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In this issue:
A New Year for BaBar and PEP-II
Colloquium Monday: Bayes vs. Frequentism
Caution: Bicycles at the Main Gate

SLAC Today

Friday - January 19, 2007

A New Year for BaBar and PEP-II

Upgrades on the BaBar detector and PEP-II accelerator continued into the first week of 2007. Collaborators turned them on again this week after a four-month shutdown.

With electrons and positrons flowing, BaBar and PEP-II are celebrating a new year with a new run.

With its upgrade complete, the BaBar detector began collecting cosmic rays on Jan. 6 while waiting for beam to arrive. The newly improved PEP-II accelerator began storing beams on Jan. 15. Collisions that produce physics data will start soon.

"All the technicians, physicists and maintenance crews did a superb job installing many important upgrades in PEP-II during the last four months. We now have the pieces in place to deliver the next level of luminosity to BaBar," said John Seeman, head of the Accelerator Systems Division.

The BaBar collaboration did extensive work during the down time, especially installing a better muon identification system, to take full advantage of the enhanced luminosity, or number of events the detector will see. Read more...

Colloquium Monday

Bayes vs. Frequentism

In next week's colloquium, Professor Louis Lyons of Oxford will present "Bayes versus Frequentism: The Return of an Old Controversy." In this lecture, Lyons will discuss two very different approaches to analyzing data, using examples both from every day life and from the world of physics. Cases where the resulting answers differ significantly will also be examined in such a way that they should be accessible to those with little previous knowledge of statistics.

Louis Lyons is a member of the Oxford Physics Department. He most recently worked on the DELPHI experiment at CERN and the CDF experiment at Fermilab. He has a special interest in statistics as applied to particle physics analyses, and wrote the book "Statistics for Nuclear and Particle Physicists." More recently he initiated the PHYSTAT series of Conferences and Workshops on statistical issues in Particle Physics, Astrophysics and Cosmology, one of which was held at SLAC in 2003. He is currently visiting SLAC until the end of March, and is very happy to discuss interesting statistical issues with SLAC physicists.

The colloquium takes place Monday at 4:15 in Panofsky Auditorium. All are invited to attend.

Caution: Bicycles
at the Main Gate

(Image - Bike Lane)

The Sand Hill Road bike lane (Image courtesy of Simon Ovrahim)

"Last week as I crossed Saga Lane into the main gate, a driver coming from 280 didn't look before merging and turning right," said SLAC machinist Roland Kurz. "That was the second time in the past few months that I've almost been hit. Passing through SLAC's main gate is the worst part of my commute."

Kurz's story is not unusual. Over the past few weeks, security guards have noticed an increase in vehicles failing to yield to bicyclists at SLAC's main gate. The majority of these safety concerns result from drivers not slowing down or not merging with enough care.

"To keep everyone safe, we ask both drivers and cyclists to be cautious when approaching the main gate," says Simon Ovrahim.

Ovrahim specifically asks drivers approaching SLAC from the west on Sand Hill Road to pay special attention to cyclists turning across traffic at Saga Lane into SLAC's main gate. Read more...

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