Thursday, June 19, 2014

Thursday, June 19

2:30 p.m.
Theoretical Physics Seminar - Curia II
Speaker: Liam Keegan, CERN
Title: Large N Twisted Volume Reduction of QCD on the Lattice

3:30 p.m.

Friday, June 20

11:15 a.m.
All-hands meeting - Auditorium

3:30 p.m.

4 p.m.
Joint Experimental-Theoretical Physics Seminar - One West
Speaker: Silvia Pascoli, Durham University
Title: Neutrinos: Towards an Understanding of the Origin of Neutrino Masses and Mixing Beyond the Standard Model

7 p.m.
Fermilab Lecture Series - Auditorium
Particle Fever
Tickets: $7

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Wilson Hall Cafe

Thursday, June 19

- Breakfast: Canadian bacon, egg and cheese Texas toast
- Breakfast: Greek omelet
- Ranch house steak sandwich
- Asian beef and vegetables
- Coq au vin
- Rustic club flatbread sandwich
- Peruvian beef and potato stir fry
- Shrimp gazpacho
- Chef's choice soup
- Assorted pizza by the slice

Wilson Hall Cafe menu

Chez Leon

Friday, June 20
5:30 p.m.
- Haricots verts and grape tomato salad with creme fraiche dressing
- Lobster tails with champagne butter sauce
- Spaghetti squash with scallions
- Sauteed sugar snap peas
- Mixed berry pie

Wednesday, June 25
- Rotini, summer squash and prosciutto salad with rosemary dressing
- Fresh blueberry and vanilla yogurt parfait

Chez Leon menu
Call x3524 to make your reservation.


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From symmetry

The supersymmetric bet

Particle physicists playfully take sides over whether the Large Hadron Collider is likely to discover evidence of supersymmetry. Image courtesy of Poul Damgaard, Niels Bohr Institute

Scientists at the Large Hadron Collider have exactly two years to find evidence of new particles. Cognac is on the line.

In July 2000, physicists at the Triangle-2000 meeting in Copenhagen — so called because it once rotated between three cities in Europe — passed a document around the conference room inviting attendees to predict whether, in the next 10 years, experiments at the LHC would discover evidence of a theory called supersymmetry. The losers would owe the winners bottles of liquor.

"We were enjoying ourselves," says Nobel Laureate Gerard 't Hooft of Utrecht University in the Netherlands, who signed in the "no" column of the bet. "We were so happy that the machine was about to be built which would tell us who is right. That's always something nice to see in our field."

Supersymmetry, also called SUSY, is a theory that each known fundamental building block of the universe is balanced by a partner particle of an opposing type.

"Supersymmetry is a deep idea that has played a major role in theoretical physics for the past 40 years," said physicist Nima Arkani-Hamed of the Institute for Advanced Study in New Jersey, who signed his name in the "yes" column, at a recent conference.

The theory is widely acknowledged as a mathematically beautiful answer to questions left lingering by the Standard Model of particle physics, such as why gravity is so weak and what kinds of particles make up dark matter, and it is an essential component of many models of string theory.

Read more

Kathryn Jepsen

Photo of the Day

Tucked away inside its shell

In these pages we've seen photos of a spiny softshell turtle and a snapping turtle. Now we feature this close-up of a painted turtle near the woods between Wilson Hall and Lederman Science Center. Photo: Sarah Fraser
In Brief

Illinois Teacher of the Year Pam Reilly visits Fermilab

Pam Reilly

Pam Reilly, Teacher of the Year for the state of Illinois, visited Fermilab on Tuesday. Reilly is a 2nd-grade teacher at Woodbury Elementary School in the Sandwich School District.

As Teacher of the Year, Reilly will represent almost 200,000 Illinois teachers at the International Parade of States in July at NASA's space camp in Huntsville, Alabama. The parade will feature 100 teachers: 50 from the United States and 50 from countries around the world.

Teachers will briefly share a bit about his or her home state with the other parade participants. When Reilly posted on her Facebook page a call for suggestions on topics for her talk, one commenter suggested she visit Illinois' own Fermilab, America's only dedicated particle physics laboratory.

In Brief

Performance reviews due July

It is again the time of year to reflect on our past year's performance as employees. The following parts of the performance review process must be completed in July:

  • 2013-2014 accomplishment report, to be completed by employee by July 15
  • 2013-2014 performance review form, to be completed by manager in July or August
  • 2014 salary review, to be completed in FermiWorks by manager in August. More details will follow.
  • 2014-2015 goal setting, to be completed in FermiWorks by employee and manager in fall 2015. More details will follow.

Contact Workforce Relations Manager Juanita Frazier or your D/S/C human relations partner with any questions on the review process.

In the News

Dark matter mystery deepens

From Discovery News, June 17, 2014

New results from the particle detector attached outside the International Space Station show something else beside ordinary matter is generating cosmic rays, the lead researcher said Tuesday.

More cosmic ray detections are needed before scientists will know for sure if they're seeing telltale fingerprints of dark matter colliding or if they've found particles generated by highly magnetized, rotating neutron stars known as pulsars.

"We know something new has happened, but we still do not know the origin," Massachusetts Institute of Technology physicist Sam Ting, lead researcher of the 600-member Alpha Magnetic Spectrometer science team, said at a space station research conference in Chicago.

"In a short time, we'll really be able to resolve the mystery," he said.

Read more

Frontier Science Result: DZero

Shedding light on forward muons

The forward muon scintillation counters formed a crucial part of the DZero detector in the Tevatron Run II era (2001-2011). Their characteristic overlapping plates earned them the "fish scales" nickname. Their operation and performance are described in detail in a recent publication.

Disponible en español

The DZero experiment, like all such general-purpose particle detectors, is built from a number of distinct subsystems, each designed to perform a specific task. One such component is the muon system, which forms the outermost layer of the detector. Its job is to identify muons from proton-antiproton collisions and measure their trajectories and timing information for use in both the trigger and the subsequent event reconstruction.

In fact, the muon system is itself divided into two complementary parts: three muon tracking layers and three interleaved layers of muon scintillators. The tracking layers provide precise information about the location of muons as they leave the detector, which is used to build the trajectories. The scintillators measure the times that the muons pass through, with excellent precision of less than 1 nanosecond. Together, this is all the information necessary to fully reconstruct muons in the event. A recent limited-authorship publication describes the performance of the muon scintillator counters in the forward region, demonstrating both the excellent performance and the methods used to monitor the system.

Each layer of forward muon scintillator counters forms an overlapping ("fish-scaled") set of aluminum-covered plastic plates, which produce a burst of visible light photons when a muon passes through. This light is then fed into photon counters and converted to an electric current. Because the detection medium is light-based, the information is available very soon after the initial proton-antiproton collision and is hence used to make a decision about whether or not to save (trigger) the event for later use. Triggering is essential to select the roughly 100 events per second that can be saved to tape, out of the several million proton-antiproton collisions in this time.

The timing information is also essential for identifying muons from cosmic-ray sources, which must be removed from the data sample. If a cosmic muon passes directly through the detector, it can look much like a pair of muons originating from the center. However, it will hit the top of the detector around 30 nanoseconds before the bottom, while a genuine muon pair produced in the collision will arrive at the muon system concurrently. By using appropriate timing windows, cosmic-ray muons can be almost completely eliminated from the data without significant reduction of signal efficiency.

Scientists measured the performance of the forward muon scintillators regularly using a variety of independent methods. The efficiency of the light collection components was tested on a daily basis using built-in LED sources. The scintillating plastic plates were tested with radioactive beta ray (electron) sources. The overall performance of the full system was also tested using reconstructed muons identified by the muon tracking system. All methods show consistent results: a very slow reduction in the signal sizes over time, expected due to the effects of radiation aging. This slow change was anticipated during the detector design and had no effect on the muon identification efficiency.

Overall, the detector performed very well during its entire life, with typically over 99.9 percent of counters working during data collection, and its excellent design provided extended spatial coverage and outstanding trigger capabilities.

Mark Williams

These DZero members all made significant contributions to this publication.
This week sees a transition in the DZero Frontier Science column authorship. Mark Williams is leaving, after 10 months as author, to start a CERN fellowship. He will be replaced by Leo Bellantoni, the head of the Fermilab group at DZero. We thank Mark for his excellent work over the past year.

Today's New Announcements

What's new in SharePoint 2013 seminar - today

Zumba Fitness - register today

International folk dancing in Ramsey today

Planning to attend DASTOW on June 20?

Butts and Guts class - register by June 20

Fermilab Lecture Series presents Particle Fever with Q&A - June 20

Study of Genesis through Ancient Eyes begins June 24

Sitewide domestic hydrant flushing - June 28-29

New updates available for Mac computers

FermiWorks training for managers

Registering your personal device to access the Fermilab network

Yoga classes on Mondays or Thursdays

Scottish country dancing meets Tuesdays in Ramsey Auditorium

Outdoor soccer