approval in March. This officially sets the baselines in the scope, cost and schedule of the experiment. At the same time, the Mu2e collaboration was awarded authorization to begin fabricating one of the experiment's three solenoids and to begin the construction of the experimental hall, which saw ground-breaking on 18 April. The experiment will search with unprecedented sensitivity for the neutrinoless conversion of a muon into an electron.

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Frontier Science Result: CMS

Heavy neutrinos

Heavy neutrinos are proposed cousins of the familiar light neutrinos. The masses of the heavy and light neutrinos are connected: the heavier the heavy ones are, the lighter the light ones are. This connection is called the seesaw mechanism.

With the discovery of the Higgs field, scientists think they have a pretty good handle on the origins of the mass of fundamental particles. Particles that interact with the field have mass, and those that don't, don't. However, the neutrino poses an additional mystery. Neutrinos have a very tiny mass, but not zero. Just why this should be is not known.

One very popular idea is that there is another kind of neutrino, a heavier kind of neutrino. In the theory, the masses of the ordinary neutrinos and heavy neutrinos are tied together. If one gets big, the other gets small. For this reason, the theory is colloquially called the seesaw mechanism. Heavy neutrinos have not been observed.

So naturally, CMS scientists went digging through their data to see if there was any evidence that heavy neutrinos were real. These searches hinge on the fact that neutrinos, both heavy and light, are a type of a particle called a Majorana particle in this theory. The defining characteristic of a Majorana particle is that it is its own antiparticle. An earlier Fermilab Today article describes this in more detail.

This analysis looked for a peculiar event signature, one in which two muons of the same charge are formed. Today's analysis is a follow-on of an earlier one also described in Fermilab Today. In the earlier article, I explained how Majorana neutrinos and two muons of the same charge are related. (Plus that article has a very cool graphic. Check it out!)

No evidence for heavy Majorana neutrinos was found, and CMS physicists used the measurement to set very strict limits on the range of possible masses for heavy Majorana neutrinos that are still allowed. As CMS resumes operations at 13 trillion electronvolts, physicists will study the new data, looking for even higher masses. You should expect another article on this subject in a couple of years, hopefully with a discovery!

Don Lincoln

These physicists contributed to this analysis. (Ferdinando Giordano is now a postdoc at INFN/Catania.)
These U.S. scientists are making crucial contributions to simulations to develop and design a future tracking trigger system for the high-luminosity LHC.
In the News

The neutron and proton weigh in, theoretically

From Physics Today, June 2015

The mass difference between the neutron and proton — about 0.14 percent — is known experimentally with an impressive precision of 4 parts in 10 million. But calculating that difference from scratch via quantum chromodynamics (QCD), the theory of the strong force, is another matter altogether.

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