Half-Skyrmions and the Equation of State for Compact-Star Matter. (arXiv:1207.0429v1 [nucl-th] CROSS LISTED)

Half-Skyrmions and the Equation of State for Compact-Star Matter. (arXiv:1207.0429v1 [nucl-th] CROSS LISTED):
The half-skyrmions that appear in dense baryonic matter when skyrmions are
put on crystals modify drastically hadron properties in dense medium and affect
strongly the nuclear tensor forces, thereby influencing the equation of state
(EoS) of dense nuclear and asymmetric nuclear matter. The matter comprised of
half skyrmions has vanishing quark condensate but non-vanishing pion decay
constant and could be interpreted as a hadronic dual of strong-coupled quark
matter. We infer from this observation a set of new scaling laws -- called
"new-BR" -- for the parameters in nuclear effective field theory controlled by
renormalization-group flow. They are subjected to the EoS of symmetric and
asymmetric nuclear matter, and are then applied to nuclear symmetry energies
and properties of compact stars. The changeover from the skyrmion matter to a
half-skyrmion matter that takes place after the cross-over density $n_{1/2}$
makes the EoS stiffer and leads to a compact star as massive as $\sim
2.4M_\odot$. Cross-over density in the range $ 1.5n_0 \lsim n_{1/2} \lsim 2.0
n_0$ has been employed, and the differences between the EoSs before and after
this density and the dependence of our results on $n_{1/2}$ are discussed. The
novel structure of the EoS obtained with the new-BR scaling is relevant for
neutron-rich nuclei and compact star matter and could be studied in RIB (rare
isotope beam) machines.