Updated collider produces particle results in Beijing

August 29th, 2008  |  by  |  Published in Research News

BES III detector

BES III detector

University of Hawaiʻi physicists and their Chinese partners celebrated the successful operation and first events produced by a new particle collider and detector at the Institute of High Energy Physics in Beijing during summer 2008.

The accelerator, 100 times more powerful than its predecessor, sends electrons head-on into anti-electrons within a vacuum tube threaded through a ring of powerful electro–magnets at the Beijing Electron Positron Collider. The occasional collision—now a hundred–times more frequent—produces a charmed quark and its anti–matter counterpart.

The detector, called the Beijing Electron Spectrometer, identifies the quickly decaying quarks by measuring the energy and velocity of more conventional resulting particles.

Physicists from UH Mānoa’s High Energy Physics Group contributed a laser and fiber optic calibration system built in Hawaiʻi for the latest spectrometer experiment, BES III. In the initial test run on July 19, 2008, a pair of charmed particles, where one contains a c- quark and the other a c-quark was recorded in the detector approximately every 10 minutes.

The collision rate in the initial test run was about a factor of 4,000 times slower that the project’s ultimate design goal of six or seven charmed-particle pairs per second. Researchers purposely limited the intensity of the electron and positron beams in order to avoid possible damage to the very sensitive detection sensors of the BES-III spectrometer while they made sure that everything is working as expected.

The next day, intensities were increased and a 10-times higher collision rate was measured. Scientists plan to gradually increase the beam intensity over the following weeks while adjusting and calibrating BES-III’s nearly 20,000 detection elements. The BES-III research program is expected to begin in fall 2008.

“These developments greatly increase our capabilities at a time when this type of research at most U.S. facilities has been shut down,” says UH Professor of Physics Fred Harris, experiment co-spokesman. “When fully operational this fall, this will be the world’s premier facility for studying properties of the charmed quark.”

Collaborating scientists from around the world anticipate a 10-year program of intensive research that could revise conventional understanding of the fundamental building blocks of matter.

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