Thursday, March 20, 2014

Have a safe day!

Thursday, March 20

11 a.m.
Intensity Frontier Seminar Series - WH8XO
Speaker: Alex Sousa, University of Cincinnati
Title: Planning for Future Neutrino Experiments

2:30 p.m.
Theoretical Physics Seminar - Curia II
Speaker: André Walker-Loud, College of William and Mary
Title: Mn-Mp

3:30 p.m.

Friday, March 21

3:30 p.m.

4 p.m.
Joint Experimental-Theoretical Physics Seminar - One West
Speaker: Felix Sefkow, DESY
Title: Imaging Calorimeters: The New Look of Hadrons

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, March 20

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

Wilson Hall Cafe menu

Chez Leon

Friday, March 21
- Mixed greens with herb vinaigrette
- Fig and chili-glazed pork tenderloin
- Potato cakes
- Sauteed green beans
- Pecan rum cake

Wednesday, March 26
- Chipotle-honey-glazed salmon
- Green rice
- Sugar snap peas
- Cold lemon souffle

Chez Leon menu
Call x3524 to make your reservation.


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Sending GENIE into the neutrino community

Neutrino physicists from around the world met at Fermilab to learn the GENIE code. Photo: Reidar Hahn

When most people hear the word "genie," they get ready to make a wish. When neutrino physicists hear it, they think of a simulation program the community uses to study the ghostly particles.

Last week more than a dozen physicists visited Fermilab for a meeting of the collaboration behind GENIE. As one of the few places with expertise in the software, Fermilab served as a hub for the user community where students and postdocs came to be trained in the program.

Steering clear of slide shows, scientists at the GENIE collaboration meeting spent the week hunched over various laptops, working on adding new physics models and options to the code.

"With GENIE, we're attempting to understand and help resolve issues confronting the next generation of experiments at the Intensity Frontier," said GENIE spokesperson Costas Andreopoulos of the University of Liverpool and STFC's Rutherford Appleton Laboratory. "We appreciate the effort by Fermilab to host this."

GENIE is an event generator — a program that spits out different particle event scenarios based on the interaction model that's fed to it. In particular, GENIE simulates interactions between a neutrino and a target atom. Scientists use event generators to better understand signals in their detectors. By comparing predictions from well-understood physics, they can isolate new phenomena.

GENIE isn't the only neutrino-event generator out there, but it's the only one that's universal: It can handle all neutrino species, all types of interaction targets and all energy ranges. Other neutrino event generators — home-grown project-specific programs focused on a particular neutrino physics model — can't be used to explore possibilities beyond that model. When Andreopoulos and others developed GENIE — which stands for Generates Events for Neutrino Interaction Experiments — from 2004 to 2006, they designed it to be applicable to any kind of neutrino interaction.

"We aimed to produce a design that allows you to put multiple models into the generator," Andreopoulos said. "That flexibility wasn't there from the beginning in other neutrino-event generators."

And whereas with other comparable software, only scientists on the project in question can provide input, anyone conversant in GENIE can contribute to its development.

"A large number of people can contribute to GENIE," said Fermilab's Gabriel Perdue, main organizer of the workshop. "It's like a crowd-sourcing tool for the neutrino set, so it's superior for large-scale collaboration compared to other similar programs."

GENIE serves the entire neutrino community, but only a handful of scientists have strong expertise in it. So representatives from diverse experiments — IceCube, LBNE, MicroBooNE, MINERvA and T2K — convened at the Fermilab meeting to learn the program. Steve Brice, head of Fermilab's Intensity Frontier Department, hopes that soon its use will become widespread.

"With the workshop, this code can go from being a small-scale project with two or three developers to something that's prevalent in the user community," Brice said. "With so many new people on neutrino physics from so many collaborations, we can expect great progress on some difficult problems in neutrino interaction simulations."

Leah Hesla


In memoriam: Simon Kwan

Simon Kwan

Our dear friend and colleague Simon Kwan passed away on March 14 at age 62 after a two-year struggle with lung cancer.

Simon felt passionately that developing new and innovative detectors was critical to the health of high-energy physics. He taught in several instrumentation schools and organized workshops and conferences. He collaborated with many companies to develop new technologies. He was a long-standing member of RD50, a collaboration to develop radiation-hard sensors.

Simon received his doctorate at University of Bristol on experiment NA32. NA32 used charge-coupled devices as vertex detectors to provide precision reconstruction of charm decays. The use of silicon pixels at the much higher collision rates and radiation levels of today's colliders became the central theme of Simon's research.

Simon joined Fermilab in 1989 and spent his early years studying charm production using hadrons in two experiments, E769 and E791, which relied heavily on pioneering silicon vertex detectors.

Simon next took on a daunting challenge for a new experiment, BTeV, designing of a silicon pixel detector that could survive the high radiation levels of the Tevatron's powerful colliding beams and that could be used in the first-level trigger. BTeV was terminated in 2005, just after it had passed all of its reviews. Simon always regretted that this bold and innovative detector was never built.

Simon then took over the construction of the forward pixel (FPIX) detector for the CMS experiment. He soon became one of the leaders of tracking in CMS, serving on its management board. After the delivery of the FPIX, Simon continued to lead an engineering group in the Computing Division to develop detectors that would be needed as the LHC luminosity rose. He was spokesperson of test beam efforts to tackle this problem. Despite being gravely ill, Simon helped advance the CMS upgrade project to CD-1.

Just last week, Simon, though very weak, told us that he regretted not being able to continue contributing to the upgrade and exhorted us to do a great job. Typical Simon!

Simon was a physicist of uncommon achievement, creativity and vision. We will miss him greatly. A scientific tribute in his honor will be held Saturday, March 22, at 10 a.m. in CDF conference room 327. Members of his family will be in attendance.

Joel Butler (PPD), Patricia McBride (CMS) and Alan Prosser (SCD)

In the News

A big-bang theory gets a big boost: evidence that vast cosmos was created in split second

From The Washington Post, March 17, 2014

In the beginning, the universe got very big very fast, transforming itself in a fraction of an instant from something almost infinitesimally small to something imponderably vast, a cosmos so huge that no one will ever be able to see it all.

This is the premise of an idea called cosmic inflation — a powerful twist on the big-bang theory — and Monday it received a major boost from an experiment at the South Pole called BICEP2. A team of astronomers led by John Kovac of the Harvard-Smithsonian Center for Astrophysics announced that it had detected ripples from gravitational waves created in a violent inflationary event at the dawn of time.

Read more

Frontier Science Result:

Top of the world

This week saw a historic collaboration between scientists from CERN and Fermilab, as the world combination of the top quark mass was reported, using inputs from the ATLAS, CDF, CMS and DZero collaborations.

Disponible en español

The top quark has only ever been produced and detected in two places on Earth: at Fermilab, where the DZero and CDF collaborations first discovered this most massive particle in 1995, and at CERN, where the Large Hadron Collider generates so many top quarks that the ATLAS and CMS experiments are often described as top factories. Now, in an historic act of trans-Atlantic collaboration, analyzers from all four of these experiments have worked together to combine their measurements and produce the most precise determination of the top quark mass.

The act of collating and averaging measurements from different sources is very common in high-energy physics. In fact there is a dedicated organization charged with doing just this, the Particle Data Group. However, combining the various top quark mass measurements is nontrivial, because many of the procedures and inputs are shared between different experiments. This means that a naive average of the different results is no longer optimal. To illustrate this, consider a group of measurements of some object's weight, using a set of scales. If the scales under- or overestimate the weight every time, this will affect all the measurements in the same way. The uncertainty on the result caused by the calibration of the scales will remain unchanged however many measurements are performed.

This world combination, a year in the making, takes a total of 11 individual measurements from all four experiments (six from the Tevatron and five from the LHC), and performs a weighted average that properly accounts for all correlations between different parts of the analyses. All measurements use top-antitop events in one of four possible decay patterns: lepton + jets, dilepton, all jets, or missing transverse energy + jets. A significant challenge is separating the uncertainty on every measurement into standardized categories, as well as assessing their correlations both within each experiment and between the different collaborations and accelerators. Scientists test different assumptions of the correlations to ensure that the results are stable with respect to these tricky decisions.

The combination is designed to minimize the total uncertainty on the top quark mass, and it gives a final result 173.34 GeV, with a total uncertainty of just 0.76 GeV, or around 0.4 percent. This is the most precise evaluation of the top quark mass ever made and the first time that the full global combination has included a complete assessment of the correlations. Reaching such excellent precision is important, as the top quark mass plays a vital role in the Standard Model of particle physics and also has cosmological implications through the "stability" of the universe. Given that collaborations from both colliders continue to work on improved individual measurements, it looks like there is plenty more trans-Atlantic collaboration to come, which bodes well for the future precision of this and other fundamental Standard Model parameters.

Mark Williams

Measurements from the CDF and DZero experiments represent the Tevatron in the top mass combination.
The LHC top mass measurements came from both ATLAS and CMS collaborations.
In Brief

Construction to begin on receptionist desk in atrium

The Wilson Hall atrium will soon have a new receptionist area. Image: FESS

Today work begins on reconfiguring the reception area in the Wilson Hall atrium. Construction will continue for approximately one month. When the area is complete in April, the new space will be home to a laboratory receptionist and the Fermilab Cultural Events box office.

Photos of the Day

Snowy continuity

This morning's snowfall recalls last week's snowstorm. The laboratory grounds were covered in white last week. Photo: Jesus Orduna, Rice University
Last week's snow whitened exactly one side of the obelisk in front of Wilson Hall. Photo: Jesus Orduna, Rice University

FermiPoint doctor-is-in booth in atrium - today

Emergency drills in Village - March today

URA Thesis Award competition deadline - today

Walk 2 Run begins today

International folk dancing special workshop at Kuhn Barn - today

Photography contest - through March 21

Two yoga classes offered - register by March 24

Weight Management registration deadline March 27

2014 FRA Scholarship applications due April 1

LabVIEW seminars scheduled on April 10

MySQL relational database management course - April 22-23

West bike rack area closed

Portions of west atrium stair closed for construction

Indoor soccer