Analysis of the spectrum of the Zn-like Kr VII ion: Highly excited 4<Emphasis Type="Italic">p</Emphasis>4<Emphasis Type="Italic">d</Emphasis> and 4<Emphasis Type="Italic">p</Emphasis>5<Emphasis Type="Italic">s</Emphasis> configurations

The spectrum of the Zn-like Kr VII ion, excited in a capillary discharge and recorded with a high resolution in the wavelength range of 300–1000 Å, was studied. Previously performed identification of the transitions from the levels of the 4s4f, 4s5s, 4s5p, and 4s5d configurations is confirmed and extended, and the energies of these levels are specified. The (4p ²+4s4d)?4p4d and (4p ²+4s5s)?4p5s transitions are identified for the first time, and the energies of all the levels of the 4p4d and 4p5s configurations are determined. The results of the analysis performed are confirmed by semiempirical calculations in terms of the Hartree-Fock method. These results are also shown to conform to the experimental data obtained for lighter ions of the Zn I isoelectronic sequence.     

Experimental lifetimes of some levels belonging to the 4<Emphasis Type="Italic">p</Emphasis><Superscript>4</Superscript>5<Emphasis Type="Italic">p</Emphasis> configuration of KrII using the cascade-photon-coincidence technique

Lifetimes of three levels belonging to the 4p ⁴5p configuration of singly ionized krypton have been measured using the cascade-photon-coincidence technique. The measurements have been performed under experimental condition where pressure dependent effect as well as other systematic errors are very small. The results have been compared with other experimental and theoretical values.     

Double exchange in cubic crystals with pairs of exchange-coupled mixed-valence 3<Emphasis Type="Italic">d</Emphasis><Superscript>3</Superscript>-3<Emphasis Type="Italic">d</Emphasis><Superscript>4</Superscript> ions

Specifics of the exchange interaction in mixed-valence Cr²⁺–Cr³⁺ 3d-ion pairs in KZnF₃ crystals are studied. It is shown that the double-exchange interaction can be significantly reduced by the low-symmetry crystal field created by a compensator. The features of the exchange interaction and optical absorption spectra are qualitatively analyzed.     

Distribution of the oscillator strengths in the 2<Emphasis Type="Italic">p</Emphasis> absorption spectra of 3<Emphasis Type="Italic">d</Emphasis> transition metal films

The absorption cross-sections in the region of the resonance structure of the 2p ionization threshold of metal films are originally measured for the total series of 3d metals from Sc to Cu. The partial 2p absorption cross-sections are found, and the integral oscillator strengths are determined. The linear dependence of the sum of oscillator strengths in the range from 0 to 80 eV above the L ₃ absorption edge on the number of unfilled 3d states is established. The dependence breaks down for Cr, Fe, and Ni.     

Multiconfiguration Dirac-Fock results for forbidden transitions in the 2<Emphasis Type="Italic">p</Emphasis><Superscript>4</Superscript> configuration

Relativistic configuration interaction calculations with the inclusion of the Breit interaction, quantum electrodynamics and finite nuclear mass corrections have been carried out in the extended optimal level scheme using multiconfiguration Dirac-Fock wavefunctions on the forbidden transition probabilities for the 2p ⁴ ground state configuration of the oxygen isoelectronic sequence for 8 ⩽ Z ⩽ 42. Electric quadrupole and magnetic dipole transition probabilities are reported for transitions between several of these levels. Our results are compared with those from other theories and experiments. Our energy levels are in better agreement with experiment than other theories.     

On the <Emphasis Type="Italic">K</Emphasis><Superscript>+</Superscript><Emphasis Type="Italic">d</Emphasis> interaction at low energies

The Kd reactions are considered in the impulse approximationwithNN final-state interactions (FSI) taken into account. Realistic parameters for the KN phase shifts are used. The “quasi-elastic” energy region, in which the elementary KN interaction is predominantly elastic, is considered. The theoretical predictions are compared with the data on the K ⁺ d → K ⁺ pn, K ⁺ d → K⁰ pp, K ⁺ d → K ⁺ d, and K ⁺ d total cross sections. The NN FSI effect in the reaction K ⁺ d → K ⁺ pn has been found to be large. The predictions for the Kd cross sections are also given for slow kaons, produced from ϕ(1020) decays, as the functions of the isoscalar KN scattering length a ₀. These predictions can be used to extract the value of a ₀ from the data. The text was submitted by the authors in English.     

Exact Results for Topological Strings on Resolved <Emphasis Type="Italic">Y</Emphasis><Superscript><Emphasis Type="Italic"> p</Emphasis>,<Emphasis Type="Italic">q</Emphasis></Superscript> Singularities

We obtain exact results in α′ for open and closed A-model topological string amplitudes on a large class of toric Calabi-Yau threefolds by using their correspondence with five dimensional gauge theories. The toric Calabi-Yaus that we analyze are obtained as minimal resolution of cones over Y ^p,q manifolds and give rise via M-theory compactification to SU(p) gauge theories on . As an application we present a detailed study of the local case and compute open and closed genus zero Gromov-Witten invariants of the orbifold. We also display the modular structure of the topological wave function and give predictions for higher genus amplitudes. The mirror curve in this case is the spectral curve of the relativistic A ₁ Toda chain. Our results also indicate the existence of a wider class of relativistic integrable systems associated to generic Y ^p,q geometries.     

Investigation of <Emphasis Type="Italic">pn</Emphasis> correlations in <Superscript>4</Superscript>He<Emphasis Type="Italic">p</Emphasis> interactions at a momentum of 5 GeV/<Emphasis Type="Italic">c</Emphasis>

Proton-neutron correlations in ⁴Hep interactions are studied in an exclusive experiment by using a 2-m bubble chamber exposed to a 5-GeV/c beam of α particles (the kinetic energy of the protons in the nucleus rest frame is T _p = 620 MeV). Data on the production of pn pairs in 4π geometry for three channels, where it is possible to reconstruct the neutron momentum unambiguously, are used to determine the pn correlation function in ⁴Hep interactions. The experimental results are compared with the predictions of a modified Lednicky-Lyuboshitz model. The value obtained for the root-mean-square radius of the pn-emission region is R _pn = 2.1 ± 0.3 fm. The dependence of the correlation function on the modulus of the total momentum of the emitted nucleon pair and on the direction of the momentum transfer is studied. An indication that the emission of a pn pair proceeds predominantly through the production of a virtual deuteron is obtained.     

Parameterization of the spectra of configurations 3<Emphasis Type="Italic">p</Emphasis>4<Emphasis Type="Italic">f</Emphasis> and 3<Emphasis Type="Italic">p</Emphasis>5<Emphasis Type="Italic">f</Emphasis> of a phosphorus ion P II. Gyromagnetic ratios

In the one-configuration approximation, in the formalism of irreducible tensor operators, and in the intermediate (real) coupling scheme, numerical values of the fine-structure parameters are determined for the 3p4f and 3p5f highly excited configurations of the P II phosphorus ion with the energy-operator matrix in the LK-coupling approximation. With these values of the fine-structure parameters, the energy-operator matrix is numerically diagonalized in the LS-coupling approximation. The gyromagnetic ratios calculated in both basis sets in the absence of a field are compared with one another, as well as with their vector counterparts and the experimental g-factors available for the 3p4f configuration. The experimental and theoretical g-factors calculated with the LS basis set are in good agreement with the sole exception of the ³ F ₂ level. Note that the calculation of g-factors from the Zeeman splitting in the linear region totally confirmed their agreement with the values calculated in the LS basis set (g _LS ) in the absence of a field. The gyromagnetic ratios are the main objectives of this and previous papers, especially for configurations for which experimental data are absent. Apart from the g-factors, the specific features of Zeeman splitting (the crossings and anticrossings of magnetic components) in the 3p5f configurations were determined. These data are to be compared with results of future experiments. Comparison of gyromagnetic ratios calculated in the intermediate coupling scheme with their vector counterparts showed that most levels of the configurations studied are closer than in the LK-coupling scheme.     

Electron impact excitation with the cascade population of the 4<Emphasis Type="Italic">p</Emphasis><Superscript>5</Superscript> 5<Emphasis Type="Italic">s</Emphasis> levels of the krypton atom

Data are presented on the direct and effective, i.e., including the cascade population, electronic excitation cross sections of the 4p ⁵5s levels of the krypton atom from its ground state by the electron impact. The data are made up of the results available in the literature on this process and the results of the measurements performed by the authors.     

Contribution of the <Emphasis Type="Italic">M</Emphasis>1 process to the astrophysical <Emphasis Type="Italic">S</Emphasis>-factor of the <Emphasis Type="Italic">p</Emphasis><Superscript>2</Superscript>H radiative capture

The experimental data on the astrophysical S-factor of the p ²H radiative capture are well described for energies from 1 keV to 10 MeV using the potential cluster model and the Young schemes of orbital cluster state classification with allowance for the E1 and M1 transitions.     

Spectroscopic investigation of thallium 6<Emphasis Type="Italic">s</Emphasis>6<Emphasis Type="Italic">p</Emphasis><Superscript>2</Superscript> configuration at electron-atom collisions: I. Spectra

Thallium emission spectra in the 115–300 nm range excited by electron-atom collisions at electron energies of 12–300 eV are investigated. A number of weak lines that cannot be unidentified using spectroscopic tables are found in the 140–170 nm range. Two of them (144.9 and 148.0 nm) are attributed to the radiative decay of levels that belong to the 6s6p ² configuration and that lie above the ionization potential. A weak emission with an excitation threshold of about 9 eV is revealed in the vicinity of the Tl II resonance line at 132.2 nm. The excitation function of the emission is measured for electron energies below 15.5 eV. It is found that the emission consists of two lines, which also appear due to the excitation of the 6s6p ² configuration and correspond to the radiative decay of levels that are common with the lines at 144.9 and 148.0 nm mentioned above. Their calculated wavelengths are 130.2 and 132.7 nm, respectively.     

VUV 5<Emphasis Type="Italic">d</Emphasis>-4<Emphasis Type="Italic">f</Emphasis> luminescence of Gd<Superscript>3+</Superscript> and Lu<Superscript>3+</Superscript> ions in the CaF<Subscript>2</Subscript> host

The first observation and characterization of Lu³⁺ 4f ¹³5d-4f ¹⁴ luminescence from the CaF₂: Lu³⁺ crystal are reported, and the multisite structure in the spectra of Ce³⁺, Gd³⁺, and Lu³⁺ ions in the CaF₂ host is analyzed with the high-resolution VUV spectroscopy technique using synchrotron radiation. It is shown that vibronic structure in the emission and excitation spectra of interconfigurational transitions in Gd³⁺ and Lu³⁺ ions doped into CaF₂ differs from that observed for Ce³⁺ ions entering mainly at the tetragonal (C _4v ) sites. However, the exact types of sites in which the Gd³⁺ and Lu³⁺ ions reside in a CaF₂ lattice cannot be identified using only the obtained experimental spectroscopid data. The text was submitted by the authors in English.     

A semiempirical calculation of the fine and Zeeman structure of 4<Emphasis Type="Italic">p</Emphasis>4<Emphasis Type="Italic">f</Emphasis> and 4<Emphasis Type="Italic">p</Emphasis>5<Emphasis Type="Italic">f</Emphasis> configurations of Ge I. Gyromagnetic ratios

The gyromagnetic ratios (g-factors) belong to the most important characteristics of atoms. For the 4p4f configuration of a germanium atom experimental values of g-factors are available only for four levels, while similar experimental data on the 4p5f configuration of Ge I are absent. Therefore, a theoretical study of the fine and Zeeman structures is topical for determining the gyromagnetic ratios. All the calculations are performed in the one-configuration approximation with the energy-operator matrix containing a maximum possible number of interactions, including magnetic: spin-orbit (own and other), spin-spin, and also orbitorbit interaction. The fine structure has been examined in three (LS, LK, and jK) approximations in order to establish the nature of coupling in the systems studied and the reliability of g-factors. Apart from the g-factors, in studying the Zeeman splitting, its specific features—the crossing and anticrossing fields of magnetic components— have been determined. A comparative analysis of g-factors was performed that showed that our results are in agreement with the available, albeit few in number, experimental data. At all stages, the corresponding energy-operator matrices were numerically diagonalized, i.e., all the results presented in the paper were obtained in the intermediate coupling scheme.     

Two-proton correlations in <Superscript>4</Superscript>He<Emphasis Type="Italic">p</Emphasis> interactions at a primary momentum of 5 GeV/<Emphasis Type="Italic">c</Emphasis>

Correlations of secondary protons in ⁴Hep interactions are investigated in an exclusive experiment with the aid of a 2-m liquid-hydrogen bubble chamber exposed to an alpha-particle beam of momentum 5 GeV/c the kinetic energy of primary protons in the rest frame of the nucleus is T_p=620 MeV). By using data obtained in 4π geometry for six basic channels of ⁴Hep interaction that lead to the production of two protons, the total correlation function for the pp system is determined, along with two-proton correlation functions for individual channels. Experimental results are compared with the predictions of the modified Lednicky-Lyuboshitz model. The value of R=1.6±0.3 fm is obtained for the root-meansquare spacetime radius of pp emission in ⁴Hep interactions. The dependence of the correlation function on the total momentum of two emitted protons and on the momentum-transfer direction is investigated.     

Measurement of high-<Emphasis Type="Italic">Q</Emphasis><Superscript>2</Superscript> charged current cross sections in <Emphasis Type="Italic">e</Emphasis><Superscript> + </Superscript><Emphasis Type="Italic">p</Emphasis> deep inelastic scattering at HERA

Cross sections for e ⁺ p charged current deep inelastic scattering at a centre-of-mass energy of have been determined with an integrated luminosity of collected with the ZEUS detector at HERA. The differential cross sections , and for are presented. In addition, has been measured in the kinematic range and . The predictions of the Standard Model agree well with the measured cross sections. The mass of the W boson propagator is determined to be from a fit to . The chiral structure of the Standard Model is also investigated in terms of the (1-y)² dependence of the double-differential cross section. The structure-function has been extracted by combining the measurements presented here with previous ZEUS results from e ^- p scattering, extending the measurement obtained in a neutrino-nucleus scattering experiment to a significantly higher Q ² region.Received: 17 July 2003, Published online: 12 November 2003 ^a supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) ^b supported by the German Federal Ministry for Education and Research (BMBF), under contract numbers HZ1GUA 2, HZ1GUB 0, HZ1PDA 5, HZ1VFA 5 ^c supported by the MINERVA Gesellschaft für Forschung GmbH, the Israel Science Foundation, the U.S.-Israel Binational Science Foundation and the Benozyio Center for High Energy Physics ^d supported by the German-Israeli Foundation and the Israel Science Foundation ^e supported by the Italian National Institute for Nuclear Physics (INFN) ^f supported by the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) and its grants for Scientific Research ^g supported by the Korean Ministry of Education and Korea Science and Engineering Foundation ^h supported by the Netherlands Foundation for Research on Matter (FOM) ⁱ supported by the Polish State Committee for Scientific Research, grant no. 620/E-77/SPUB-M/DESY/P-03/DZ 247/2000-2002 ^j partially supported by the German Federal Ministry for Education and Research (BMBF) ^k supported by the Fund for Fundamental Research of Russian Ministry for Science and Education and by the German Federal Ministry for Education and Research (BMBF) ^l supported by the Spanish Ministry of Education and Science through funds provided by CICYT ^m supported by the Particle Physics and Astronomy Research Council, UK ⁿ supported by the US Department of Energy ^o supported by the US National Science Foundation ^p supported by the Polish State Committee for Scientific Research, grant no. 112/E-356/SPUB-M/DESY/P-03/DZ 301/2000-2002, 2 P03B 13922 ^q supported by the Polish State Committee for Scientific Research, grant no. 115/E-343/SPUB-M/DESY/P-03/DZ 121/2001-2002, 2 P03B 07022     

Many-electron character of Rydberg series converging to the ionization thresholds of the 4<Emphasis Type="Italic">p</Emphasis><Superscript>4</Superscript>5<Emphasis Type="Italic">s</Emphasis> states of KrII

The photoionization cross sections of the 4p shell and the 4s main level and 4p ⁴(³ P) 5s ⁴ P _{5/2, 3/2} satellite subvalence levels of KrII have been calculated in the 4s-near-threshold range of excitation energies from 28.48 to 28.70 eV. The calculation takes into account the core relaxation by the methods of the theory of non-orthogonal orbitals, the interaction between resonant states through autoionization channels by solving the complex secular equation, and the interaction between the channels of the continuous spectrum in all orders of the perturbation theory by the K-matrix method. Good quantitative agreement between the energy-integrated theoretical and experimental photoionization cross sections for the satellite levels has been obtained for the first time. It is shown that only simultaneous consideration of the above-mentioned effects leads to such agreement. The resonant structure of the photoionization cross sections in this excitation energy range is related to the autoionization decay of the 4p ⁴5s(⁴ P _1/2)np and 4p ⁴5s(² P _3/2)np Rydberg series. The specificity of this process is that both series manifest themselves not independently but owing to their strong electrostatic interaction with the prominent 4p ⁴(¹ D)5s ² D _5/2 6p _3/2 resonance, which lies in this excitation energy range.     

The excitation cross section of cadmium atoms from metastable 5<Emphasis Type="Italic">s</Emphasis>5<Emphasis Type="Italic">p</Emphasis><Superscript>3</Superscript><Emphasis Type="Italic">P</Emphasis><Subscript>0, 2</Subscript> states by electron impact

By means of the optical method using the technique of crossed electron and atomic beams, we obtained the absolute values of the excitation cross sections of metastable cadmium atoms and their energy dependences. The absolute cross section values reach ∼10⁻¹⁶ cm² (at 30 eV). Sharp resonance-like maxima are observed in the energy dependences of the excitation cross section near the excitation thresholds, which are supposedly related to the formation and decay of negative-ion excited states of.     

Photoluminescence and EPR of porous silicon formed on <Emphasis Type="Italic">n</Emphasis><Superscript>+</Superscript> and <Emphasis Type="Italic">p</Emphasis><Superscript>+</Superscript> single crystals implanted with boron and phosphorus ions

The effect of combined doping by shallow donor and acceptor impurities on boosting the quantum yield of porous-silicon photoluminescence (PL) in the visible and near IR range was studied using phosphorus and boron ion implantation. Nonuniform doping of samples and subsequent oxidizing annealing were performed before and after porous silicon was formed on silicon single crystals strongly doped by arsenic or boron up to ≈10¹⁹ cm^?3. The concentration of known P_b centers of nonradiative recombination was controlled by electron paramagnetic resonance. It is shown that there is an optimal joined content of shallow donors and acceptors that provides a maximum PL intensity in the vicinity of the red part of the visible spectrum. According to estimates, the PL quantum yield in the transitional n ⁺⁺-p ⁺ or p ⁺⁺-n ⁺ layer of porous silicon increases by two orders of magnitude as compared to that in porous silicon formed on silicon not subjected to ion irradiation.     

Jet production in charged current deep inelastic <Emphasis Type="Italic">e</Emphasis><Superscript> + </Superscript><Emphasis Type="Italic">p</Emphasis> scatteringat HERA

The production rates and substructure of jets have been studied in charged current deep inelastic e ⁺ p scattering for Q ² > 200 GeV² with the ZEUS detector at HERA using an integrated luminosity of 110.5 pb^-1. Inclusive jet cross sections are presented for jets with transverse energies GeV and pseudorapidities in the range . Dijet cross sections are presented for events with a jet having GeV and a second jet having GeV. Measurements of the mean subjet multiplicity, , of the inclusive jet sample are presented. Predictions based on parton-shower Monte Carlo models and next-to-leading-order QCD calculations are compared to the measurements. The value of , determined from at for jets with GeV, is . The mean subjet multiplicity as a function of Q ² is found to be consistent with that measured in NC DIS.Received: 5 June 2003, Published online: 10 October 2003