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Have a safe day!
Thursday, Dec. 15
2:30 p.m.
Theoretical Physics Seminar - Curia II
Speaker: Patrick Huber, Virginia Tech
Title: Predictions of Reactor Antineutrino Fluxes
3:30 p.m.
DIRECTOR'S COFFEE BREAK - 2nd Flr X-Over
THERE WILL BE NO ACCELERATOR PHYSICS AND TECHNOLOGY
SEMINAR TODAY
Friday, Dec. 16
2:30 p.m.
Joint Experimental-Theoretical Physics Seminar - One West
Speaker: Andrey Korytov, University of Florida
Title: Higgs Searches at CMS
3:30 p.m.
DIRECTOR'S COFFEE BREAK - 2nd Flr X-Over
Click here for NALCAL,
a weekly calendar with links to additional information.
Upcoming conferences |
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Thursday, Dec. 15
- Breakfast: Apple sticks
- Southwestern chicken tortilla
- Philly-style cheese steak
- Garlic herb roasted pork*
- Smart cuisine: Mardi Gras jambalaya
- Southwestern turkey wrap*
- Assorted sliced pizza
- Marinated grilled chicken Caesar salads
*carb-restricted alternative
Wilson Hall Cafe Menu
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Friday, Dec. 16
Dinner
Closed
Wednesday, Dec. 21
Lunch
- Salmon wellington
- Parmesan orzo
- Lemon pound cake w/ blueberry sauce
Chez Leon Menu
Call x3524 to make your reservation. |
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Fermilab email outage fixed
Fermilab experienced a network outage that caused some emails to be returned to the sender from 3 to 7:40 p.m. on Wednesday, Dec. 14. The problem was fixed, but if you are still experiencing email issues or have further questions, please contact the service desk.
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Fermilab potluck - Dec. 16
The third annual international potluck party will take place from 5 to 8:30 p.m. on Friday, Dec. 16, in the Wilson Hall atrium, auditorium and Art Gallery. Fermilab employees, users, contractors, funding agency employees, friends and family are all welcome to attend.
Please bring a hearty appetizer, main dish or side dish to share, along with serving utensils. Please bring enough food for 20 or more servings. The laboratory will provide non-alcoholic beverages, plates, cutlery and cups. For more information, please visit the potluck website.
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First physics experiments soon to move into former Homestake mine
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Rick Labahn, project engineer (left) and Ben Sayler, director of education and outreach at Sanford Lab, check out the almost-finished Davis Cavern, one of the two large underground caverns constructed in the former Homestake mine. Photo: Matt Kapust, Sanford Underground Laboratory
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Construction of a 12,000-square-foot research campus a mile underground is nearing completion in the Black Hills of South Dakota, and scientists will begin to move the first physics experiments underground this spring.
“We’re on schedule for occupancy in March 2012, but it’s quite a little process,” said Project Engineer Rick Labahn, understating the complexity of his job.
Labahn is directing the outfitting of the Davis Campus, which comprises two large underground halls at the 4,850-foot level of the Sanford Underground Laboratory in the former Homestake gold mine. Early next spring researchers will begin installing two experiments there—both of them at the leading edge of 21st-century physics. The Large Underground Xenon experiment, which already is taking test run data in a building on the surface, aims to become the world’s most sensitive detector to look for a mysterious substance called dark matter. Thought to comprise 80 percent of all the matter in the universe, dark matter remains undetected so far.
Read more
—Bill Harlan, Sanford Underground Laboratory
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New employees - Dec. 12
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From left: Christopher Metcalfe, TD; James Mitchell, CD; and Michael Gardner, LBNE. Photo: Cindy Arnold
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Data hints at elusive particle, but the wait continues
From The New York Times,
Dec. 14, 2011
Physicists will have to keep holding their breath a while longer.
Two teams of scientists sifting debris from high-energy proton collisions in the Large Hadron Collider at CERN, the European Organization for Nuclear Research outside Geneva, said Tuesday that they had recorded tantalizing hints — but only hints — of a long-sought subatomic particle known as the Higgs boson, whose existence is a key to explaining why there is mass in the universe. By next summer, they said, they will have enough data to say finally whether the elusive particle really exists.
If it does, its mass must lie within the range of 115 billion to 127 billion electron volts, according to the new measurements.
Read more
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A new way to find the top
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| Here is a function of the jet energy scale versus the top quark mass fitted as a two-dimensional likelihood to the data.
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As we learned on Dec. 13, finding the Higgs boson is proving to be more of a challenge every day. CDF scientists are using the top quark to try to pin down the preferred mass of the Higgs indirectly. In the Standard Model, the mass of the top quark, W boson and Higgs boson are all inter-related. If you know any two of the three exactly, you can predict the mass of the third. That’s one of the motivations for scientists to measure the top quark mass with high precision—to get further insight into the mass of the long-hypothesized, but still undetected, Higgs boson.
Since the discovery of the top quark at the Tevatron by CDF and DZero in 1995, scientists have made dozens of top quark mass measurements using various decay modes of the top and anti-top quark pair. Recently, CDF physicists made a measurement of the top quark mass with an entirely new set of data. This measurement will add unique information into the overall picture of the top quark mass and improve the precision of its mass measurement.
Scientists collected a data set consisting of events with a specific signature. These types of events occur when a top or antitop quark decays into a tau lepton or when an electron or muon from the same type of decay is not observed.
The measurement under discussion is performed using a template method. Physicists first build several physical observables with samples whose top quark masses are already known. The shape of those samples is compared to the same observables built using the collected data set. Scientists extract a most-likely top quark mass for the data by deciding which known sample the unknown sample looks the most like.
Using approximately 60 percent of the overall dataset collected at CDF, physicists identified 1,432 candidate events that can be used to measure the top mass. With this unique data sample, CDF physicists measured the top quark mass to be 173.2 ± 2.6 GeV/c2. The measurement is in excellent agreement with the other CDF measurements. This result will soon be incorporated into overall CDF top quark mass combination, helping scientists locate where the Higgs might be hiding.
Learn more
—Edited by Andy Beretvas
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These CDF physicist contributed to this data analysis.
From left: Hyun Su Lee and Jian Tang, both from the University of Chicago; Fermilab Deputy Director Young-Kee Kim and Gabriele
Compostella, INFN-CNAF.
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Breezy
