Thursday, Aug. 25, 2011

Have a safe day!

Thursday, Aug. 25
11 a.m.
Joint Experimental-Theoretical Physics Seminar - One West
Speaker: Alex Sousa, Harvard University
Title: New Results from MINOS
2 p.m.
Computing Techniques Seminar - FCC1
Speaker: Rajkumar Kettimuthu, Argonne National Lab/University of Chicago
Title: Data Movement Challenges in the Era of 100 Gbit and Terabit Networks
2:30 p.m.
Theoretical Physics Seminar - Curia II
Speaker: Chris Bouchard, University of Illinois, Urbana-Champaign
Title: The Brown Muck of B Mixing: Beyond the SM
3:30 p.m.

Friday, Aug. 26
3:30 p.m.
4 p.m.
Joint Experimental-Theoretical Physics Seminar - One West
Speaker: Avi Yagil, University of California, San Diego
Title: Searches for the Higgs Boson at CMS

Click here for NALCAL,
a weekly calendar with links to additional information.

Upcoming conferences


Take Five

Weather Sunny

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Secon Level 3

Wilson Hall Cafe

Thursday, Aug. 25

- 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 salad*
*Carb-restricted alternative

Wilson Hall Cafe Menu

Chez Leon

Friday, Aug. 26

Wednesday, Aug. 31
- Pork satay w/ peanut sauce
- Jasmine rice
- Pea pods
- Coconut cake

Chez Leon Menu
Call x3524 to make your reservation.


Fermilab Today

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CMS Result of the Month

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Tevatron shows that being sensitive is a good thing

CDF (red) and DZero (yellow) recorded the East Coast earthquake. Image courtesy of Todd Johnson, AD
CDF (red) and DZero (yellow) recorded the Colorado earthquake. Image courtesy of Todd Johnson, AD

On Tuesday, Aug. 23, the Tevatron accelerator knew something none of the people operating it knew. It felt what employees didn’t, and it reported the news faster than the media could upload it to the Internet.

A 5.9-magnitude earthquake had struck the East Coast, and the super-sensitive Tevatron felt it as it happened about 600 miles away. It had also registered a similar quake in Colorado the night before.

The quakes were recorded by sensors on large underground focusing magnets that compress particle beams from the four-mile Tevatron ring into precision collisions at the CDF and DZero detectors. The sensors keep these areas most sensitive to misalignment under constant surveillance. Quakes can jiggle small numbers of particles – less than one percent of the beam – out of alignment and force the shutdown of parts of the three-story detectors to avoid damage. Tevatron operators compare the sensor recordings with updates from the U.S. Geological Survey to rule out natural causes before having to spend time diagnosing machine trouble that caused beam movement.

Typically, two quakes occurring in this short a timeframe would cause headaches for those who run the Tevatron, but fortunately the machine didn’t have beam in the tunnels at the time.

The Tevatron has recorded more than 20 earthquakes from all over the globe, as well as the deadly tsunamis in Sumatra in 2005 and in Japan in March.

Tona Kunz

Special Announcement

East parking lot work

On Friday, Aug. 26, asphalt work will begin in Wilson Hall’s east parking lot. Workers will patch and seal, then stripe the asphalt, and the work will continue through Sunday, Aug. 28. There will be access to the loading dock, but there will be limited parking on Friday and no parking on Saturday and Sunday. Drivers can expect modified traffic patterns in the east lot on Friday and around the auditorium on Saturday and Sunday. Weather conditions could affect this schedule.

Photo of the Day

New employees - Aug. 8

Andrei Gaponenko, PPD, and David Reed, BSS. Photo: Cindy Arnold

In the News

Giant camera will look back seven billion years

From NBC Phildelphia, Aug. 23, 2011

Will try to unravel mystery of dark energy

A massive, 570-pixel camera that can peer back seven billion years ago is on its way to Chile where it will be used to study to study a mysterious force in the universe known as dark energy.

The camera, which has multiple lenses including one three feet in diameter, is being shipped from Illinois to the Cerro Tololo Inter-American Observatory where it will survey faint galaxies in the distant universe.

Dark energy, only discovered in 1998, is present throughout the universe. Scientists know little about it except that it seems to be speeding the expansion of the universe.

"There's enough data that people know what we don't understand, but there's not enough data to explain it yet," Brenna Flaugher told NPR.

Read more

In the News

More inverse femotobarns, fewer places for the Higgs to hide

From ars technica, Aug. 23, 2011

A month ago, a physics meeting that took place in France provided some of the first results in the LHC's hunt for the Higgs boson, a particle that is theorized to provide mass. Based on theory, we don't know what mass the Higgs might be, but we do know what it might decay into, so researchers have been looking for signs of these decays across a broad range of masses. Now, India is hosting the Lepton Photon meeting, and the talk is again about this boson. And, for the moment, we're not much closer to knowing whether it exists.

The search for the Higgs involves modeling what sort of particles known processes generate at specific energies (because e = mc2, these energies correspond to masses). We can then compare that to what is actually seen in the detectors. If the detectors see the predicted number of the particles at a given mass/energy, we can exclude that.

Read more

Result of the Week

Higgs, SUSY and taus, oh my!

The DZero Result of the Week describes rather complex measurements. The accessible language can sometimes mask the true difficulties scientists face in searching for answers.

Making a physics measurement is hard—even for an analysis that doesn’t confirm a theory. Scientists are searching for evidence that would support two popular theories—supersymmetry and Higgs bosons. Today’s article mixes the two. Like all measurements, this is a challenging endeavor.

The first step is to figure out ways to select the right collisions to record. After all, we only write 0.01 percent of the collisions to tape. Assuming that we selected the correct collisions and the detector is functioning properly, finding events with a supersymmetric Higgs boson is extremely challenging. From the billions of recorded events, only a handful might have the desired characteristics. And to even try to identify the desired events requires tremendous care and the assimilation of a lot of information.

For instance, the simplest extension of the Standard Model that includes supersymmetry suggests that perhaps Higgs bosons might frequently decay into tau leptons. Tau leptons are the heaviest cousin of the familiar electron. However, tau leptons are unstable and can decay into muons (another electron cousin), electrons or even charged pions.

To identify tau leptons, we combine information from tracking and energy-measuring detectors and occasionally the muon detection system. While identifying the events that contain tau leptons is difficult, DZero scientists can do that. They have then exploited this capability to search for events in which the tau lepton came from supersymmetric Higgs bosons.

DZero scientists also made an additional measurement, searching for supersymmetric Higgs bosons that are made simultaneously with a bottom quark. Finding bottom quarks poses its own interesting technical challenges, as we must identify where it decayed, just millimeters after it was created.

These searches did not confirm the Higgs bosons in the simplest supersymmetric model, but they did provide valuable constraints on the theory. Despite not finding exactly what we were looking for, our ability to narrow the field is an invaluable contribution. Knowing what something isn’t is an important part of finding out what it is.

Don Lincoln

These physicists performed these analyses.
An analysis as tricky as this requires clever algorithms to select the interesting events from the deluge of data seen by the detector. These physicists are responsible for the operation of the trigger that connects DZero tracking detectors with the energy measuring ones.
Accelerator Update

Aug. 22-24

- One store provided ~8.5 hours of luminosity
- Tevatron Transfer Hall vacuum leak repaired
- Tevatron personnel conducted 3x3 studies
- Antiproton source target air blower repaired

Read the Current Accelerator Update
Read the Early Bird Report
View the Tevatron Luminosity Charts


Latest Announcements

Athletic leagues: Outdoor soccer - Tuesdays and Thursdays

English country dancing - Aug. 28

Fermilab photography club

Wilson Hall east lot asphalt work - Aug. 26 - 28

"Is the Bible Reliable?" lunchtime video series - begins Sept. 6

Creative writing group - today in WH4SE Abacus

FermiMail brown bags - Aug. 26

Blackthorn: Traditional Celtic band - Aug. 27

What’s new in Mathematica 8? - Aug. 31

An introduction to Mathematica for engineers - Aug. 31

Bohr and Heisenberg at Elgin Arts Theatre - Sept. 16 - 25

Yoga - through Oct. 25

All blood types needed, especially B-, AB-, O- and B+, please help if you can

Nordic walking at Fermilab

Bowlers wanted for 2011/2012 bowling season

Join Fermilab's new scuba diving club

Open badminton

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