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In this issue:
Battling the Clouds
Science Today: BaBar Opens New Windows on Photon Annihilation
The Bell Tolls for Tea

SLAC Today

Thursday - July 13, 2006

(Photo - Mauro Pivi)
SLAC physicist Mauro Pivi and his colleagues are testing new technologies that may reduce the electron clouds in beam pipes. (Image courtesy of Diana Rogers.)

Battling the Clouds

Creating and then annihilating the tiniest and most powerful beams of electrons and positrons ever produced, the proposed International Linear Collider could open pathways to new particles, new dimensions, and new discoveries beyond our current imagination.

But clouds could block the view. Like clouds of ice crystals or condensed water droplets floating in the sky and blocking the sunshine, these clouds of electrons could dim the accelerator's brightness and block the view of new discoveries.

Within the global effort to make the ILC shine brightly, SLAC's Mauro Pivi wants to channel these electron clouds into a gutter inside the machine. Lanfa Wang, also of SLAC, wants to attract and dissipate them with an electrical charge. Each is clear about the stakes: prospects for building the multinational, multi-billion-dollar ILC depend significantly on its cost, and its cost depends in part on removing the clouds.  Read more in symmetry...

(Daily Column - Science Today)

BaBar Opens New Windows on Rare Hadronic Final States

(Image - Feynman Diagram) This Feynman Diagram shows a positron and an electron (left) colliding to form two virtual photons which then produce two quark-antiquark pairs (right).

Physicists are always on the lookout for the unexpected. BaBar was designed primarily for measurements of B mesons, but by virtue of the excellent luminosity provided by SLAC PEPII, new windows of unplanned physics are being opened.

In a paper recently submitted to Physical Review Letters, BaBar researchers report the first observation of the creation of just two particles through a new production mechanism. They observed an electron-positron annihilation that produced two virtual photons, which in turn produced just two particles. This two-virtual-photon-annihilation (TVPA) process is different from the process usually seen at BaBar, which is produced via one virtual photon.

These rare events are observed at a rate of a few out of one million of hadronic events recorded at BaBar. This is the first established evidence of the TVPA process, which is connected to several existing puzzles in hadronic production.

The clean observation from this measurement opened the door to a variety of measurements of rare hadronic final states, which can improve our knowledge on the intricate hadron production mechanism that is needed for many key precision measurements.

The Bell Tolls for Tea

(Image - KIPAC bell) Phil Marshall rings the KIPAC bell to announce teatime at the Fred Kavli Building.

Researchers in the Kavli building find their ears are ringing every day at four, when teatime is announced by the tea brewer sounding a marine bell.

After two years working in the central lab annex (building 84) with nowhere to congregate, KIPAC postdocs decided to start a daily teatime after the move.

"One of the things we were looking forward to with the new building is a place to get together," explains postdoc Phil Marshall.

The problem of busy researchers not remembering to convene at four was solved by the bell, a gift from the KIPAC postdocs.

"Teatime is a real benefit to research, giving us time to talk with people who work in similar projects," says Marshall.

Teatimers were so enthusiastic about the prospect that they installed the bell even before the building was dedicated.

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