Thursday, April 17, 2014

Have a safe day!

Thursday, April 17

11 a.m.
Intensity Frontier Seminar Series - WH8XO
Speaker: Hogan Nguyen, Fermilab
Title: The Muon g-2 Experiment

3:30 p.m.

4 p.m.
Accelerator Physics and Technology Seminar (NOTE DATE) - One West
Speaker: Tom Kobilarcik, Fermilab
Title: The Booster Neutrino Beamline

4 p.m.
LHC Physics Center Topic of the Week Seminar (NOTE DATE) - WH11NE
Speaker: Greg Landsberg, Brown University
Title: New Developments in Dark Matter Searches at Colliders

Friday, April 18

3:30 p.m.

4 p.m.
Joint Experimental-Theoretical Physics Seminar - One West
Speaker: Tracy Slatyer, MIT
Title: Characterizing a Potential Dark Matter Signal in γ-Rays from the Central Milky Way

Click here for NALCAL,
a weekly calendar with links to additional information.

Ongoing and upcoming conferences at Fermilab


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Wilson Hall Cafe

Thursday, April 17

- Breakfast: Canadian bacon, egg and cheese Texas toast
- Breakfast: sausage gravy omelet
- Cajun chicken sandwich
- Smart cuisine: finger-lickin' baked chicken
- Mom's meatloaf
- Eggplant parmesan panino
- Greek chicken salad
- Meatball and orzo soup
- Chef's choice soup
- Assorted pizza by the slice

Wilson Hall Cafe menu

Chez Leon

Friday, April 18

Wednesday, April 23
- Grilled teriyaki shrimp kebobs
- Couscous
- Sugar snap peas
- Coconut flan

Chez Leon menu
Call x3524 to make your reservation.


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Justin Evans awarded Institute of Physics' High Energy Particle Physics Group Prize

Justin Evans

The UK-based Institute of Physics recently awarded the 2014 High Energy Particle Physics Group Prize to Justin Evans of the University of Manchester.

The prize is awarded to Evans "for his world-leading contributions to the measurement of neutrino oscillations at MINOS using the Fermilab NuMI beam."

The High Energy Particle Physics Group Prize is given for outstanding contributions to particle physics. It is intended to recognize physicists early in their careers, specifically in the first 12 years of a research career following the award of a first degree.


Dmitri Denisov re-elected DZero co-spokesperson

Dmitri Denisov

Last month Dmitri Denisov was re-elected for a two-year term as co-spokesperson for the DZero collaboration.

It is a renewal of a commitment that Denisov has made since 2006, when he was first elected. He will continue to lead DZero alongside Gregorio Bernardi.

DZero's 400 collaboration members come from 19 countries.

"That Dmitri is continuing as co-spokesperson is a guarantee of success for DZero's next steps," Bernardi said. "It's rare that a big collaboration can count on such a commitment. All of us at DZero are thankful for this."

Having participated on DZero since 1987, when he was a graduate student, Denisov was there at the experiment's beginning — even before the detector came online in 1992. Now he works to ensure that the legacy of DZero, as well as of the Tevatron, is thoroughly documented.

The Tevatron turned off in 2011, but there is still plenty of physics to be mined among 500 trillion proton-antiproton collisions it delivered to scientists for more than 20 years. Denisov will oversee the publication of many upcoming fundamental results from the data DZero collected. Through these publications and in cooperation with scientists from the Tevatron's other experiment, CDF, Denisov plans to help make accessible to scientists as much as possible of the physics the Tevatron helped to uncover.

"The Tevatron program shaped experimental particle physics for more than two decades, allowing us to make fundamental discoveries and precise measurements and growing a new generation of scientists," Denisov said. "Our work now is to fully extract physics results from the Tevatron data set and to preserve the DZero experiment data for the long term."

Leah Hesla

Video of the Day

Big mysteries: dark energy

Scientists were shocked in 1998 when they learned the expansion of the universe wasn't slowing down as expected but speeding up. CMS Education and Outreach Coordinator Don Lincoln talks about the observations that led to the hypothesis of dark energy and the status of current research on this mysterious phenomenon. View the video. Video: Fermilab
Photo of the Day

Rainbow erupts over Feynman

If you were lucky enough to be looking in the direction of the Feynman Computing Center on the early evening of April 7, you might have seen a rainbow shooting out of the building. Photo: Elliott McCrory, AD
In the News

Searching high and low for dark matter

From The Kavli Foundation, April 2014

Editor's note: Fermilab's Dan Hooper is one of the three scientists featured in this edited interview transcript.

There's more to the cosmos than meets the eye. In late February, dark matter hunters from around the world gathered at the University of California, Los Angeles for "Dark Matter 2014." The annual conference is one of the largest of its kind aimed at discussing the latest progress in the quest to identify dark matter, the unknown stuff that makes up more than a quarter of the universe yet remains a mystery. Nearly 160 people attended, including renowned physicists from institutions across the United States and Europe, as well as from Japan, China and Canada.

So where does the hunt stand? Between sessions, three leading physicists at the conference spent an hour discussing its biggest highlights and prospects for future progress.

Read more

In the News

Big bang to little swoosh

From The New York Times, April 11, 2014

CAMBRIDGE, Mass. — The shock waves are still reverberating from the bombshell announcement of the discovery of cosmology's holy grail: telltale signature of ripples in the very fabric of space generated as it "inflated" during our cosmic origins.

Read more

Frontier Science Result: DZero

Most precise single measurement of the top quark mass

The DZero experiment this week released the single most precise measurement of the top quark mass ever made. This plot shows the favored region for the top mass (the x-axis) and an important experimental parameter kJES (the y-axis) which is extracted simultaneously to improve the overall precision.

Disponible en español

Just four weeks ago in this column we featured the world combination of top quark mass measurements, which used as ingredients the set of best measurements from both Tevatron and LHC experiments available in February 2014. Far from indicating that we've reached the end of top quark analyses at DZero and CDF, this represents just a single snapshot of a continually developing program. As a perfect illustration, the DZero experiment this week released a new measurement of the top quark mass in the lepton-plus-jets channel, which is the most precise single measurement ever made and which is actually competitive with the world average itself.

The lepton-plus-jets channel is probably familiar to regular readers. The analysis reconstructs top quark-antiquark pairs in their decays into four quark jets, a charged lepton (an electron or muon) and missing momentum consistent with an undetected neutrino. This signature is distinctive enough to be distinguished from most backgrounds, but it also provides a sufficiently large sample with which to reach the required statistical precision on the top mass. Effectively, once the sample composition has been determined, the mass of the top (or antitop) quark can be extracted by appropriately adding the energies of the six decay products, which of course is much easier said than done.

Reaching the desired precision requires pushing our understanding of the DZero detector to its limit. In particular, with four quark jets in the final state, it is crucial to understand the correspondence between the measured signals and the true jet energies. This analysis uses some advanced techniques to help achieve this goal. Since all the top quark decays involve an intermediate W boson, we can use the existing precise measurements of the W boson mass to constrain the properties of the final jets, lepton and neutrino. Doing this provides enough additional information to make an independent jet energy calibration in situ, rather than relying on the existing calibrations, which relate the measured and true jet energies.

Using this method, the final analysis reports a two-dimensional measurement of the top quark mass and a jet energy scale factor kJES, as shown in the figure above. This method allows every last drop of information to be squeezed from the data and significantly reduces the dominant source of systematic uncertainty on the final measurement.

The upshot of this two-dimensional approach is a measured top quark mass of 174.98 GeV, with a total uncertainty of just 0.76 GeV, or less than half a percent. For reference, the world combination of the top mass, which does not include this new measurement, also has an uncertainty of 0.76 GeV. It is an impressive achievement that this single measurement can achieve the same precision as the recent worldwide combination and gives a taste of things to come. The era of high-precision top quark measurements is well and truly here.

Mark Williams

These DZero members all made significant contributions to this publication.
The DZero style council reads, checks and reviews every single paper submitted for publication to ensure that it is accurate and its text and figures pass rigorous quality requirements. This important and time-consuming effort ensures that the scientific results are propagated to the global community in a clear and accessible way.

Today's New Announcements

SharePoint for contributors (end users) - April 18

SharePoint designer training - April 18

SharePoint site owner introductory training - April 18

Three-on-three basketball tourney - starts May 1

Service Desk Web interface upgrade - today

Cross-step waltz workshop with dance historian - April 19

Zumba Toning registration due April 22

Pre-retirement planning Lunch and Learn - April 23 and May 7

Earth Week Fair - April 24

Fermilab Time and Labor URLs changing

On sale now: Fermilab Natural Areas hats and shirts

A Smart Cuisine purchase earns you 10 bonus points

2014 Fermilab Golf League season is upon us

Wednesday Walkers

Scottish country dancing meets Tuesday evenings at Kuhn Barn

International folk dancing meets Thursday evenings at Kuhn Barn

Indoor soccer