Interactions News Wire
#38-05
17 May 2005
http://www.interactions.org*******************************************************************
Source:
University of Hawaii
Content: News Release
Date Issued: 17 May
2005
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Contact:
Stephen
Olsen, (808) 956-2929
Tom Browder, (808) 956-2936
Department of
Physics, UH Manoa
Uh Manoa Physicists Discover A New Sub-Atomic
ParticleThe “hybrid meson” may be the first found by scientists after
a search of 25 yearsHONOLULU – A team of physicists from the
University of Hawaii at Manoa, along with scientists from universities and
laboratories in America, Asia, Australia and Europe, recently reported the
discovery of an enigmatic and unexpected new sub-atomic particle called
Y(3940). The scientists are part of the “Belle experiment” and their
findings will be published in this month’s issue of Physical Review Letters, the
world’s premier physics journal.
The Belle experiment involves the study
of charge conjugation parity (CP) violation – the differences between matter and
antimatter. The experiment operates at the KEK High Energy Physics
Laboratory in Tsukuba, Japan, home to the world’s highest intensity particle
accelerator. The Hawaii group has been part of the project since 1994 when
preparations for the experiment started.
The newly observed Y(3940) is
very short-lived and quickly decays into two well-known particles, omega and
J/psi. All that is known about the sub-atomic particle to date hints at
the possibility that it may be an example of a so-called “hybrid meson,” a
particle that is assumed to be comprised of a quark, an antiquark and a
gluon. A gluon is a particle that mediates the very strong forces that
bind quarks together to form particles.
“The existence of hybrid
quark-antiquark-gluon particles was first predicted theoretically in 1978,” said
UH physicist Stephen Olsen. “However, in spite of 25 years of searching
for one, none have been seen, until, maybe now.”
Although many of the
properties of the Y(3940) match expectations for a hybrid meson, its mass, which
is about the same as a single atom of helium, is somewhat below theoretical
estimates. As a result, the interpretation of this new particle remains an
enigma. Further investigations of its properties, currently in progress,
should help clarify the situation.
The observation of the Y(3940) is the
result of analysis of Belle data by professors Stephen Olsen of the University
of Hawaii at Manoa and Sookyung Choi of Gyeongsang University in
Korea.
Other UH Manoa participants in the Belle experiment include
faculty members Tom Browder, Mike Jones, Mike Peters and Gary Varner;
postdoctoral researchers Marlon Barbero and Karim Trabelsi; and graduate
students Eric Dodson, Hulya Guler, Himansu Sahoo and Kirika Uchida. The
work by Hawaii physicists in the Belle experiment is supported in part by the
U.S. Department of Energy.