Static properties of chiral soliton in a nonlinear σ-field with ρ-meson coupling

The soliton soluton for a lagrangian made of a nonlinear σ-field coupled to a ρ-meson field is studied. The static properties are calculated and compared with experimental values and the results of the Skyrme model.     

Stabilization of skyrmions via ϱ-mesons

It is shown that a skyrion can be stabilized by introducing ?-mesons into the chiral SU(2)_L × SU(2)_R lagrangian without higher-derivative terms like the Skyrme term. The ?-mesons are considered as dynamical gauge bosons associated with a hidden local symmetry of the non-linear sigma model. The lagrangian reduces to the Skyrme model in a limit of parameters. The Skyrmion mass M is found to be M = 1058 MeV when the parameters are fixed so as to satisfy the KSRF relation. It is also shown that a solition solution in a model with Ω-meson coupled with the baryonic current is a saddle-point solution.     

Effective chiral hadron lagrangian with anomalies and skyrme terms from quark flavour dynamics

By bosonization of an extended Nambu-Jona-Lasinio type of quark model with explicit breaking of chiral U(n) × U(n) symmetry we derive a effective low-energy lagrangian of composite scalar, pseudoscalar, vector and axial-vector mesons. This lagrangian contains the gauged Wess-Zumino term as well as higher order derivative terms of the Skyrme type, the coefficients of which agree with recent phenomenological estimates. In particular, the value predicted for the strength of the standard fourth-order Skyrme term is in satisfactory agreement with the results obtained by fitting the nucleon and delta masses. Our effective chiral lagrangian reproduces the wealth of the results of successful phenomenological lagrangians as, e.g. soft-pion theorems, Goldberger-Treiman relations, PCAC, the KSFR relation, the (approximate) Weinberg relation, etc. Moreover, the predicted mass spectra and decay constants of composite mesons are in qualitative agreement with the experimental findings. Furthermore, when electroweak interactions are included the lagrangian contains vector (axial-vector) dominance based on field-current identities.     

Evaluation of the Skyrme parameter from QCD sum rules

The dimensionless parameter of the Skyrme lagrangian is evaluated by two methods. In one a combination of sum rules for the nucleon and the pion is used, in the other only baryonic sum rules. e = 5−8 and e = 5−7 is found, respectively, in agreement with the phenomenological value e = 5.45. To leading order in the operator-product expansion the analytical expression of e does not depend on the chiral-symmetry-breaking parameters.     

Effective chiral meson lagrangian with Weinberg and KSFR relations from microscopic four-quark interactions

An effective chiral meson lagrangian is derived from a microscopic quark lagrangian. It contains a partial Higgs mechanism for ϱ-A₁ mass splitting reproducing Weinberg and KSFR relations, and includes quartic derivative “Skyrme” terms and the gauges Wess-Zumino term. The connection to previous approaches deriving the effective lagrangian exclusively from the chiral anomaly including “normal-parity” terms is established.     

Baryon masses in the skyrme Yang-Mills model

The predictions concerning solitonic baryon masses in the general nonlinear chiral SU₂×SU₂ invariant Yang-Mills lagrangian for pions and ϱ-mesons are obtained. It is found that the predictions of this Skyrme Yang-Mills models are almost identical to the corresponding predictions of the original Skyrme model.     

The skyrmion-skyrmion interaction

Using the Skyrme effective lagrangian, baryons emerge as topological solitons. This effective lagrangian is used in adiabatic calculations aimed at providing an essentially parameter-free model of the interaction between such solitons. The resulting skyrmion-skyrmion interaction can be understood as terms simulating the exchange of π-, ρ-, and ω-mesons between the solitons. It is readily transformed (by essentially projective techniques) into a low-energy nucleon-nucleon potential. Comparisons of this potential with the best available semiphenomenological nucleon-nucleon interactions are found to be successful at the 30% level. Similarities between the Skyrme model and the quark chiral-bag model are discussed.     

Derivation of the skyrme lagrangian

The form as well as the strength of the quartic term in the Skyrme lagrangian are obtained from the general nonlinear chiral SU₂ × SU₂ invariant π-N-ϱ lagrangian suggested earlier. The agreement with experiment is excellent.     

Comparison between global phenomenological and microscopic optical potentials for proton as projectile below 100 MeV

For 112 target nuclei (52 elements) with proton as projectile, we calculate the reaction cross sections and elastic scattering angular distributions, as well as the X2 values for 16 kinds of proton optical model potentials: two sets of phenomenological global optical potentials and the microscopic optical potentials proposed by Shen et al for 14 sets of Skyrme force parameters: GSI-6, SBJS, SKM, SGI-Ⅱ, SKa-b, SG01-Ⅱ.We find that for obtaining the proton microscopic optical potential based on the nuclear matter approach with Skyrme force, SGI, SKa and SKb are the three sets of optimal Skyrme force parameters.     

The manifold of solutions of Roy's S- and P-wave equations for pion-pion scattering: The neighbourhood of the physical amplitudes

We study the solutions of the coupled S- and P-wave Roy equations for low-energy pion-pion scattering which are in the neighbourhood of a given solution. We give a general method for constructing these solutions for fixed inelasticities and driving terms and variable S-wave scattering lengths. In the case of the neighbourhood of the physical amplitudes, our procedure leads to a seven-dimensional manifold of solutions. If we omit variations affecting only the I = 0 S-wave around the $\text{K}\text{K}$ threshold, the number of dimensions is reduced to five, in accordance with the results of the phenomenological analysis of low-energy pion-pion scattering. Our solutions allow a study of the correlations between S- and P-waves implied by the Roy equations. This work completes a previous one dealing with the single-channel problem of the I = 1 P-wave.     

Zur Analytizität der Streuamplitude und Unitarität des Streuoperators bei der π-π-Wechselwirkung

The limitations which unitarity imposes on the magnitudes of the residues for the scattering amplitude in an effective range treatment of pion-pion scattering are investigated. The conditions (5) and (6) are derived.     

Coaxial Waveguide Slot Bridge Cell for Liquid Substances Study

The experimental method suggested suppose the studying of energy characteristics of slot bridge (SB) cells in the multi mode operating regime based on the preliminary numerical investigation of scattering resonant characteristics of SB (solution of boundary value problem and investigation of eigen frequencies and relevant field modes). The configuration of experimental model of SB cell is computed accordingly to required frequency band and preliminary information about dielectric parameters of materials chosen for tests. Ethanol scattering characteristics of SB cell are computed by software, developed on the base of rigorous solution of the boundary value problem, providing numerical data with any required accuracy.     

The B=2 sector of the Skyrme model in S3(L)

We consider baryon-number-two solutions to the Skyrme effective lagrangian on the surface of a hypersphere, S₃(L). At high densities we find solutions with “radially” uniform energy and baryon densities analogous to solutions previously found for the baryon-number-one problem on S₃(L) and for the dense matter problem in R₃. The density for this phase transition is essentially the same in the three cases. An interpretation of this phase transition as a simulation of “deconfinement” is offered.     

Pion-pion scattering lengths from Veneziano formula and η→3π,K→3π decays

Theη→ 3π decay amplitude is factorized into (a) the transition matrix element fromη toπ ⁰ and (b) Lovelace's expression of the Veneziano type for the pion-pion scattering amplitude. (a) is related with the electromagnetic mass splitting betweenK ⁺ andK ⁰. The absolute value of (b) is then obtained by fitting theη decay width. The pion-pion scattering lengths from (b) are reasonable. Since the analogous treatment ofK→ 3π decay together with a soft-pion determination of theK→π transition matrix element yield very small scattering lengths we suggest that theK→2π transition matrix element depends strongly on the pion masses.     

Isoscalar charge radius of the chiral bag

We calculate the contribution of the fermionic vacuum in the bag to the isoscalar charge radius (ICR) of the baryon. ICR can be evaluated as a function of the bag radiusR, the chiral angle θ at the surface of the bag and the parameters characterizing outer pion cloud, e.g.e andF _π in the Skyrme lagrangian.     

Features of the π0π0 system produced in 5π final states by 3.5 GeV/cπ+

Angular correlations between two pions in the 5-pion final states are studied. A comparison between neutral, like-charged and unlike-charged pion-pion system is done. Evidence is shown for a strong π⁰π⁰ correlation in the asymmetry parameters as well as in the mass distribution. This effect is interpreted in terms of the scattering length approximation.