Researchers make headway in neutrino study

Publish Date:06/13/03
Story Type:Economy;
Byline:Myra Lu

        After six years of painstaking work, researchers on the TEXONO project, or Taiwan Experiment on Neutrinos, have published the first results of what is admittedly a small experiment compared to what is being done at international laboratories. Nevertheless, the significance of the contribution for all the Chinese and Taiwanese scientists involved is no less evident.

        Neutrinos are one of the more than 20 fundamental particles that make up the universe. Scientists around the world have conducted numerous experiments to learn more about this particle, which remains one of the least understood. Neutrinos are produced in the Earth's atmosphere, the sun, particle accelerators and nuclear power reactors.

        Physicists believe that neutrino studies will help shed light on questions about the particle's mass and what roles they play in particle physics and cosmology.

        "Every particle has its own unique properties. We have been on the lookout for parameters that characterize neutrinos," said Henry Wong, associate research fellow at Academia Sinica and head of the TEXONO study.

        The joint project between China and Taiwan, Wong explained, has helped set a new upper limit to the neutrino magnetic moment, an indicator of the particle's inherent magnetism. The team has also accumulated data and provided an analysis of neutrino radiative decay. The research results were published recently in Physical Review Letters and have won the recognition of international counterparts.

        The experiment took place in a laboratory located within 28 meters from the core of a reactor at the Kuo-Sheng Nuclear Power Station in the suburb of Taipei. Scientists say the process of nuclear fission--from which nuclear energy is generated--releases a significant amount of neutrinos. This makes a reactor an ideal place for neutrino experiments. Wong's team will continue to use the site for studies on other neutrino properties and interactions as well as for the development of improved hardware.

        The fact that local scientists undertook such a project from scratch--from the design and construction of the detector apparatus to data analysis--seems all the more reason for good cheer even though the project is far smaller in scale and in scope than others being carried out in Japan and the United States.

        The team is made up of about 30 researchers from both Taiwan and China--a fraction of the size of international teams. Nevertheless, Wong stressed, "The major ingredients we use are the same as theirs. This has proved our capabilities in the research of particle physics." Petr Vogel, a physicist at the California Institute of Technology in Pasadena who specializes in neutrinos, was quoted in the U.S.-based Science magazine as saying that even though the results are not earth shattering, they are nevertheless important. The professor praised the TEXONO team for performing admirably given their budgetary constraints, especially since the project was the first particle physics experiment on the island.

        Taiwanese researchers began participating in particle physics experiments in the late 1980s. By the mid 1990s, they had already worked with such renowned institutes as Fermi National Accelerator Laboratory in the United States, National Laboratory for High Energy Physics in Japan and European Laboratory for Particle Physics in one form or another. They are responsible for a variety of tasks involving detectors, computer software, electronics and data analysis.

        "Over the past five years or so, we have seen many breakthroughs in neutrino physics, which overrule what is written in the science textbooks," Wong said. The results of international collaborations such as the Super-Kamiokande in Japan and Sudbury Neutrino Observatory in Canada gave the Taiwan project what Wong described as a "positive impact." This is because these earlier experiments have confirmed that the neutrino does have mass and that neutrino oscillation does take place. The latter refers to a phenomenon where neutrinos change from one type to another while traveling great distances. Such oscillation would not occur if neutrinos were entirely without mass, which scientists used to believe to be the case.

        "These experiments use much larger instruments to explore different aspects of the neutrino properties from those pursued by the TEXONO experiement. However, given their findings, we know there is a grander picture behind and which direction to go," Wong noted.

        In the West, a country's technological development has often been gauged by its ability to conduct basic scientific experiments. Since Taiwan's scientific community is comparatively small, it cannot begin to match up to the size of its foreign peers. But as Wong suggested, a small-scale experiment can be frontier as well.

        "Lacking the manpower to do large experiment is no excuse for not doing it. We can seek international cooperation in this regard, especially when the level of our professionalism is not that far behind that of the West," the neutrino scientist said.

        Likening collaboration in big scientific experiments to an orchestra, Wong was quick to attribute the achievement to the contributions of various experts, each playing their own instrument, but adding up to a melodic symphony. He credited the interdisciplinary nature of the joint effort by scientists across institutes and universities. "Taiwan researchers are irreplaceable in this project," he concluded.