IU professors document rare nuclear occurrence

A group of IU scientists is headed to the meeting of the American Physical Society in Philadelphia this weekend to present what they are hailing as groundbreaking experimental results.\nThe group will present data from an experiment in which fusion occurs between two nuclei of heavy hydrogen to form a nucleus of helium and an uncharged pion.\nAccording to Professor Edward Stephenson, leader of the research team, the pion is one of the subatomic particles responsible for the strong force that holds every nucleus together. \nScientists have attempted to discover this fusion process for 50 years, and Stephenson said his group is the first to do so. Stephenson said this fact alone makes Saturday's presentation exciting. \n"Searches for this reaction started in the 1950s," Stephenson said. \n"There have been several experiments since then searching for (this result) without success. This is the first public presentation of these results."\nStephenson, who has been working for the IU Cyclotron Facility in Bloomington since 1979, said the process of fusion would not occur at all except that nature allows a small violation known as charge symmetry.\n"What we're trying to do is find where charge symmetry comes from," Stephenson said.\nProfessor Andrew Bacher, one of the two spokesmen for the experiment along with Stephenson, said the results of the experiment will take years to fully study.\n"There will be continuing efforts on our part and the rest of the physics community to understand our results," Bacher said. \nTo better understand this process, a team of physics theorists is helping Bacher's group explore the results. One of these theorists, Professor Charles Horowitz, said his group has been making prediction models and comparing them to the actual results of the experiment.\n"We are trying to ensure that the measurement happens and what it means," Horowitz said. \nHorowitz gives praise to Stephenson and his group for their successful completion of the experiment.\n"We've been working for more than a decade to perfect this technique, and there's no where else in the world this measurement can be done," Horowitz said.\nIn order to gather the data, Stephenson's group worked in three teams of three around the clock in June and July of 2002. Stephenson said working on the project provided a very long period of uncertainty.\n"One of the things that sticks out in my mind even from the very beginning is that I considered this a very high risk experiment," Stephenson said. "That is, many things could have gone wrong so we couldn't make this measurement." \nStephenson gives credit to IU for the success of the project.\n"There are very few universities in the United States with a laboratory of this size and quality," Stephenson said. "This would not have happened had not the university helped."\nBacher said the experiment will have a lasting impact in the scientific community.\n"This is one of those experiments that really worked out best, and it will be in textbooks for years to come," Bacher said.