AD keeps records coming

The Accelerator Division achieved three new records last week and obtained some of the highest luminosity stores yet.

During approximately the last two weeks, initial luminosity has been steadily climbing from 300 µb-1/s to more than 350. With high initial luminosities and sustained integration time, the chances of discovery-generating collisions increases.

The average weekly integrated luminosity for the week ending Monday, March 8, rose to 61.84 inverse picobarns. This marks the third week in a row averaging over 60 inverse picobarns. In addition, two of this last week’s stores ranked among the top five largest ever.

While AD Run Coordinators Mary Convery and Cons Gattuso were announcing these records during the March 10 All Experimenter’s meeting, the Tevatron reached yet another new height, setting an average initial luminosity record of 354.4 µb-1/s up from the previous level of 353.2 .

This week of record-setting work is far from an outlier. The Tevatron’s overall integrated and peak luminosities are ahead of where they were at this time last fiscal year.

The Accelerator Division credits the success to a combination of hard work by all division lines, machine reliability that allows the stores to build upon one another, fine-tuning of equipment and, last week, studies using only an antiproton store. While the antiproton study requires more downtime, the run coordinators said it pays off in a luminosity boost and has become a regular part of accelerator operations.

You can view all of the recent luminosity plots here.

-- Tona Kunz

Service Desk announcements in 140 characters

If the laboratory’s e-mail and Internet servers go down, Service Desk representatives can find themselves informing Fermilab employees and users about the problem one-by-one over the phone.

Now the Service Desk has an additional method of communicating with the laboratory at large: Twitter. Twitter is a social networking site that allows users to post short messages, called tweets, which compile on a Web page listing the most recent messages first. You can see a user’s tweets whether or not you have a Twitter account.

Service Desk representatives will use the Twitter account to make announcements, to provide information about outages, to send warnings about phishing e-mails and to highlight relevant articles.

Click here to see tweets by FNALServiceDesk.

Click here to sign up for a Twitter account. Read this FAQ page to find answers to frequently asked questions about Twitter.

-- Eileen Berman, Service Desk group leader

New employees - March 1

Gabriel Dunn, PPD; Bridgett Thomson, FESS; Sergey Kazakov, TD.

Einstein passes cosmic test

From Nature News, posted Mar. 10, 2010

It's another victory for Einstein - albeit not a resounding one. General relativity has been confirmed at the largest scale yet. But the galactic tests used to put the theory through its paces cannot rule out all rival theories of gravity.

General relativity has been rigorously tested within the Solar System, where it explains the motion of planets with precision. But its reach between galaxies has been harder to verify and should not be taken for granted, says cosmologist Alexie Leauthaud, at the Lawrence Berkeley National Laboratory in California. "It's actually a tremendous extrapolation to assume that general relativity works on cosmic scales," she says.

If general relativity does break down at large scales, it could help cosmologists to explain away one of their biggest headaches: dark energy. In the 1990s, astronomers were surprised to discover that the expansion of the Universe is accelerating. That runs counter to the predictions of general relativity, which suggests that gravity's grip should be slowing the expansion. To explain this, cosmologists now invoke a 'dark energy', a force that makes up almost three-quarters of the matter and energy in the Universe and pushes it apart. But the origin of dark energy remains a mystery.

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