NEW ASTROPHYSICS STUDY FINDINGS REPORTED FROM G.B. ALAVERDYAN AND CO-AUTHORS

Science Letter
May 19, 2009

According to a study from Yerevan, Armenia, "The equation of state
of neutron star matter is examined in terms of the relativistic
mean-field theory, including a scalar-isovector delta-meson effective
field. The constants of the theory are determined numerically so that
the empirically known characteristics of symmetric nuclear matter
are reproduced at the saturation density."

"The thermodynamic characteristics of both asymmetric nucleonic matter
and beta-equilibrium hadron-electron npe-plasmas are studied. Assuming
that the transition to strange quark matter is an ordinary first-order
phase transition described by Maxwell’s rule, a detailed study is made
of the variations in the parameters of the phase transition owing to
the presence of a delta-meson field. The quark phase is described using
an improved version of the bag model, in which interactions between
quarks are accounted for in a one-gluon exchange approximation,"
wrote G.B. Alaverdyan and colleagues (see also Astrophysics).

The researchers concluded: "The characteristics of the phase transition
are determined for various values of the bag parameter within the range
B a [60,120]MeV/fm(3) and it is shown that including a delta-meson
field leads to a reduction in the phase transition pressure P (0) and
in the concentrations n (N) and n (Q) at the phase transition point."

Alaverdyan and colleagues published the results of their research
in Astrophysics (Relativistic mean-field theory equation of state
of neutron star matter and a Maxwellian phase transition to strange
quark matter. Astrophysics, 2009;52(1):132-150).