Thursday, Sept. 5, 2013

Have a safe day!

Thursday, Sept. 5

2:30 p.m.
Theoretical Physics Seminar - Curia II
Speaker: Andrea Peterson, University of Wisconsin - Madison
Title: W' Decays to Heavy Higgs Particles

3:30 p.m.

Friday, Sept. 6

3:30 p.m.

4 p.m.
Joint Experimental-Theoretical Physics Seminar - One West
Speaker: Bryce Littlejohn, University of Cincinnati
Title: A Relative Spectral Measurement of Neutrino Oscillation at Daya Bay

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Thursday, Sept. 5

- Breakfast: Canadian bacon, egg and cheese Texas toast
- Breakfast: sausage gravy omelet
- Chopped-pork barbecue sandwich
- Smart cuisine: Hawaiian stir fry
- Mom's meatloaf
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- Greek chicken salad
- Green pork chili
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- Assorted pizza by the slice

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Chez Leon

Friday, Sept. 6

Wednesday, Sept. 11
- Vietnamese caramelized pork and rice noodle salad
- Pomegranate poached pear

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From symmetry

Upgraded Fermilab neutrino beam back in business

After more than a year of improvements, Fermilab's accelerator complex has begun sending neutrinos to experiments at the lab and in Minnesota. Photo: Reidar Hahn

[Wednesday], for the first time, Fermilab switched on its newly revamped neutrino beam, soon to be one of the most intense neutrino beams in the world.

Neutrinos are light, neutral particles that can zip through solid rock as if it were empty space. In order to catch enough of these particles to study them, scientists use particle accelerators to create dense beams of neutrinos and aim them at large particle detectors.

Scientists create a beam of neutrinos at Fermilab by firing protons into a target made of carbon, a process that releases other charged particles that can be steered and focused. Those particles eventually decay into lighter particles, including neutrinos. The other particles are absorbed in the earth, leaving a clean neutrino beam.

The laboratory's accelerator complex (part of which is pictured above) had been shut down for more than a year to undergo a comprehensive set of upgrades in preparation for the start of the NOvA experiment. Scientists on NOvA will study the properties of neutrinos using a 200-ton detector at Fermilab and a 14,000-ton detector in northern Minnesota.

"Almost all neutrino experiments are limited by the fact that neutrinos interact with matter so infrequently," says Harvard physicist Gary Feldman, co-leader of the NOvA experiment. "NOvA is no exception. So the accelerator physicists at Fermilab came up with a scheme to approximately double the power of their neutrino beam."

Accelerator physicists have updated some of the beamline through which the protons travel, the radio-frequency cavities that boost their energy, the kicker magnets that switch them to the desired path, the target they crash into, and one of the magnetic horns that focuses the emerging particles into a beam. They've changed the positions of the horns to make a higher energy neutrino beam. They've given the whole process an additional boost by repurposing part of the accelerator complex to speed up proton injection in the Main Injector, Fermilab's most powerful operating particle accelerator.

Physicists are restarting the accelerator complex slowly, says Ioanis Kourbanis, head of Fermilab's Main Injector department. [This week] the neutrino beam should run at about one-tenth of its eventual power level. In a couple of weeks it should be back to about its pre-upgrade level, and then it will gradually ramp up to its full potential.

The first modules of the NOvA far detector, still under construction, will start taking data immediately, but the experiment cannot fully take advantage of the new beam until both of its detectors are complete next year. However, two already operating neutrino experiments—MINOS+ and MINERvA—will benefit from the upgrades to the neutrino beam right away.

Read more

Kathryn Jepsen

Video of the Day

Big questions: missing antimatter

The imbalance between matter and antimatter in the universe is one of the big mysteries of modern physics. Both should have existed in equal amounts just after the big bang. But when we look out into the cosmos, we see only matter and no antimatter. US CMS Education and Outreach Coordinator Don Lincoln explains this conundrum, and what physicists are doing to solve it, in a new video. View the video. Video: Fermilab
In the News

Fermi scientists begin survey of night sky to learn about fundamental forces of the universe

From Chicago Sun-Times, Sept. 4, 2013

Fermilab's newest instrument, the Dark Energy Camera, offers a unique glimpse at the cosmos.

In each snapshot it takes, more than 1,000 galaxies up to 8 billion light years away are revealed.

The Dark Energy Survey, a project that seeks to understand some of the most fundamental questions of the universe by pointing one of the world's most powerful cameras skyward, has officially launched.

The 570-megapixel camera, made of five precisely shaped lenses, the largest up to a yard across, was built at Fermilab and mounted above a telescope at the National Science Foundation's Cerro Tololo Inter-American Observatory in the Andes Mountains in Chile.

Read more

Frontier Science Result: CDF

Observing a heavy bottom baryon

This shows part of the mass spectrum for the Λb*0 candidates. The projection of the corresponding unbinned likelihood fit is superimposed.

Physicists from the CDF collaboration have observed the Λb*0 baryon. This state is made of two light quarks (up and down) and a heavy (bottom) quark. It has exactly the same quark content as the ground state Λb0 baryon. The intriguing difference between the newly observed state and the well-known Λb0 is that the pair of light quarks (u, d) in Λb*0 orbits the heavy b quark with an orbital angular momentum that we denote L=1. Physicists call such states orbitally excited resonances. The newly observed state is extremely unstable, as its decay is driven by the strong force. The Λb*0 disintegrates promptly, in less than a billionth of a trillionth of a second (10-22 seconds) to a stable Λb0 and two pions. The CDF detector allows physicists to reconstruct the paths of the two prompt pions and of the ground state Λb0 particle. Unlike the case of the orbitally excited Λb*0 decay, it is the weak force that is responsible for the decay of the Λb0, which goes slowly (it takes about a billionth of a second).

From the decay particles (Λb0 and two pions), CDF physicists were able, using the full Run II data sample, to obtain a mass spectrum. The distribution is shown in the top figure. The narrow peak at approximately 21 MeV represents the orbitally excited Λb*0 resonance state with a total spin (J) of 3/2. We observe 17 ± 5 signal events. This work confirms the previous observation of the Λb*0 made by the LHCb experiment at the LHC. The mass of the Λb*0 is now determined to be 5919.22 ± 0.84 MeV/c2.

The observation of this heavy bottom baryon provides a new benchmark in the spectrum of hadron states to which predictions by theoretical models can be compared. Measurements of the masses of these states are important for our understanding of quantum chromodynamics, the fundamental theory of strongly interacting matter. Handling the enormous amount of collected data was a particularly challenging part of this analysis.

Learn more

edited by Andy Beretvas

These CDF physicists contributed to this data analysis. From left: Sally Seidel, Igor Gorelov and Prabhakar Palni, all from the University of New Mexico.
Photo of the Day

Portentous sky

Tenebrous clouds passed over Wilson Hall as a storm rolled in on Friday. Photo: John Kuharik, AD

Today's New Announcements

Nigel Lockyer meets with employees today, users tomorrow and Tuesday

Barn Dance - Sept. 8

International folk dancing meets Thursday evenings in Ramsey Auditorium

Accelerate to a Healthy Lifestyle

Annual ICW flush begins Sept. 9

Life on Mars - Fermilab Lecture Series - Sept. 13

TRAIN has two new enhancements

Access 2010 classes scheduled

MS Excel and Word classes offered this fall

Interpersonal Communication Skills class scheduled for Dec. 4

Abri Credit Union special offers

Scottish country dancing meets Tuesday evenings in Auditorium

Chicago Blackhawks preseason discounts