Results 1 - 10 of 1011
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[en] By differentiating the dressed quark propagator with respect to a variable background field, the linear response of the dressed quark propagator in the presence of the background field can be obtained. From this general method, using the vector background field as an illustration, we extract a general formula for the four-quark condensate (0-tilde|: q-bar (0)γμq(0) q-bar (0)γμq(0):|0-tilde). This formula contains the corresponding fully dressed vector vertex. We use this formula to analyze the factorization problem of the four-quark condensate and show that in the bare vertex approximation factorization holds exactly.
[en] The magnetic susceptibility of the quark condensate and the light-cone photon distribution amplitude of the leading twist is studied in the leading order of the perturbative expansion within the nonlocal condensates framework.
[en] By differentiating the inverse dressed quark propagator at finite chemical potential μ with respect to μ, the linear response of the dressed quark propagator to the chemical potential can be obtained. From this we extract a model-independent formula for the linear chemical potential dependence of the in-medium two-quark condensate and show by two independent methods (explicit calculation and Lorentz covariance arguments) that the first-order contribution in μ to the in-medium two-quark condensate vanishes identically. Therefore if one wants to study the in-medium two-quark condensate one should expand to at least the second order in the chemical potential μ.
[en] The interaction of light quarks and instanton liquid is analyzed at finite density of quark/baryon matter and in the phase of nonzero values of diquark (color) condensate. It is shown that instanton liquid perturbation produced by such an interaction results in an essential increase of the critical value of quark chemical potential μc which provokes the perceptible increase of quark matter density around the expected onset of the color superconductivity phase
[ru]Рассмотрено взаимодействие легких кварков и инстантонной жидкости при отличной от нуля плотности кварковой/барионной материи в фазе с ненулевым значением дикваркового конденсата. Показано, что учет соответствующего возмущения инстантонной жидкости приводит к существенному увеличению критического химического потенциала кварков μc, что в свою очередь вызывает заметное повышение пороговой плотности кварковой материи, при которой следует ожидать возникновение цветной сверхпроводимости
[en] We will give an introduction to the concept of quarkyonic matter, presenting an overview of what is meant by this term in the literature. We will then argue that the quarkyonic phase, as defined in the original paper, is a percolation-type phase transition whose phase transition line is strongly curved in ρB − Nc space, where NC is the number of colors and ρB the baryon density. With a toy model estimate, we show that it might be possible to obtain a percolating but confined phase at Nc = 3, Nf = 2 at densities larger than one baryon per one baryon size. We conclude by discussing how this phase can be observed at FAIR.
[en] The properties of quark condensates in static non-Abelian fields of the chromomagnetic types are investigated. The dependence of the condensate on the field strength and the temperature is discussed. It is shown that the principal term of the asymptotic expansion for all the investigated field types has the form ∼θ-2 in the high-temperature limit. An expansion is obtained for the quantity < bar qq> in the limit of an arbitrary, uniform, weak field for T = 0 and at finite temperature
[en] The pion production by sigma decay in hot and dense matter in the framework of the Nambu-Jona-Lasinio model  is investigated. The kinetic equation for joint evolution of pions and sigmas is constructed. The pion enhancement due to additional sigma creation via inertial mechanism is calculated.
[en] The paper is focused on calculating the finite temperature and quark/baryon chemical potential dependencies of the quark condensate and the π-and σ-meson masses in the subcritical region in the instanton model of the QCD vacuum. The impact of phononlike excitation of instanton liquid on the characteristics of the σ meson in such an environment is also examined.