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The Honolulu Advertiser
Posted on: Monday, August 18, 2003

UH scientists find subatomic puzzle

By Jan TenBruggencate
Advertiser Science Writer

University of Hawai'i physicists have identified a new mystery in the mind-bending world of particle physics, which deals with that flock of subatomic particles called quarks, leptons, and, in this case, mesons.

Quarks are among the smallest known bits of matter. There are six kinds, plus six matching anti-matter quarks. Mesons are made up of a quark and an anti-quark, which is to say, a particle of matter and a particle of anti-matter. Since matter and anti-matter tend to destroy each other, mesons are gone in an instant.

There are different kinds of mesons depending on which quarks they contain. For the latest work, the researchers worked with "B" mesons, which survive a few trillionths of a second and weigh a little more than a helium atom.

To make B mesons, researchers caused beams of electrons and positrons — particles with the same mass but opposite charge of electrons — to collide. The result of the collisions is a pair of B mesons, one B meson and one anti-B meson. Since they survive so briefly, they can't be directly measured, but physicists can measure the decay products — what's left after the mesons break down.

Standard particle physics suggests that a unit of matter is equivalent but opposite to a unit of anti-matter. And when they meet, they ought to break down in a predictable way. The new research shows that sometimes B mesons decay in a different way than at other times.

That seems to contradict conventional models of particle behavior. It could also indicate that a new class of particles is involved, which "have been postulated but never seen," said a press release on the subject.

The physicists are very cautious about their findings, but suggest the research may "be hinting at the existence of supersymmetric particles or something even more exotic."

The University of Hawai'i High Energy Physics Group worked with other researchers at the KEKB accelerator at the Japanese High Energy Accelerator Research Organization in Tsukuba, Japan. They are part of the Belle collaboration, which includes 350 researchers in 11 countries.

Among the researchers are eight faculty and six graduate students who make up the University of Hawai'i High Energy Physics group. The faculty members are group head Stephen Olsen, Thomas Browder, Michael Jones, Michael Peters, Marc Rosen, Rolf Seuster, Karim Trabelsi and Gary Varner.

Browder presented the new work Tuesday at the XXI International Symposium on Lepton and Photon Interactions at High Energies, held at Fermilab near Chicago.

Reach Jan TenBruggencate at jant@honoluluadvertiser.com or (808) 245-3074.