Thursday, Aug. 7, 2014

Thursday, Aug. 7


3:30 p.m.

Friday, Aug. 8

3:30 p.m.


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Wilson Hall Cafe

Thursday, Aug. 7

- Breakfast: Canadian bacon, egg and cheese Texas toast
- Breakfast: sausage gravy omelet
- Italian combo sandwich
- Smart cuisine: finger-lickin' baked chicken
- Mom's meatloaf
- Rosemary chicken with sun-dried tomatoes
- Greek chicken salad
- Meatball and orzo soup
- Chef's choice soup
- Assorted pizza by the slice

Wilson Hall Cafe menu

Chez Leon

Friday, Aug. 8

Wednesday, Aug. 13
- Baked southwest chicken with jack cheese and peppers
- Frijoles
- Mexican rice
- Apricot pecan tartlets

Chez Leon menu
Call x3524 to make your reservation.


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LBNE collaboration expands to more than 500 members

The LBNE collaboration met at Fermilab last week. Photo: Cindy Arnold

The Long-Baseline Neutrino Experiment, with more than 500 collaborators, is now the largest neutrino experiment collaboration in the world. In his opening address at last week's collaboration meeting at Fermilab, LBNE co-spokesperson Robert Wilson reported that LBNE now counts 527 members from 90 institutions, including 139 from 35 institutions in eight non-U.S. countries. There were 159 registered participants at the July collaboration meeting, the largest attendance LBNE has enjoyed to date.

Based on recommendations from the recent P5 report, a process to form a new fully internationalized collaboration to be called the Long-Baseline Neutrino Facility has begun. During this transition, the collaboration will continue to operate and grow as LBNE to maintain continuity as the new organization evolves. Members of LBNE will make up a major part of LBNF.

"As the reformulation process takes place, we look forward to helping establish a project that fulfills the vision of a world-class neutrino experiment," said Milind Diwan, LBNE co-spokesperson.

The growth of LBNE continues a many-year trend in high-energy physics toward fewer and larger experiments. As the scale and complexity of new projects continues to grow, larger numbers of scientists are needed to carry out the design of the experiment and the analysis of the data. Other large neutrino physics collaborations include T2K and IceCube, with recent author lists of 326 and 302, respectively. Daya Bay, Double Chooz, ICARUS, MicroBooNE, MiniBooNE, MINERvA, MINOS, NOνA and RENO each number between 40 and 200.

It is likely that more than 1,000 people will work on the new experiment, a prediction based on the growth of MINOS and NOvA from this point in their history, and particularly given the fact that many students and postdocs will join at a later stage, when physics data is likely to be collected. The largest collaborations in high-energy physics are the CERN experiments ATLAS and CMS, which currently have about 3,000 scientists each.

"The accelerator-based neutrino communities worldwide have been growing. They have convinced the larger particle physics community that a combined short- and long-baseline neutrino program is rich in physics and worth major investments," Fermilab Director Nigel Lockyer told the LBNE collaboration. "The Department of Energy and Fermilab are working together for success, and international funding agencies are at the table. This is an unparalleled opportunity to establish a united international collaboration for long-baseline neutrino physics based at Fermilab."

Maury Goodman, LBNE deputy spokesperson

Photo of the Day

Grazing in the grass

It sure is mellow grazing in the grass. Photo: Sarah Witman
In the News

Particle Fever makes me feel like a physicist

From Gizmodo, Aug. 1, 2014

Editor's note: The University of Chicago will host a free screening of Particle Fever on Tuesday, Aug. 26, at 6:30 p.m. Fermilab Deputy Director Joe Lykken and scientist Marcela Carena of Fermilab and the University of Chicago will be among the speakers at a post-screening Q&A session.

Understanding the inner workings of existence is a challenge not everyone is equipped for. In my high school physics class, I learned a handful of Newtonian laws and something about a quark, and that was about it. But during Particle Fever's 120-minute runtime, I felt like a physicist.

The documentary centers around the discovery of the Higgs boson, one of the biggest moments in physics' millennia-long history. Physicist-turned-documentarian Mark Levinson interviewed experimentalists at CERN, capturing several amazing milestones in science, and also a collection of U.S.-based theorists. The stakes? Well, before the Large Hadron Collider smashed subatomic particles into its own miniature Big Bang, physics as a discipline was at a crossroads. Two prevailing theories — supersymmetry and multiverse — hinged on the existence of the Higgs boson.

Read more

Frontier Science Result: CDF

Sifting through the noise to identify single top quarks

Results of the two-dimensional fit for σ(s) and σ(t+Wt). The black circle shows the best-fit value, and the 68.3 percent, 95.5 percent and 99.7 percent credibility regions are shown as shaded areas. The Standard Model (SM) predictions are also included with their theoretical uncertainties.

CDF and DZero discovered the top quark in 1995 from proton-antiproton collisions that produced the top quark together with its antimatter partner, the antitop quark. It took 14 more years for the same collaborations to announce the observation of a top or antitop quark produced without the other. Why the long delay? The main reason has to do with the features of events with only one of the massive quarks. Single-top events are remarkably similar to other more common types of events, and the lack of a clear separation between the single-top signal and other backgrounds made it very difficult to tease it out.

In this single-top quark analysis at CDF, we selected events with the following characteristics: a lepton (either an electron or a muon) with high transverse energy; a large imbalance of transverse momentum, which indicates the presence of a neutrino; and two or three jets, at least one of which must originate from a bottom quark. The two main backgrounds are a W boson plus a bottom or charm jet and a W boson plus an up, down or strange jet. Other backgrounds include a Z boson plus jets, top-antitop pairs, two-boson events and events in which a jet has been misidentified as an electron or a muon.

After applying event selection requirements, we found that the sum of the backgrounds was still about 15 times larger than the signal. Thus, we needed a thorough understanding of the backgrounds to bring the signal to the fore. The solution was to use a set of artificial neural networks. Using a few variables that describe the properties of the events, such as the reconstructed top quark mass and the transverse mass of the reconstructed W boson, we trained the neural networks to separate the signal from the backgrounds. This process is similar to how neurons in our brain work when we engage in pattern recognition. After applying the artificial neural networks in our analysis, we measured a single-top quark cross section of 3.04 +0.57/-0.53 picobarns.

There are three processes for the production of single top quarks: s-channel, t-channel and associated Wt production. An important feature of this measurement is that we use a next-to-leading-order event generator for the first time to properly include the Wt contribution. In addition to the combined single-top cross section, we also extract separate values for the s-channel process and the sum of the t-channel + Wt processes, as shown in the figure above. The measurements are fully compatible with predictions of the Standard Model.

edited by Andy Beretvas

Learn more

These CDF physicists contributed to this data analysis. Top row from left: Giorgio Chiarelli (INFN, University of Pisa) and Jay Dittmann (Baylor University). Second row: Dominic Hirschbuehl (Bergische Universitaet Wuppertal, Germany), Sandra Leone (INFN, University of Pisa), Jan Lueck (Karlsruhe Institute of Technology, Karlsruhe, Germany). Third row: Manfredi Ronzani (INFN, University of Pisa) and Zhenbin Wu (Baylor University).

Today's New Announcements

Fermilab Lecture Series presents The Science of Speed - Aug. 15

Town hall meetings on changes to videoconferencing - today; Aug. 28

C++ FNAL Software School - through Aug. 8

English country dancing Sunday afternoon at Kuhn Barn - Aug. 10

Deadline for the UChicago tuition remission program - Aug. 18

Call for applications: URA Visiting Scholars Program - apply by Aug. 25

Adobe Flash Player update on Windows

New central web services launched

Walk 2 Run offers two time slots in August

International folk dancing Thursday evenings at Ramsey through August

Scottish country dancing Tuesday evenings at Ramsey through August

Fermilab Tango Club