Among the topics of my current interest are the following three:
When the atomic nucleus is probed in experiments that involve
large momentum transfers, one often observes
unusual phenomena indicating that the nucleus is more than a simple aggregate
of protons and neutrons, i.e., the nucleus has
non-nucleonic degrees of freedom.
Guided by the chiral symmetry requirements of strong interactions, we are
investigating when and how
effective meson degrees of freedom of the nucleus
(exchange currents) can be observed.
During a supernova explosion nuclear matter is compressed to high
densities (tightly packed protons and neutrons). From reasonable theoretical
extrapolations it is expected that a strange meson condensate can form
at these high nuclear densities. We are examining the dynamics leading
to a possible formation of a meson condensate. Since nucleons consist
of confined quarks, another question of importance at high nuclear densities
is how and under what conditions these quark
degrees of freedom affect nuclear observables.
Antimatter interactions with matter is a violent process. Symmetry
arguments indicates that the long range forces between
two nucleons imply attactive
long range nucleon-antinucleon forces.
However, at short nucleon antinucleon distances the annihilation
process dominates. The annihilation process converts mass to energy and
is closely connected to the quark and antiquark structure of the
nucleon and antinucleon. This matter-antimatter annihilation
process produces a large number of energetic mesons. We investigate
the annihilation process making use of
effective theories and phenomenological quark models.
Selected Publications
"gTwo-pion-exchange
contribution to the pp to ppπ0 reaction",
Y. Kim, T. Sato, F. Myhrer and K. Kubodera. Phys Lett B 657, 187 (2007)
"The effect of Kaon
Condensation on Quark-Antiquark Condensate in Dense Matter",
Y. Kim, K. Kubodera, D.-P. Min, F. Myhrer and M. Rho, Nucl. Phys. A 792, 249 (2007)
"Electromagnetic decay of
Λ(1520)", F. Myhrer,
Phys. Rev. C 74, 065202 (2006).
"Neutron beta-decay in
effective field theory", S. Ando, H.W. Fearing, V. Gudkov, K.
Kubodera, F. Myhrer, S. Nakamura and T. Sato, Physics Letters B
595, 250 (2004).
