UH Physicists Part of International Team Presenting Indication of New Physics from the Belle Experiment

Team has evidence for new phenomenon that could challenge current particle physics theories

University of Hawaiʻi at Mānoa
Posted: Aug 19, 2003

The High Energy Accelerator Research Organization (KEK) recently announced that the Belle collaboration, an international research team working at the KEKB accelerator, found evidence for a new phenomenon that cannot be explained by the Standard Model of elementary particles. University of Hawaiʻi at Mānoa Professor Thomas Browder presented the Belle collaboration‘s evidence for this new phenomenon at the XXI International Symposium on Lepton and Photon Interactions at High Energies, an international conference held last week at Fermilab, a national lab near Chicago.

The Belle collaboration is an international research team, which includes a number of UH Mānoa researchers and graduate students, working at the KEKB accelerator located at the Japanese High Energy Accelerator Research Organization (KEK) in Tsukuba, Japan. Data has been collected using the Belle detector since 1999. The KEKB accelerator is a device for generating a large number (150 million to date) of very short-lived subatomic particles called B mesons as well as their anti-matter counterparts. These particles, each with a mass somewhat greater than that of the helium atom, disintegrate after a few trillionths of a second into lighter and more long-lived daughters, and these decay products are detected by the Belle detector.

Studies of B meson decays play a crucial role in the understanding of the origin of the tiny difference that is known to exist between matter and anti-matter, called CP violation. The first clear evidence that such CP violation occurs in B meson decays was reported two years ago by the Belle and the BaBar collaborations, the latter working at the Stanford Linear Accelerator Center in California. Since then, the Belle team has been expanding the scope of its investigation into the ways that CP violation might manifest itself. One of the new decay processes studied shows an amount of CP violation that differs from that seen in other B decays and thus could indicate the presence of new physics processes.

The Standard Model has enjoyed overwhelming success since it was conceived roughly 30 years ago. Although it is too soon to draw firm conclusions, Belle‘s new observation may impose a serious challenge to this theory if it is confirmed when additional data are acquired. Even as it now stands, it is the most serious discrepancy with the Standard Model, and may, for example, be hinting at the existence of supersymmetric particles or something even more exotic. Detailed investigations of this phenomenon and related processes with larger B meson samples are now a top priority in high energy physics.

The Belle collaboration is composed of 350 researchers from 55 institutions in 11 countries. The University of Hawaiʻi High Energy Physics group is one of the major groups in Belle, contributing eight faculty and six graduate students. In addition, two Hawaiʻi graduate students recently completed their theses and have moved to other research projects. One of the three Belle spokespersons is UH Mānoa Professor Stephen Olsen, who is also the head of the Hawaiʻi High Energy Physics Group. The other UH Mānoa faculty members are Thomas Browder, Michael Jones, Michael Peters, Marc Rosen, Rolf Seuster, Karim Trabelsi, and Gary Varner.

More details are available at the Belle collaboration web site — http://belle.kek.jp/

For more information, visit: http://belle.kek.jp/