Fermilab TodayThursday, March 25, 2004  
Thursday, March 25
2:30 p.m. Theoretical Physics Seminar - Curia II
Speaker: H. Collins, Carnegie Mellon University
Title: The Fate of the Alpha-Vacuum
3:30 p.m. DIRECTOR'S COFFEE BREAK - 2nd Flr X-Over

Friday, March 26
3:30 p.m. DIRECTOR'S COFFEE BREAK - 2nd Flr X-Over
4:00 p.m. Joint Experimental Theoretical Physics Seminar - 1 West
Speaker: A. Nomerotski, Fermilab
Title: Recent Dzero Results on B, QCD, and New Phenomena

Thursday, March 25
Wild Mushroom soup
Baked ziti w/meatballs and garlic bread $3.50
Sesame chicken over steamed jasmine rice $3.50
Buffalo chicken w/blue cheese wrap $4.75
Grilled brat w/peppers and onions $4.75
Hand rolled Hanabi sushi $4.75

Eurest Dining Center Weekly Menu
Chez Leon
WeatherThunderstorms Likely 66º/55º

Extended Forecast

Weather at Fermilab


Secon Level 3

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Annual DOE Program Review Posters on Display in Wilson Hall
DOE Annual Review Poster Session
Tug Arkan makes some last minute adjustments to his poster, "X-Band RF Structure Fabrication for Linear Collider R&D." (Click on image for larger view.)
As part of Fermilab's presentations to the Annual DOE Program Review this week, researchers have prepared thirty-three posters covering a broad range of topics, from accelerator and computing projects to physics research results. Given the breadth of the Fermilab program and the time limits of a two-and-a-half day review, many of the posters present topics that were only briefly covered in oral presentations to the review committee or not at all.

"These reviews are crucial to Fermilab's future, and the poster displays play a large part in their success," said Winslow Baker, a member of PPD who helped organize the poster session. "They are an excellent opportunity for young people to receive recognition and to meet other physicists active in our field."

The posters are on display on the 15th Floor North cross-over of Wilson Hall. They will remain available for viewing through the weekend, and everyone is invited to drop by and have a look. While the posters are not a complete summary of the Fermilab program by themselves, they do provide a glimpse of the diversity of Fermilab's efforts.

So Long, Pamela Mathis
Pam Mathis
Pamela Mathis
Pamela Mathis will retire today in her 25th year at Fermilab. After 21 years in the stockroom in Wilson Hall, she spent the last three in the Business Services Section's Property Management group, tracking and storing thousands of old computers and other items from around the lab.

"Her knowledge will be missed," Jack Kelly, manager of the Property and Inventory Control Department, said. Getting to know your way around a warehouse with over 4800 different line items takes time.

Working at the railhead--surveying, sorting, and moving large pieces of steel or spools of cable for future projects--Mathis has become familiar with Big George, the 70,000-pound forklift. But she will probably miss her human colleagues the most. She liked knowing "you could get the job done no matter what…they knew what they were doing."

Mathis was born in Iowa, and grew up in southern California before coming to Illinois. She now lives in Montgomery and plans to move to Phoenix with her husband, where she will have more time to soak up the sun and go fishing.

Accelerator Update
March 22 - March 24
- On Tuesday technicians completed work on TeV sector A4 and cooldown began
- A magnet located in TeV sector F0 (HV100) required repair
- Operations successfully hipotted the TeV Wednesday morning

View the current accelerator update
View the Tevatron Luminosity Charts

In the News
From the Chicago Tribune, March 24, 2004
Fermilab reaches out to neighbors
Workshop to focus on public support
by William Grady
A meeting this weekend with neighbors might be as important to the future of Fermi National Accelerator Laboratory as the improvements in recent years to exotic equipment that sends millions of subatomic particles whizzing through its tunnels.

The all-day workshop, scheduled for Saturday, will be the first meeting for members of Fermi's new community task force on public participation--an effort by the nation's largest high-energy physics lab to strengthen ties with neighbors in DuPage, Kane and DeKalb Counties.
read more

Fermilab Result of the Week
CDF Finds Top with Bottom
CDF Result of the Week
The number of jets in b-tagged events containing a W boson. The observed excess over the background predictions for events with 3 or more jets is consistent with a top quark production cross section of 5.6 +- 1.1 (stat.) +- 0.8 (syst.) pb.(Click on image for larger version.)
Top quarks are produced in about one out of every ten billion collisions at CDF and DZero. Measuring exactly how often they are produced at Tevatron energy (1.96 TeV) is one of the first questions about top quarks we have tackled in Run II. Each top quark decays into a W boson and a bottom quark. The W boson can then decay into either leptons or quarks. Quarks are observed as jets of particles in the detector. We look for events in the CDF detector containing a high-momentum charged lepton, missing energy from a neutrino, and three or more jets.
CDF Group
Postdocs Takasumi Maruyama (U. Chicago) and Jason Nielsen (LBNL), and graduate students Heather Ray (U. Michigan) and Henri Bachacou (LBNL) worked on the CDF trigger system and silicon detectors in addition to hunting top quarks. (Click on photo for larger version.)
The hard part is separating out the top quark events from the "background" events which come predominantly from production of W bosons along with jets. The tracking precision of the CDF silicon detector makes it possible to identify the characteristic displaced vertices from b quark decays. By employing a "b-tagging" technique similar to one used to discover the top in Run I, we can keep half of the top quark events while removing 95% of the background events.

Stephen Miller
Stephen Miller is a
postdoc at Michigan
who helped build the
CDF Level 2 trigger
before measuring top
The final step is estimating the number of remaining background events in the b-tagged sample. One technique makes a careful accounting of all possible background events using a combination of estimates from data and Monte Carlo. This line of attack was pursued by Henri Bachacou, Jason Nielsen, and Weiming Yao from LBNL, and by Heather Ray, Stephen Miller, Dan Amidei and Tom Wright from the University of Michigan. A new approach, developed by Takasumi Maruyama and Mel Shochet at the University of Chicago, measures the fraction of top events in the sample by fitting the energy spectrum of the leading jet in the event, which tends to be higher for top events than for background events. This method determines the background spectrum almost entirely from data. The two complementary methods give consistent results for the top production cross section and are currently the world's most precise single measurements.

CDF Result of the Week
Fit (black curve) to the transverse energy spectrum of the leading jet in the same b-tagged events. This two-component fit, uses the shape of top signal (red) and that of background (blue), and indicates that 67% of the selected events are from top, giving a production cross section of 6.0 +- 1.5 (stat.) +- 1.0 (syst.) pb. (Click on image for larger version.)

Result of the Week Archive

New Book Purchase Suggestion Lists
New book purchase suggestion lists for the week of March 23 are now available online. These include Majors book lists in four subject areas. There is also an Amazon suggestion list in the form of a shopping cart, viewable by entering the password "library."

Spring Fling Book Fair - April 21 & 22
Fermilab's Recreation Office will sponsor its "Spring Fling" Book Fair, hosted by Books are Fun, in the Atrium on Wednesday, April 21 from 10:00 a.m. until 6:00 p.m. and on Thursday, April 22 from 7:00 a.m. until 3:00 p.m.

Coed Softball League
Softball season is almost here. Games start on 5/5/2004 and take place in the village on Wednesdays or Thursdays starting at 5:15 pm. Captains meeting in the cafeteria at noon on 4/14/2004. Contact Dave Hockin if you're interested in playing. Entire teams or individuals, all are welcome.

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