Electroexcitation of nucleon resonances

In these lectures the status of electromagnetic excitation of nucleon resonances is reviewed and some of the open problems of the structure and spectroscopy of light-quark baryons are discussed. The basic formalism for describing electromagnetic processes is introduced but not derived.Lecture given at the 8th Summer School on Intermediate-Energy Physics: Hadron Dynamics at Low and Intermediate Energies, Prague, July 10–14, 1995.     

Influence of a background gas on expanding plasma clots

An expansion of finite plasma clots into the background neutral gas is studied numerically. The presented model includes the quasineutrality violation as well as the interpenetration of plasma and neutral gas at the boundary of the plasma. We estimate the region of plasma parameters where the model is correct. Space distributions of main plasma parameters, cooling of electrons and the process of inter-penetration of the plasma and the neutral gas are analysed as well as an empiric formula for electron temperature is found. Finally, it is shown that the most intensive plasma-gas inter-penetration occurs in the case where the initial plasma and gas densities are the same.     

The local characteristics of the bound states of muonic molecules

The sticking probabilities ^Jv,G- and-factors for all bound states of mesic molecules ppµ, pdµ, ptµ, ddµ, dtµ, and ttµ withJ=0 andv=0, 1 have been calculated in the adiabatic hyperspherical approach (AHSA).     

Observation of Δn=1 dielectronic recombination resonances of boronlike argon

We report here an observation ofn=1 dielectronic recombination resonances of boron-like argon in the energy region 140–195 eV. With the cooler's electron beam as a target, a resolution of approximately 0.6 eV FWHM was obtained in the observed energy range. The energies of the doubly excited states were estimated with a Hartree-Fock calculation, which indicates that the observed resonances are from Ar¹³⁺(1s²2s²2p) to Ar¹²⁺(1s²2s²3l3l) and Ar¹²⁺(1s²2s2p3l3l) transitions.     

Sharp determinants

We introduce a sharp trace Tr^# and a sharp determinant Det^#(1-z) for an algebra of operators acting on functions of bounded variation on the real line. We show that the zeroes of the sharp determinant describe the discrete spectrum of . The relationship with weighted zeta functions of interval maps and Milnor-Thurston kneading determinants is explained. This yields a result on convergence of the discrete spectrum of approximated operators.Oblatum 8-V-1995 & IX-1995On leave from CNRS, UMR 128, ENS Lyon, France     

Semileptonic decays B → (π, )eν in relativistic quark model

Quark model results for the B → π, decays are analysed, making use of the dispersion formulation of the model: The form factors at q² > 0 are expressed as relativistic invariant double spectral representation over invariant masses of the initial and final mesons through their light-cone wave functions. The dependence of the results on the quark model parameters is studied. For various versions of the quark model the ranges

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,

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, and Γ_L/Γ_T = 0.7 ± 0.08 are found. The effects of the constituent quark transition form factor are briefly discussed.     

Analysis and design of highly broad-band,planar evanescent couplers

It is shown that by taking advantage of the maximum in the spectral dependence of the coupling coefficient, very broad-band symmetric and asymmetric single-mode planar couplers can be designed. The symmetric coupler allows at least 95.6% coupling between the two cores over the wavelength range 1.3–1.58 m, while the asymmetric coupler can act as a 3 dB splitter with only ±1.6% variation in the splitting ratio over the wavelength range 1.3–1.67 m. In both cases, the design includes the curved input-output arms, and the estimated bend loss is approximately 0.1 dB.     

Influence of mixture design on multivariate prediction of PAHs in mixture spectra

This work describes a simulation study aimed at establishing the impact of mixture design on the prediction ability of PLS regression models. Data sets are formed by multiplying UV absorbance spectra of 12 PAHs by their concentration profiles. In these case studies, either all possible mixtures of 1-12 components are used or randomly chosen selections of the mixtures. The effects of the number of samples and the number of concentration levels in the mixture designs on the results of the calibration are assessed. Comparisons are made between models formed using orthogonal fractional factorial mixture designs and those based on random designs. The applicability limits of the orthogonal designs are analysed in terms of actual concentration ranges of individual components in the mixtures.