72,056 research outputs found
Chiral field theory of glueball
A chiral field theory of glueball is presented. By adding a
glueball field to a successful Lagrangian of chiral field theory of
pseudoscalar, vector, and axial-vector mesons, the Lagrangian of this theory is
constructed. The couplings between the pseodoscalar glueball field and mesons
are via U(1) anomaly revealed. Qualitative study of the physical processes of
the glueball of is presented. The theoretical
predictions can be used to identify the glueball.Comment: 29 page
Strangeness magnetic form factor of the proton in the extended chiral quark model
Background: Unravelling the role played by nonvalence flavors in baryons is
crucial in deepening our comprehension of QCD. Strange quark, a component of
the higher Fock states in baryons, is an appropriate tool to investigate
nonperturbative mechanisms generated by the pure sea quark.
Purpose: Study the magnitude and the sign of the strangeness magnetic moment
and the magnetic form factor () of the proton.
Methods: Within an extended chiral constituent quark model, we investigate
contributions from all possible five-quark components to and in the four-vector momentum range (GeV/c). Probability
of the strangeness component in the proton wave function is calculated
employing the model.
Results: Predictions are obtained without any adjustable parameters.
Observables and are found to be small and negative,
consistent with the lattice-QCD findings as well as with the latest data
released by the PVA4 and HAPPEX Collaborations.
Conclusions: Due to sizeable cancelations among different configurations
contributing to the strangeness magnetic moment of the proton, it is
indispensable to (i) take into account all relevant five-quark components and
include both diagonal and non-diagonal terms, (ii) handle with care the
oscillator harmonic parameter and the component
probability.Comment: References added, typos corrected, accepted for publication by Phys.
Rev.
Relative price variability and the Philips curve: Evidence from Turkey
We argue that relative price changes are a key component of the Phillips curve relationship between inflation and output. Building on work by Ball and Mankiw, we propose including measures of the variances and skewness of relative price adjustment in an otherwise standard model of the Phillips curve. We examine the case of Turkey, where distribution of price changes is especially skewed and where the existence of a Phillips curve has been questioned. We have two main findings: (i) inclusion of measures of the distribution of relative price changes improves our understanding of the Phillips curve trade-off; (ii) there is no evidence of such a trade-off if these measures are not included
Intrinsic charm content of the nucleon and charmness-nucleon sigma term
In the extended chiral constituent quark model, the intrinsic
content of the nucleon is investigated. The probabilities of the
quark-antiquark components in the nucleon wave functions are calculated by
taking the nucleon to be admixtures of three- and five-quark components, with
the relevant transitions handled {\it via} the P mechanism.
Predictions for the probability of the in the nucleon wave function
and the charmness-nucleon sigma term are presented. Our numerical results turn
out to be consistent with the predictions from various other approaches
reported in the literature.Comment: Accepted for publication in Phys. Rev.
Analysis and design of transonic airfoils using streamwise coordinates
A new approach is developed for analysis and design of transonic airfoils. A set of full potential equivalent equations in von Mises coordinates is formulated from the Euler equations under the irrotationality and isentropic assumptions. This set is composed of a main equation for the main variable, y, and a secondary equations for the secondary variable, R. The main equation is solved by type dependent differencing combined with a shock point operator. The secondary equation is solved by marching from a non-characteristic boundary. Sample computations on NACA 0012 and biconvex airfoils show that, for the analysis problem, the present approach achieves good agreement with experimental C sub p distributions. For the design problem, the approach leads to a simple numerical algorithm in which the airfoil contour is calculated as part of the flow field solution
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