[Triumf-seminars] TRIUMF Seminar today at 14:00

Wed, 13 Apr 2005 05:00:01 -0700

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Date/Time: Wed 2005-04-13 at 14:00

Location:  Auditorium          

Speaker:   Erich Ormand (Lawrence Livermore National Laboratory)

Title:     First Principles Descriptions of Atomic Nuclei

Abstract: A long-standing goal of nuclear theorists has been to come to a fundamental understanding of the nucleus.By this, I mean starting from the basic inter-nucleon interaction, can we build complex nuclei, and arrive at a description that agrees with our experimental observations. While this may seem like a simple concept, it has eluded the nuclear physics community for the last fifty years. But now because of new ideas and recent advances in high-performance computing this goal is now beginning to be viable for nuclei up to around oxygen. I will outline the No-core Shell Model, which has become one of two methods to reach our goal of a first-principles description of nuclei. The No-core Shell Model is an ab initio application of the shell model utilizing effective interaction theory. I will show that the nucleon-nucleon interaction by itself not only fails to reproduce the binding energy of nuclei, but also substantially fails to describe the structure of low-lying nuclear states. This is clear and compelling evidence that three-nucleon (and maybe four-nucleon) interactions are a critical ingredient to describe nuclear structure. In addition to structure, it is also possible to extend the No-core Shell Model to dynamic properties of nuclei, namely their reactions. I will show prelimenary attempts to use the high quality structure results of the No-core Shell Model to compute S-factors important in astrophysics. I will conclude by outlining a research program for the future that will lead to improved descriptions of heavy nuclei, and an accurate description of clustering phenomena, and hopefully the famous triple-alpha and 12C+alpha reactions.

Theory Research Scientist Candidate

Stimulants available 15 minutes before the talk.

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