118213659
Pion form factor in a scalar model
SummaryUsing as an example the simple scalar modelρ(6)3; we describe our method of analysing the bound-state form factors based on the systematic use of the alpha-representation for Feynman diagrams. The nature of «nonrenormalization group» logarithms specific for the form-factor-type problems is investigated. The summation of ladder contributions is performed in the leading-logarithm approximation.RiassuntoUsando come esempio il semplice modello scalareρ(6)3 si descrive il metodo di analizzare i fattori di forma dello stato legato basati sull’uso sistematico della rappresentazione alfa per i diagrammi di Feyman. Si studia la natura dei logaritmi del gruppo di non rinormalizzazione specifico di problemi di tipo fattore di forma. Si esegue la somma dei contributi di a gradini nell’approssimazione del logaritmo principale.РезюмеНа примере простой скалярной моделиρ(6)3 излагается метод анализа формфакторов составных систем, основанный на систематическом использовании альфа-представления фейнмановских диаграмм. Исследуется природа «неренормгрупповых» логарифмов, специфичных для задач формфакторного типа. Проведено суммирование лестничных вкладов в главном лограрифмическом приближении.
120815334
Local Quark - Hadron Duality and Nucleon Form-factors in {QCD}
Abstract Quark-hadron duality is incorporated to estimate the non-perturbative O(α 0 S -contribution to the nucleon form factors G N E,M ( t ). For 1 t 2 the results are in satisfactory agreement with the existing data. This means that the observed dipole behaviour of G N ( t ) has nothing to do with the short distance dynamics.
123206973
The interior of the charge transition density and the structure of low-lying states in deformed nuclei
The RPA calculations of charge transition densities (CTD) rho lambda mu nu (r) for the E2 transitions from the ground state to the low-lying Ipi Knu =2+2nu and 2+0nu states in 164Dy predict rather strong peaks of single-particle nature in the interior of the CTD. A simple explanation of the results is given. The reliability of the results obtained, their possible application to the study of the structure of low-lying states and some predictions for nuclei of the rare-earth region are discussed.
117583655
Overlap of metal clusters and nuclear structure physics
117621252
Exchange by the hard and soft quanta in the high energy scattering of particles
In the framework of the functional integration method in quantum field theory the method is proposed for constructing scattering amplitude of the particles which interact by means of the exchange of the infinite number of soft quanta and the finite number of hard virtual particles. In this method the form factors of the interacting particles arise in calculations of the scattering amplitude at large angles. It is in agreement with the Wu--Yang conjecture about the elastic form factor role in high energy scattering. (auth)
121516467
CollectiveEλ excitations of surface character in spherical and deformed sodium clusters: vibrating potential model
The self-consistent vibrating potential model (VPM) is extended for the description ofEλ surface collective excitations in alkali metal clusters with practically any kind of static deformation. The case of spherical clusters is also covered. Any single-particle potentials and valence electron densities for which the coefficients of the multipole expansion are known can be used within the model. The strength function method incorporated into the model allows one to avoid solving the equations for every state and, as a result, simplifies the calculations drastically. The model is of a quite general character and can also be used for description of giant resonances in atomic nuclei if the Coulomb terms are neglected. The VPM is applied to calculate theE1,E2 andE3 excitations in spherical (Na8, Na20 and Na40) and deformed (Na10, Na18 and Na26) clusters.
16328558
ZERO-POINT ENERGY OF A DILUTE DIELECTRIC BALL IN THE MODE SUMMATION METHOD
In the (e1-e2)2-approximation the Casimir energy of a dilute dielectric ball is derived using a simple and clear method of the mode summation. The addition theorem for the Bessel functions enables one to present in a closed form the sum over the angular momentum before the integration over the imaginary frequencies. The linear in (e1-e2)2 contribution into the vacuum energy is removed by an appropriate subtraction. The role of the contact terms used in other approaches to this problem is elucidated.