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
THERE WILL BE NO ACCELERATOR PHYSICS AND TECHNOLOGY
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
Annual DOE Program Review Posters on Display in Wilson Hall|
|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|
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.
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.
CDF Finds Top with Bottom|
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.
|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
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.
Stephen Miller is a|
postdoc at Michigan
who helped build the
CDF Level 2 trigger
before measuring top
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.