 | Thursday, October 13, 2005 |
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Thursday, October 13
Friday, October 14 |
 Chance of Rain 68º/51º
Extended Forecast |
Secon Level 3 |
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Thursday, October 13 -Santa Fe Black Bean Soup -Sloppy Joe -Stuffed Peppers -Sauteed Liver & Onions -Baked Ham & Swiss on a Ciabatta Roll -California Pizza -Crispy Fried Chicken Ranch Salad The Wilson Hall Cafe accepts Visa, Master Card, Discover and American Express at Cash Register #1. |
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Thursday, October 13 Dinner - Shrimp Bisque -Quail w/Garlic Rosemary Sauce -Mashed Roots -Green Beans w/Bacon & Balsamic Vinegar -Chocolate Hazelnut Souffle
Wednesday, October 19
Chez Leon Menu |
| Fermilab Today is online at: http://www.fnal.gov/today/ Send comments and suggestions to today@fnal.gov Fermilab Today archive Hurricane Relief Page Fermilab Today PDF Version Fermilab Result of the Week archive Fermilab Safety Tip of the Week archive Linear Collider News archive Fermilab Today classifieds Subscribe/Unsubscribe to |
| Oct. 13 Marks 20 Years Since Tevatron's First Collision
CDF will commemorate the anniversary during a special session of the CDF collaboration meeting on October 27, from 1:30 to 3:00 p.m. in One West. |
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Twenty years ago today, the CDF collaboration observed the first collisions between protons and antiprotons produced at the Tevatron. It was the dawn of the collider physics era at Fermilab; but it didn't come easy. "I remember we were scrambling to get the vertex detector together," said Fermilab physicist Bob Kephart, who worked at CDF during that time. "Even as the detector rolled into the ring [at the speed of a few feet per hour], some of us were still working on it." Long before this point, there were myriad challenges for the Accelerator Division. First there was the time-consuming process of making and storing enough antiprotons to run. Once that was done, batches of protons had to be injected, coalesced and accelerated to 150 GeV in the Main Ring before blasting into the Tevatron where they could be accelerated to an even greater energy of 800 GeV. Then, after those protons were orbiting correctly, the stored antiprotons had to undergo the same process before being transferred to the Tevatron to circle in the opposite direction. The timing had to be perfect: If the antiprotons were moved from the Main Ring to the Tevatron at the wrong moment, their entry might interfere with the protons already inside. The fact that the particles were nearly impossible to see made the whole thing even more difficult. "All along the way, things could go wrong," said Alvin Tollestrup, who was the CDF spokesman at the time. "And if they did, the scientists had to guess what the problem was and start all over again."
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Trust on Grid Goes Global
Grids harness the power of geographically dispersed computing resources, experimental facilities and research centers. There are now many independently operated grids across the globe, and users able to work on one can't necessarily gain access to another. Making sure that owners of different grids trust each other's security procedures is essential to letting researchers access all available resources.
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From PhysOrg.com, October 11, 2005: Can an Electron be in Two Places at the Same Time? Max Planck Researchers in Berlin show that for electrons from nitrogen molecules, the wave-particle character exists simultaneously. In something akin to a double-slit experiment, scientists at the Fritz Haber Institute of the Max Planck Society, in co-operation with researchers from the California Institute of Technology in Pasadena, California, have shown for the first time that electrons have characteristics of both waves and particles at the same time and in virtually the push of a button can be switched back and forth between these states. The researchers provided evidence that disrupting the reflective symmetry of these molecules by introducing two different heavy isotopes, in this case N14 and N15, leads to a partial loss of coherence. The electrons partially begin to localise on one of the two, now distinguishable, atoms. The results could have implications for the building and control of "artificial molecules", which are made of semiconductor quantum dots, and are a possible component of quantum computers. (Nature, September 29, 2005).
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| DZero Measures Life of Orbitally Excited Mesons | ||
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Mesons are bound states of a quark and an anti-quark. In contrast to their relatives, baryons, which consist of three quarks and are sometimes stable (like protons, for example), mesons are not part of our everyday life. However, similar to the hydrogen atom in atomic physics, mesons are simple systems that can be used as a testing ground for theoretical predictions. If one of the two constituent quarks in the meson is heavy then the equations of the theory are simple enough to be solved. As a result, there have been clear theoretical predictions about properties of heavy mesons that have either "beauty" (B mesons) or "charm" (D mesons) quarks inside. Physicists at Fermilab have a long history of studying heavy B and D mesons at the Tevatron collider. These mesons are abundantly produced in the proton-antiproton collisions, and experiments use complicated trigger algorithms and electronics to select these events from billions of other collisions. At the analysis phase, B mesons are reconstructed combining a muon and several other charged particles. Experimentalists like muons because they do not interact much with matter: they reach the outermost part of a detector, traversing thick slabs of iron, and this allows us to easily recognize them. The other particles in the same event must include at least one excited D meson. What are the excited mesons? Again, similar to the hydrogen atom, the quarks inside the D meson can have relative orbital momentum, and exist in an "excited" state. Following the same analogy, the "excitement" is removed by a decay to a state with lower potential energy (or in this case to a state with lower mass), emitting an extra particle. As always in quantum mechanics, the orbital momentum is quantized and also obeys selection rules, which allow only certain decays. With the DZero experiment, we detected hundreds of B meson transitions to the excited D meson states, which is much higher than was previously seen in other experiments. For the first time we have measured an important parameter predicted by theory: the ratio of probabilities to decay to one of two possible narrow states. This new DZero result will be published in Physical Review Letters. |
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| Result of the Week Archive |
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October 10 - 12 - During this 48 hour period, two stores provided 15 hours and 40 minutes of luminosity. - CDF solenoid dumped helium. - Pelletron down - Booster LCW repaired, then had ORBMP vacuum problem.
Read the Current Accelerator Update
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Yoga Classes start October 25
Classes are held on Tuesdays from 12:00 p.m. to 1:00 p.m. in the Auditorium at Wilson Hall. The eight-week session will begin October 25 and run through December 13. The cost for this session is $80.00. Registration can be done by mail, fax x5207, in person in the Recreation Office or if you are using a credit card for payment, by phone. These classes DO NOT require a recreation membership. More Information Women's Organization Luncheon
Volunteer for Girl Scout Projects
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