Color-flavor Locked Strangelets Research Articles

Color–flavor locked strangelets with confinement and perturbative interactions

The properties of color–flavor locked (CFL) strangelets are investigated with the latest quark mass scaling that includes both linear confinement and leading-order perturbative interactions. With a self-consistent thermodynamics, we find that the perturbative interaction increases CFL strangelets’ radius and energy per baryon, while the one-gluon-exchange interaction has the opposite effects. With the increasing of the baryon number [Formula: see text], the energy per baryon decreases the electric charge per baryon and approaches to zero eventually. Specially at comparatively large [Formula: see text], the electric charge is nearly proportional to the two-third power of [Formula: see text] with the proportional coefficient to be about half of that in the conventional bag model.

Color-Flavor Locked Strangelets in a New Quark Model with Linear Confinement and Coulomb-Type Interactions

The color-flavor locked (CFL) strangelets have been investigated in a new quark model with linear confinement and one-gluon-exchange interactions. Considering Coulomb energy, we have studied the properties of three kinds of CFL strangelets, namely, positively charged, negatively charged and nearly neutral CFL strangelets. It is found that the one-gluon-exchange effect lowers the energy of a strangelet considerably and thus makes it much more stable than without considering the effect. The charge of a positive strangelet is larger than 0.15A2/3 with A being the baryon number, but smaller than that in bag model. The charge of a negatively charged or nearly neutral CFL strangelet is nearly proportional to A1/3.

Surface effects in color superconducting strange-quark matter

Surface effects in strange-quark matter play an important role for certain observables which have been proposed in order to identify strange stars, and color superconductivity can strongly modify these effects. We study the surface of color superconducting strange-quark matter by solving the Hartree-Fock-Bogoliubov equations for finite systems (``strangelets'') within the MIT bag model, supplemented with a pairing interaction. Because of the bag-model boundary condition, the strange-quark density is suppressed at the surface. This leads to a positive surface charge, concentrated in a layer of $\ensuremath{\sim}1\text{ }\text{ }\mathrm{fm}$ below the surface, even in the color-flavor locked (CFL) phase. However, since in the CFL phase all quarks are paired, this positive charge is compensated by a negative charge, which turns out to be situated in a layer of a few tens of fm below the surface, and the total charge of CFL strangelets is zero. We also study the surface and curvature contributions to the total energy. Because of the strong pairing, the energy as a function of the mass number is very well reproduced by a liquid-drop type formula with curvature term.

COLOR-FLAVOR LOCKED STRANGELETS IN A QUARK MASS DENSITY-DEPENDENT MODEL

The color-flavor locked (CFL) phase of strangelets is investigated in a quark mass density-dependent model. Parameters are determined by stability arguments. It is concluded that three solutions to the system equations can be found, corresponding, respectively, to positively charged, negatively charged, and nearly neutral CFL strangelets. The charge to baryon number of the positively charged strangelets is smaller than the previous result, while the charge of the negatively charged strangelets is nearly proportional in magnitude to the cubic-root of the baryon number. However, the positively charged strangelets are more stable compared to the other two solutions.

STABILITY OF COLOR-FLAVOR LOCKED STRANGELETS

The stability of color-flavor locked (CFL) strangelets is studied in the three-flavor Nambu–Jona-Lasinio model. We consider all quark flavors to be massless, for simplicity. By making use of the multiple reflection expansion, we explicitly take into account finite size effects and formulate the thermodynamic potential for CFL strangelets. We find that the CFL gap could be large enough so that the energy per baryon number of CFL strangelets is greatly affected. In addition, if the quark–quark coupling constant is larger than a certain critical value, there is a possibility of finding absolutely stable CFL strangelets.

New solutions for the color–flavor locked strangelets

Recent publications rule out the negatively charged beta equilibrium strangelets in ordinary phase, and the color–flavor locked (CFL) strangelets are reported to be also positively charged. This Letter presents new solutions to the system equations where CFL strangelets are slightly negatively charged. If the ratio of the square-root bag constant to the gap parameter is smaller than 170 MeV, the CFL strangelets are more stable than iron and the normal unpaired strangelets. For the same parameters, however, the positively charged CFL strangelets are more stable.

Color-flavor locked strangelets.

Finite lumps of color-flavor locked strange-quark matter (CFL strangelets) are significantly more stable than strangelets without color-flavor locking for wide ranges of parameters, increasing the likelihood of strangelet metastability, or even absolute stability beyond some minimum baryon number A(min). Whereas bulk CFL strange-quark matter is electrically neutral, CFL strangelets are positively charged, with Z approximately 0.3A(2/3). This is quite different from "ordinary" strangelets and may provide a possible test of color-flavor locking if strangelets are detected in upcoming cosmic-ray space experiments.