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Title: Goldstone boson currents in a kaon condensed color-flavor locked phase

Abstract

We study the stability of the kaon condensed color-flavor locked (CFL) phase of dense quark matter with regard to the formation of a nonzero Goldstone boson current. In the kaon condensed phase there is an electrically charged fermion which becomes gapless near {mu}{sub s}{sup (1)}{approx_equal}1.35{delta} and a neutral fermion which becomes gapless near {mu}{sub s}{sup (2)}{approx_equal}1.61{delta}. Here, {mu}{sub s}=m{sub s}{sup 2}/(2p{sub F}) is the shift in the Fermi energy due to the strange quark mass m{sub s} and {delta} is the gap in the chiral limit. The transition to the gapless phase is continuous at {mu}{sub s}{sup (1)} and first order at {mu}{sub s}{sup (2)}. We find that the magnetic screening masses are real in the regime {mu}{sub s}<{mu}{sub s}{sup (2)}, but some screening masses are imaginary for {mu}{sub s}>{mu}{sub s}{sup (2)}. We show that there is a very weak current instability for {mu}{sub s}>{mu}{sub s}{sup (1)} and a more robust instability in a small window near {mu}{sub s}{sup (2)}. We show that in the Goldstone boson current phase all components of the magnetic screening mass are real. There is a range of values of {mu}{sub s} below 2{delta} in which the magnetic gluon screening masses are imaginary but themore » phase is stable with respect to electrically neutral fluctuations of the gauge field.« less

Authors:
; ;  [1];  [2]
  1. Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
21020059
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 75; Journal Issue: 5; Other Information: DOI: 10.1103/PhysRevD.75.054012; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ALGEBRAIC CURRENTS; CHIRALITY; COLOR MODEL; FLAVOR MODEL; GAUGE INVARIANCE; GLUONS; GOLDSTONE BOSONS; KAONS; QUANTUM FIELD THEORY; QUARK MATTER; REST MASS; S QUARKS

Citation Formats

Gerhold, A., Schaefer, T., Kryjevski, A., and Nuclear Theory Center, Indiana University, Bloomington, Indiana 47408. Goldstone boson currents in a kaon condensed color-flavor locked phase. United States: N. p., 2007. Web. doi:10.1103/PHYSREVD.75.054012.
Gerhold, A., Schaefer, T., Kryjevski, A., & Nuclear Theory Center, Indiana University, Bloomington, Indiana 47408. Goldstone boson currents in a kaon condensed color-flavor locked phase. United States. doi:10.1103/PHYSREVD.75.054012.
Gerhold, A., Schaefer, T., Kryjevski, A., and Nuclear Theory Center, Indiana University, Bloomington, Indiana 47408. Thu . "Goldstone boson currents in a kaon condensed color-flavor locked phase". United States. doi:10.1103/PHYSREVD.75.054012.
@article{osti_21020059,
title = {Goldstone boson currents in a kaon condensed color-flavor locked phase},
author = {Gerhold, A. and Schaefer, T. and Kryjevski, A. and Nuclear Theory Center, Indiana University, Bloomington, Indiana 47408},
abstractNote = {We study the stability of the kaon condensed color-flavor locked (CFL) phase of dense quark matter with regard to the formation of a nonzero Goldstone boson current. In the kaon condensed phase there is an electrically charged fermion which becomes gapless near {mu}{sub s}{sup (1)}{approx_equal}1.35{delta} and a neutral fermion which becomes gapless near {mu}{sub s}{sup (2)}{approx_equal}1.61{delta}. Here, {mu}{sub s}=m{sub s}{sup 2}/(2p{sub F}) is the shift in the Fermi energy due to the strange quark mass m{sub s} and {delta} is the gap in the chiral limit. The transition to the gapless phase is continuous at {mu}{sub s}{sup (1)} and first order at {mu}{sub s}{sup (2)}. We find that the magnetic screening masses are real in the regime {mu}{sub s}<{mu}{sub s}{sup (2)}, but some screening masses are imaginary for {mu}{sub s}>{mu}{sub s}{sup (2)}. We show that there is a very weak current instability for {mu}{sub s}>{mu}{sub s}{sup (1)} and a more robust instability in a small window near {mu}{sub s}{sup (2)}. We show that in the Goldstone boson current phase all components of the magnetic screening mass are real. There is a range of values of {mu}{sub s} below 2{delta} in which the magnetic gluon screening masses are imaginary but the phase is stable with respect to electrically neutral fluctuations of the gauge field.},
doi = {10.1103/PHYSREVD.75.054012},
journal = {Physical Review. D, Particles Fields},
number = 5,
volume = 75,
place = {United States},
year = {Thu Mar 01 00:00:00 EST 2007},
month = {Thu Mar 01 00:00:00 EST 2007}
}
  • We find that for a large enough strange quark mass, m{sub s}{sup 2}/4{mu}{delta}>2/3(1-0.023) ({mu} is the quark number chemical potential, {delta} is the superconducting gap), the kaon condensed color flavor locked (CFL) phase of asymptotically dense strongly interacting 3 flavor quark matter is unstable with respect to spontaneous generation of currents of Nambu Goldstone bosons due to spontaneous breaking of baryon number symmetry and hypercharge symmetry in the CFLK{sup 0} ground state. The total baryon and hypercharge currents vanish in the ground state. We find that CFLK{sup 0} and the new state are separated by a first order phase transition.more » The result is derived in the mean field approximation of high density effective theory with electromagnetic interactions turned off.« less
  • We investigate the color-singlet order parameters and the quark description of the Nambu-Goldstone (NG) bosons in the color-flavor locked (CFL) phase. We put emphasis on the NG boson (phason) called H associated with the U{sub B}(1) symmetry breaking. We qualitatively argue the nature of H as the second sound in the hydrodynamic regime. We articulate, based on a diquark picture, how the structural change of the condensates and the associated NG bosons occurs continuously from hadronic to CFL quark matter if the quark-hadron continuity is realized. We sharpen the qualitative difference between the flavor octet pions and the singlet phason.more » We propose a conjecture that superfluid H matter undergoes a crossover to a superconductor with tightly bound diquarks, and then a crossover to superconducting matter with diquarks dissociated.« less
  • The properties of the pseudoscalar Goldstone bosons in the color-flavor locked phase at moderate densities are studied within a model of the Nambu-Jona-Lasinio type. The Goldstone bosons are constructed explicitly by solving the Bethe-Salpeter equation for quark-quark scattering in random phase approximation. The main focuses of our investigations are (i) the weak decay constant in the chiral limit (ii) the masses of the flavored (pseudo)Goldstone bosons for nonzero but equal quark masses (iii) their masses and effective chemical potentials for nonequal quark masses, and (iv) the onset of kaon condensation. We compare our results with the predictions of the low-energymore » effective field theory. The deviations from results obtained in the weak-coupling limit are discussed in detail.« less
  • We calculate the kaonic contribution to the shear viscosity of quark matter in the kaon-condensed color-flavor-locked phase (CFL-K0). This contribution comes from a light pseudo-Goldstone boson that arises from the spontaneous breaking of the flavor symmetry by the kaon condensate. The other contribution, from the exactly massless superfluid 'phonon', has been calculated previously. We specialize to a particular form of the interaction Lagrangian, parameterized by a single coupling. We find that if we make reasonable guesses for the values of the parameters of the effective theory, the kaons have a much smaller shear viscosity than the superfluid phonons but alsomore » a much shorter mean free path, so they could easily provide the dominant contribution to the shear viscosity of CFL-K0 quark matter in a neutron star in the temperature range 0.01 to 1 MeV (10{sup 8} to 10{sup 10} K).« less