U.S.-Czech Physics Research on Asymptotic Normalization Coefficients in Nuclear Astrophysics

Texas A&M Research Foundation, College Station TX

Investigators

Abstract

This US-Czech research project between Robert E. Tribble of Texas A&M's Cyclotron Institute with partner Vaclav Kroha at the Czech Nuclear Physics Institute, Rez, will apply techniques they developed to determine the direct capture contribution for a number of reactions that are important in the hydrogen-burning phase of stellar evolution. We know that stars evolve by burning their nuclear fuel through a sequence of reaction cycles and decays. The US-Czech team uses a novel indirect method to determine astrophysical capture reaction rates at stellar energies. Now published, that new approach, called the Asymptotic Normalization Coefficients (ANCs) method, is widely used by experimental groups. This phase of the collaboration involves further use of the ANCs method to study important stellar capture reactions in the hot CNO cycle, with the goal of understanding the evolution of supermassive stars. Both groups have core support from non-NSF sources. The NSF award supports the participation of graduate and undergraduate students from Texas A&M who will travel to the Nuclear Physics Institute for joint research and to learn about setup and operation of a gas cell at the Rez facility. The knowledge gained will enable them to carry out precision studies of ANCs with gas targets on the Texas MDM magnetic spectrometer and to perform data analysis. At the undergraduate level, the experience will contribute to work needed for completing an honors thesis. Much new information is now available from astronomical observations that require modeling of nuclear processes to understand. The synergy between observation, stellar modeling and nuclear physics that the US-Czech team brings to bear is expected to advance our understanding of stellar evolution. This nuclear astrophysics project thereby fulfills the program objective of advancing scientific knowledge by enabling experts in the United States and Central Europe to combine complementary talents and share research resources in areas of strong mutual interest and competence.