X-ray intensities following the fusions of dμd,dμt and pμd

Muonic X-ray spectra of μ³He and μ⁴He from dμd, pμd, and dμt fusion are analyzed for various target densities. Theoretical values of the intensity ratio μ³He(3→1)/μ³He(2→1) for dμd and pμd fusion at liquid hydrogen density are, respectively, 0.132 and 0.0553. These are in good agreement with the experimental results.     

Contributions of γd → πNN + π0 d channels to the spin asymmetry and the Gerasimov-Drell-Hearn integral for the deuteron

Contributions from the semi-exclusive channels γd → π^± NN + π⁰ d and γd → π⁰ X (X=pn or d) to the deuteron spin asymmetry and the Gerasimov-Drell-Hearn (GDH) integral are explicitly evaluated using an enhanced elementary pion photoproduction operator and a realistic, high-precision potential model for the deuteron wave function. The sensitivity of the results to the elementary pion photoproduction operator is also investigated and considerable dependence is found. Results for the deuteron GDH integral are compared with the measurements from A2 and GDH@MAMI Collaborations.     

Asymptotic Expansions for λ d of the Dimer and Monomer-Dimer Problems

In the past few years we have derived asymptotic expansions for λ _d of the dimer problem and λ _d (p) of the monomer-dimer problem. The many expansions so far computed are collected herein. We shine a light on results in two dimensions inspired by the work of M.E. Fisher. Much of the work reported here was joint with Shmuel Friedland.     

Lax connections and Solutions of the Hybrid Superstring on d ×

In this paper, we show that the Lax connections can yield new classical solutions with a spectral parameter of the hybrid formulism for the Type IIB superstring in an AdS₂ × S² background with Ramond-Ramond flux. This series of classical solutions have the same infinite set of classically conserved charges.     

Microscopic description of the reactions d + d → p + 3H and d + d → n + 3He at low energies

A collective adiabatic approach is used to explore the total and differential cross sections for the reactions d + d → p + ³H and d + d → n + ³He at incident-deuteron energies of up to 6 MeV. All substantially contributing partial waves of order not higher than that of G waves are taken into account. The experimental value of the difference of the cross sections for the above mirror reactions is reproduced theoretically under the assumption that nuclear forces obey the condition of isotopic invariance. The positions and amplitudes of the maxima in the calculated total cross sections virtually coincide with those of the corresponding experimental values. It is shown that, around the maxima of the cross sections under study, dominant contributions to them come from the P wave. The sensitivity of observables to the parameters of nucleon-nucleon interaction is analyzed.     

Relativistic oscillator strengths for the Cs isoelectronic sequence and collapse of ⨍ and d orbitals

Model potential calculations have been performed to investigate the influence of valence-core electron exchange on oscillator strengths in the Cs isoelectronic sequence. It is demonstrated that inclusion of valence-core electron exchange in the model potential calculations of oscillator strengths for transitions involving orbitals which undergo the collapse phenomenon (usually d or f orbitals) is important and may modify the character of the transition (emission or absorption) due to the change in the relative positions of the states involved. In the collapse region, oscillator strengths for these transitions may also depend strongly on the form of the exchange approximation used. The reason for this influence is that valence-core electron exchange greatly facilitates the collapse phenomenon, thus affecting the positions of states and radial transition integrals. For transitions which do not involve orbitals undergoing collapse or occur in members of the isoelectronic sequence distant from the collapse region, the exchange effects, although still important are much weaker and good results may be obtained not only with a model potential employing empirically adjusted exchange but also for a simple, free from adjustable parameters, semiclassical exchange approximation.     

Chiral dynamics and the reactions pp↦dK+ and pp↦dπ+η

We perform a study of the final-state interactions of the K ⁺ and the d systems in the reactions pp↦dK ⁺ and pp↦dπ⁺η. Since the two-meson system couples strongly to the a ₀(980) resonance, these reactions are expected to be an additional source of information about the controversial scalar sector. We also show that these reactions present peculiar features which can shed additional light on the much debated meson-baryon scalar sector with strangeness -1. We deduce the general structure of the amplitudes close to the dK ⁺ threshold, allowing for primary K ⁺ as well as π⁺η production with the two mesons in relative S- or P-wave. The interactions of the mesons are accounted for by using chiral unitary techniques, which generate dynamically the a ₀(980) resonance, and the d interaction is also taken into account. General formulae are derived that allow to incorporate the final-state interactions in these systems for any model of the production mechanism. We illustrate this approach by considering two specific production mechanisms based on three flavor meson-baryon chiral perturbation theory. It is demonstrated that in this scenario the d interactions are very important and can change the cross-section by as much as one order of magnitude. The amount of π⁺ηversus K ⁺ production is shown to depend critically on the primary mixture of the two mechanisms, with large interference effects due to final-state interactions. These effects are also shown to occur in the event distributions of invariant masses which are drastically modified by the final-state interactions of the two-meson or the d system. Received: 28 September 2001 / Accepted: 26 November 2001     

Coupled-Channels Faddeev Equations for the K ??+?d Break-Up Reaction and the Shape of the ��(1405) Resonance

Coupled-channels Faddeev equations are derived for the K ^? + d break-up reaction with inclusion of the isospin breaking effect of the ${\bar{K}^0-K^-}$ mass difference.     

np → ηd near threshold and the s -wave ηN amplitude

We calculate the process np → ηd near threshold using a separable potential model of the coupled ηN - πN - ππN subystems, and a relativistic three-body calculation for the ηd scattering amplitude. The ππN channels are represented by an effective σN channel, and we compare the case where the σ and π masses are related by m _σ = 2m _π and no width is considered, to another where the mass and width of the σ -meson are taken from ππ scattering data. The np → ηd cross-section can be well described up to about 60MeV by models where the real part of the ηN scattering length lies between 0.4≤Re(a _ηN)≤0.6 fm which allows us to determine the s -wave ηN scattering amplitude for -60≤E≤60 MeV.     

Effects of the 3d transition metal doping on the structural,electronic, and magnetic properties of BeO nanotubesEffects of the 3d transition metal doping on the structural,electronic, and magnetic properties of BeO nanotubesEffects of the 3d transition metal doping on the structural,electronic, and magnetic properties of BeO nanotubes

First-principles calculations have been performed on the structural, electronic, and magnetic properties of seven 3d transition-metal （TM） impurities （V, Cr, Mn, Fe, Co, Ni, and Cu） doped armchair （5,5） and zigzag （8,0） beryllium oxide nanotubes （BeONTs）. The results show that there exists a structural distortion around the 3d TM impurities with respect to the pristine BeONTs. The magnetic moment increases for V- and Cr-doped BeONTs and reaches a maximum for Mn-doped BeONT, and then decreases for Fe-, Co-, Ni-, and Cu-doped BeONTs successively, consistent with the predicted trend of Hund＇s rule to maximize the magnetic moments of the doped TM ions. However, the values of the magnetic moments are smaller than the predicted values of Hund＇s rule due to the strong hybridization between the 2p orbitals of the near O and Be ions of BeONTs and the 3d orbitals of the TM ions. Furthermore, the V-, Co-, and Ni-doped （5,5） and （8,0） BeONTs with half-metal ferromagnetism and thus 100% spin polarization character are good candidates for spintronic applications.     

Determination of the reaction-matrix elements of the D(d,n)3He and D(d,p)3H reactions forE d ≤500 keV

All available data of the mirror fusion reactions D(d, n)³He and D(d, p)³H have been subjected to a new analysis in order to extract the matrix elements of all 16 transitions necessary for inclusion of alll2 waves. Their energy dependence was assumed to be governed solely by Coulomb penetrabilities. The Levenberg-Marquardt algorithm was used to fit all experimental data. The experimental data are reproduced satisfactorily. The results compare well with anR-matrix analysis and with refined resonating group calculations. No suppression of quintet entrance-state transitions and therefore no neutron suppression in polarized fusion can be derived from this analysis.This work was funded by the German Federal Ministers for Research and Technology (BMFT) under the contract numbers 06-OK-153 and 06-OK-272     

Assignments of Nonexchangeable Proton Resonances and the Solution Structures of d–TGGGT

In this paper, we report the studies of the solution structures of synthetic pentadeoxyribonucleotide d-TGGGT(NH₄ ⁺ salt) using 2D–NMR. The 1H–NMR experiments with different temperatures and concentrations reveal an equilibrium between single strand and aggregation. In the experimental condition(22°C, 13mmol/ L), the cross peaks in the COSY spectrum are mainly from single strand, and the spin systems of sugar resonances of this component can be assigned. In contrast, the cross peaks in the NOESY spectrum mainly come from aggregation and the sequential assignments of bases, sugar 1′, 2′ and 2″ protons can be carried out. From NOE connectivities, it is obvious that the aggregation adopts a right–handed helix conformation. It is suggested that the aggregation in our experiment corresponds to the tetramolecular complex.     

T → d+n vertex function and its correlation with the triton binding energy and with the doublet nd scattering length

The asymptotic normalization constant C _T ² for the triton is calculated within a two-body model for potentials characterized by a Yukawa-type short-distance behavior and the long-distance asymptotic behavior V(r)→const×r ^?νexp(?μr), where ν=0, 1, 2. It is shown that C _T ² decreases monotonically with increasing ν and that it smoothly decreases with increasing a ₂ κ, where a ₂ is the doublet scattering length and κ is the triton wave number. This behavior is consistent with effective-range theory taking into account the pole of κ cot δ and with the general trend of Faddeev calculations. It is established, however, that some calculations reported previously and performed on the basis of the N/D method yield, on the contrary, a sharp growth of C _T ² . The results of the calculation of the form factor for the T → d+n vertex are compared with the results of the well-known three-body calculation.     

A study of the 29,30Si(α, d)31,32P and the 29,30Si(d, α)27,28 Al reactions

The ${}^{\mathrm{29,30}}\text{Si}\text{(α,}\text{d}\text{)}{}^{\mathrm{31,32}}\text{P}$ reactions have been studied at a beam energy of 25 MeV and the ${}^{\mathrm{29,30}}\text{Si}\text{(}\text{d}\text{, α)}{}^{\mathrm{27,28}}\text{Al}$ reactions have been studied using a 12.3 MeV tensor polarised deuteron beam. The data have been analysed using the microscopic DWBA. Three representations of the nucleon-nucleon interaction have been compared by incorporating the appropriate spectroscopic amplitudes for two nucleon transfer obtained from shell model calculations, in the microscopic form factor.     

Tensor features and dynamical deformation of the 24Mg(2+) nucleus in the reaction 24Mg(d,dγ)24Mg at E d = 15.3 MeV

The results obtained by reconstructing of the experimental angular dependences of polarization tensors, the tensors of orientation of multipole moments, and the dynamical deformation of ²⁴Mg nuclei produced in the 2⁺ state at 1.369 MeV in inelastic deuteron scattering on ²⁴Mg nuclei at E _d = 15.3 MeV for deuteron scattering angles between 25° and 165° in the laboratory frame are presented. The experimental results are compared with the results of calculations based on various versions of the coupled-channel method. The role of spin-orbit and tensor d ²⁴Mg interactions is discussed along with the influence of the reorientation effect. The correlation features of the 2⁺ state of the ²⁴Mg nucleus at 1.369 MeV that were determined in inelastic deuteron and alpha-particle scattering on ²⁴Mg are compared.     

Aeppli and Bott–Chern cohomology for bi-generalized Hermitian manifolds and d′d″-lemma

We define Aeppli and Bott–Chern cohomology for bi-generalized complex manifolds and show that they are finite dimensional for compact bi-generalized Hermitian manifolds. For totally bounded double complexes $(A,d^{\prime }{d}^{″})$, we show that the validity of $d^{\prime }{d}^{″}$-lemma is equivalent to having the same dimension of several cohomology groups. Some calculations of Bott–Chern cohomology groups of some bi-generalized Hermitian manifolds are given.     

Mono and bidimensional1H NMR and inverse detected13C NMR of the duplex d(CA)3·d(TG)3

The unambiguous assignment of the aromatic protons of the duplex d(CA)₃·d(TG)₃ was carried out with the aid of HMQC and HMBC inverse detected¹³C NMR experiments atT=278 K. The NOE connections of these protons with the imino protons of the complementary bases — established by 2D NOESY experiments — indicated that the duplex is characterized by a canonical Watson-Crick basepairing pattern. Monodimensional¹H NMR experiments, also carried out atT=278K, in the presence of varying amounts of NaCl and with water suppression by presaturation and by spin echo techniques, showed that the imino protons of the TA and CG pairs of the duplex exchange with water through a process of local base pair opening and with different exchange rates.