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Hossein Sadeghi

Hossein Sadeghi

Arak University, Iran

Title: Light nuclei formation in astrophysical energies evolution and settler

Biography

Dr. Sadeghi received his B. S., M. S. and Ph. D. degrees in theoretical physics from The University of Tehran, Tehran, Iran, in 1997, 2000 and 2005, respectively. He is currently an associate professor in the Physics Department of The Arak University. His past works were radiative capture of neutron or proton by deuteron in big-bang nucleosynthesis using effective field theory. He recently works on nuclear low-energy radiative reactions involving few-nucleon systems with two- and three-body electromagnetic current conservation. Dr. Sadeghi has worked in many research areas of physics and astrophysics, he has published 50 papers in international journals. In addition, he has been as a plenary speaker in several conferences around the world.

Abstract

The spectra of light nuclei provide the first test of nuclear interaction models. The reaction amount determines the relative abundance of most elements in red giant stars, neutron stars and black holes. Only if the structures are well simulated can one expect to calculate accurately observables at settler energies. Hydrogen based reactions in a star are the most efficient because of the small Coulomb barrier between participants. As the hydrogen supply is exhausted, other reaction pathways must be found to keep the star burning. The next most likely reactions involve the burning of helium nuclei, again because of the Coulomb barrier. During helium burning in a red giant star, many nuclear reactions are competing for the helium nuclei: the triple-alpha process, which fuses 3-alpha cluster nuclei into carbon, and the other one combines the carbon with another alpha particle to produce 16O or the alpha-12C radiative capture reaction. Our knowledge of this radiative capture rate at stellar energies is only restricted to the result of a very uncertain extrapolation from high energy measurements. This causes large uncertainties in our understanding of astrophysical processes that depends on this radiative capture reaction, including supernovas explosions. On the basis of the one-, two-, three- and four-alpha model, the radiative capture processes are investigated by using the many-body cluster models as well as the two- and three-body electromagnetic current conservation.