Superconducting K strings in high density QCD

Recently it has been argued that the ground state of high density QCD islikely be a combination of the CFL-phase along with condensation of the K^0field. This state spontaneously breaks a global U(1)_Y symmetry, therefore onewould expect the formation of U(1)_Y global strings. We discuss the corestructure of these strings and demonstrate that under some conditions theglobal U(1)_Y symmetry may not be restored inside the string, in contrast withthe standard expectations. Instead, K^+ condensation occurs inside the core ofthe string if a relevant parameter \cos\theta_K = \mkzero^2/\mu_eff^2 is largerthan some critical value \theta_K > \theta_crit. If this phenomenon happens,the U(1)_Y strings become superconducting and may considerably influence themagnetic properties of dense quark matter, in particular in neutron stars.Comment: 10 pages, 2 Postscript figures. Discussion improved and acknowledgement adde